Breast Feeding - Relationship with Reducing Breast Cancer Dr. Milena Minzberg

The relationship between pregnancy and breast cancer risk is complex and varies significantly based on factors such as age at first birth and number of pregnancies. Women in the UK born after 1960 face a 15% lifetime risk of breast cancer, with postmenopausal women experiencing reduced risk if they have children. Those with one child see a 13% reduction, increasing to 19% and 29% for two and three children respectively. However, the protective effects depend heavily on the age of first pregnancy. Women giving birth before 25 see a 35% reduction in risk, while those over 30 face a 24% increase, a concerning trend as maternal age rises in high-income countries.

Short-term risks after pregnancy include increased breast cancer incidence and aggressiveness, peaking around 5 years post-birth and remaining elevated for up to 20 years. These risks are particularly notable in women without a family history of breast cancer who give birth after 30. Conversely, breastfeeding and early full-term pregnancies have consistently shown protective effects against breast cancer across various populations, suggesting biological mechanisms at play rather than socio-economic factors.

The anatomy of the breast undergoes significant changes throughout a woman's life, influenced by hormonal fluctuations during puberty, pregnancy, and lactation. Breast milk production involves a complex network of lobes, lobules, and alveoli, with hormonal shifts during pregnancy expanding ductal systems and epithelial tissue. While breastfeeding reduces breast cancer risk by influencing hormonal levels and promoting cell differentiation, the exact mechanisms remain an area of ongoing research.

Globally, breast cancer is a major health concern, with incidence rates varying widely between regions due to genetic, lifestyle, and healthcare access factors. Developed countries generally report higher incidence rates but better survival outcomes due to advanced healthcare systems. In contrast, developing nations face higher mortality rates due to late-stage diagnoses and limited access to treatment.

Breastfeeding, recommended globally for its myriad health benefits to infants, also significantly reduces the mother's risk of breast cancer. The longer a woman breastfeeds over her lifetime, the greater the risk reduction due to hormonal changes that suppress cell division in breast tissue, reducing opportunities for genetic mutations that could lead to cancer.

In conclusion, while pregnancy offers some protective benefits against breast cancer in the long term, such as through early full-term pregnancies and breastfeeding, the relationship is nuanced and influenced by multiple factors including age at first birth and family history. Ongoing research continues to explore the biological mechanisms behind these relationships to inform preventive strategies and improve outcomes for women globally.

Stordal B. (2023). Breastfeeding reduces the risk of breast cancer: A call for action in high-income countries with low rates of breastfeeding. Cancer medicine, 12(4), 4616–4625. https://doi.org/10.1002/cam4.5288

Abraham, M., Lak, M. A., Gurz, D., Nolasco, F. O. M., Kondraju, P. K., & Iqbal, J. (2023). A Narrative Review of Breastfeeding and Its Correlation With Breast Cancer: Current Understanding and Outcomes. Cureus, 15(8), e44081. https://doi.org/10.7759/cureus.44081 

Did you know that breastfeeding reduces a mother’s risk of breast cancer and ovarian cancer? While the general public knows the benefits of breastfeeding for infants such as, “fewer episodes of diarrhea, ear infections, and lower respiratory infections, and a lower risk of sudden infant death, diabetes, asthma and childhood obesity,” many do not know the benefits of breastfeeding for the mother (1). Not only does breastfeeding reduces a mother’s risk for some cancers, but also type 2 diabetes and high blood pressure. 

“The American Academy of Pediatrics (AAP) recommends that infants be exclusively breastfed for about the first 6 months of life with continued breastfeeding after the introduction of solid foods for 1 year or longer” (2).  The longer the child is breastfed, there is a greater reduction in risk for both the child and mother. 

Several biological mechanisms have been proposed about the protective effect of breastfeeding on breast cancer risk.  Breastfeeding is linked to hormonal shifts and changes in the molecular histology of the breast, potentially lowering the risk of breast cancer in individuals. Nulliparity, or the absence of childbirth, is a recognized risk factor for luminal-type breast cancer. Both pregnancy and breastfeeding contribute to a reduction in the total number of lifetime menstrual cycles, thereby minimizing exposure to certain hormones linked to an elevated risk of luminal-type breast cancer (1). Research indicates that breastfeeding promotes the differentiation of mammary cells after pregnancy. Differentiated cells are less prone to developing cancerous characteristics. 

While a majority of infants initially receive some breast milk, most do not exclusively breastfeed or sustain breastfeeding for the recommended duration. Only one in four infants remains exclusively breastfed at the age of 6 months, even though four out of five infants start with breastfeeding. Additionally, significant disparities exist among various groups when it comes to breastfeeding practices. These significant disparities are being worked on. 

There are many reasons why women in first world countries stop breastfeeding or choose not to do so. A perceived barrier to breastfeeding is insufficient milk supply. Mothers perceive that their milk supply is insufficient for their infant and not providing enough nutrients. Another barrier is nipple pain and difficulties with latching, which are both discouraging to a trying mother. Another barrier is lack of professional support. First time mothers have little to none breastfeeding exposure and rely on a professional team for proper education on breastfeeding and latching. Many hospitals in the United States are not Baby-Friendly designated. This designation is an initiative made by the WHO/UNICEF as the global standard for hospital care to support breastfeeding, with the Ten Steps to Sucessful breastfeeding at its core (3). 

The CDC states there is a significance in hospital practices that influence the rate of breastfeeding, and how long babies are breastfed.  According to the CDC, “hospitals can Implement the Ten Steps to Successful Breastfeeding and work towards achieving Baby-Friendly designation, use CDC’s Maternity Practices in Infant Nutrition and Care (mPINC) survey customized reports to improve maternity care practices that support breastfeeding, and work with doctors, nurses, lactation care providers, and organizations to create networks that provide clinic-based, at-home, or community breastfeeding support for mothers” (4). In addition mothers and their families can talk to their healthcare providers about breastfeeding plans, and ask about how to get help with breastfeeding (4). 

In conclusion, breastfeeding plays a crucial role in promoting infant health and well-being and contributing to long-term benefits for both mothers and babies.

References:

1. Anstey, E. H., Shoemaker, M. L., Barrera, C. M., O'Neil, M. E., Verma, A. B., & Holman, D. M. (2017). Breastfeeding and Breast Cancer Risk Reduction: Implications for Black Mothers. American journal of preventive medicine, 53(3S1), S40–S46. https://doi.org/10.1016/j.amepre.2017.04.024

2. https://blogs.cdc.gov/cancer/2019/08/01/breastfeeding-for-cancer-prevention/

3. Stordal B. (2023). Breastfeeding reduces the risk of breast cancer: A call for action in high-income countries with low rates of breastfeeding. Cancer medicine, 12(4), 4616–4625. https://doi.org/10.1002/cam4.5288

4. https://www.cdc.gov/vitalsigns/breastfeeding2015/index.html

The main function of the breast is to produce human milk. Estrogen stretches milk ducts and helps them create side branches to carry more milk. Prolactin promotes the production of progesterone and prepares glands for milk production. Progesterone increases the number and size of lobules in preparation for breastfeeding. Breastfeeding has many health benefits for both the mother and baby. Breast milk is essential for proper nutrition for the baby and supports growth and development. Breastfeeding’s significance goes as far as protecting the baby and mom against certain illness and diseases.

Breastfeeding is one of the most effective ways to make sure a child is healthy during the first months of life. According to the World Health Organization fewer than half of infants under 6 months old are exclusively breastfed. Breast milk is considered the ideal food for infants. It is safe, clean and contains antibodies which help protect against many common childhood illnesses. Breastmilk provides the necessary energy and nutrients that are essential for the babies first few months of life and help it develop. Children who are breastfed oppose to children who are not have shown to perform better on intelligence tests, they are less likely to be overweight and less prone to diabetes later in life. The recommendations of breastfeeding include that children initiate breastfeeding withing the first hour of birth and be exclusively breastfed for the first 6 months of life, meaning no other foods or liquids including water. Babies should be breastfed on demand, day, and night, this can be a lot on the mother. Overall, there is only pure benefit to the baby when properly given breastmilk, it is vital for their growth and health. It should not be substituted or taken for granted, other formulas simply do not compare to the benefits of breastmilk.

It is not common information on how beneficial breastfeeding is for a mother. However, the consistent and proper breastfeeding can improve health outcomes for the mother. It is studied that breastfeeding can reduce the mother’s risk of breast and ovarian cancer, type 2 diabetes, and high blood pressure. Positives of initiating breastfeeding that causes short term benefits to the mother include reduction of maternal bleeding after delivery, reduce stress, delay ovulation, and facilitate positive metabolic changes. Reasons that benefit the mother to continue breastfeeding for at least 6 months are, increased postpartum weight loss, prolong lactational amenorrhea, decrease visceral adiposity and reduction of long-term chronic diseases.

When breastfeeding is done as recommended and properly the benefit is immense for both the child and the mother. The child is given antibodies, disease prevention and proper nutrients essential to the health and growth of the child. As for the mother, she can improve her health after pregnancy as it may help her return to “normal” metabolic profile and help her reduction in certain chronic diseases. Breastfeeding is natural and normal, for some reason, the United States has a significantly low number of children being breastfed. Formulations are simply not the same and do not achieve the same benefits as natural breastmilk from a mother.

References:

https://www.cdc.gov/nccdphp/dnpao/features/breastfeeding-benefits/index.html#:~:text=Breastfeeding%20can%20reduce%20the%20mother's,common%20among%20women%20who%20breastfeed.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3508512/

https://www.who.int/health-topics/breastfeeding#tab=tab_3

Natalie Eshaghian & Donna Salib

Breast Feeding

What better way to celebrate Breastfeeding week than to discuss the advantages it offers? The Academy of Pediatrics recommends breastfeeding for at least the first year of life. (1) Breast milk has all of the nutrients that a baby needs in the first six months of life, and is beneficial as it lowers rates of allergies as well as ear and lung infections in the child. According to both the CDC and WHO (2,3), mothers can also benefit from breastfeeding as it decreases the risk of breast, ovarian, and uterine cancer as well as type 2 diabetes and heart disease. Incidence of breast cancer is high with hyperestrogenic conditions, however, when breastfeeding, there is less amount of estrogen in the body. Pregnancy and breastfeeding reduces this hyper estrogenic condition and proliferation of abnormal cells in the breast. For many years, researchers and scientists thought of breast cancer as one disease, but we now know there are many different types.

Breast cancers are classified by many types, but it is not well understood how different factors such as family health history, diet, exercise, and having children affect each type of breast cancer. Researchers have determined that having children seems to increase the risk of developing estrogen receptor negative cancer, but that breastfeeding greatly reduces this risk. Essentially, women do not need to stop giving birth due to the fact that pregnancy and childbirth could increase a woman's chances of developing breast cancer, instead the women can simply modify their lifestyle to breastfeed to prevent the disease. Although research states that having children can increase the risk of a certain type of breast cancer, the number of child births still remains at about 3 million each year, but it is important to understand how a woman can decrease their risk of developing the cancer by simply giving their child their proper nutrients naturally through breast feeding.

Breastfeeding can reduce the rate of triple negative breast cancer, an aggressive and deadly form of the disease, by up to 60%. Estrogen receptor negative tumors are not as easily treated, and sometimes progress more quickly and are more common in younger women as well as African American women. The CDC looked at women across the U.S from 2011-2015 and found that out of 885 African American women in South Carolina, only 10% (about 85 women) breastfed for 6 months, and only 70 women nursed for an entire year (4). This is important for African American women who are less likely to breastfeed, but more likely to carry a gene mutation that predisposes them to triple negative breast cancer. (5) Health officials can warn these specific groups, such as African American women, in different ways to lower their risk. Although breastfeeding is the method of choice clinically to allow your child to receive the proper nutrients naturally, many women switch to different methods to save them time and effort during their pregnancy/post childbirth. Formulas have been rising in popularity, and this can indirectly increase a woman’s chances of breast cancer since they are not breastfeeding.

A meta-analysis in 2015 (6) evaluated if breastfeeding is as strong of a protective factor for all breast cancer subtypes, and it concluded that it protects most strongly for hormone receptor negative cancers. These subtypes are mostly prevalent in younger women and explains why breastfeeding is a stronger protective factor when women breastfeed when they are younger. Again, this is another group of individuals that health officials can warn to protect themselves from certain breast cancers.

The same way many people have risk factors for certain disease states, and will modify their lifestyles to lower their risk of those diseases, so to with breast cancer and breast feeding. Although breast feeding does not ensure that you will not get breast cancer, it also does not mean if you don’t breastfeed you will get breast cancer. Breast-feeding simply decreases the chances and risk of developing breast cancer. It is simply a way of modifying your lifestyle to try to prevent developing cancers. Overall, breastfeeding has many benefits to both the child and the mother, so it is important to look into the benefits and consider switching to breastfeeding over other methods.

References:

1. ​​Section on Breastfeeding. Breastfeeding and the use of human milk. Pediatrics. 2012;129(3):e827-e841. doi:10.1542/peds.2011-3552

1. Why it matters. Centers for Disease Control and Prevention. https://www.cdc.gov/breastfeeding/about-breastfeeding/why-it-matters.html. Published February 22, 2021.

1. Breastfeeding. World Health Organization. Available at: https://www.who.int/health-topics/breastfeeding#:~:text=Women%20who%20breastfeed%20also%20have,breastfeeding%20rates%20and%20duration%20worldwide Date Accessed: August 9, 2021.

1. Anstey EH, Chen J, Elam-Evans LD, et al. . Racial and Geographic Differences in Breastfeeding - United States, 2011-2015 [published correction appears in MMWR Morb Mortal Wkly Rep. 2017 Aug 04;66(27):815]. MMWR Morb Mortal Wkly Rep. 2017;66(27):723-727. Published 2017 Jul 14. doi:10.15585/mmwr.mm6627a3

1. Anstey EH, Shoemaker ML, Barrera CM, O'Neil ME, Verma AB, Holman DM. Breastfeeding and Breast Cancer Risk Reduction: Implications for Black Mothers. Am J Prev Med. 2017;53(3S1):S40-S46. doi:10.1016/j.amepre.2017.04.024 https://www-ncbi-nlm-nih-gov.jerome.stjohns.edu/pmc/articles/PMC6069526/

1. Islami F, Liu Y, Jemal A, et al. Breastfeeding and breast cancer risk by receptor status--a systematic review and meta-analysis. Ann Oncol. 2015;26(12):2398-2407. doi:10.1093/annonc/mdv379 https://www-ncbi-nlm-nih-gov.jerome.stjohns.edu/pmc/articles/PMC4855244/

257,300. 257,300 represents the number of cases of breast cancer diagnosed in men and women in the United States each year. Cancer is a disease in which cells in the body grow out of control and cause harm to the body. Breast Cancer is when specifically, breast cells grow out of control. It can spread through blood vessels to other parts of the body. There are different kinds of breast cancer. The two most common kinds are invasive ductal carcinoma and invasive lobular carcinoma. Invasive ductal carcinoma is when the cancer cells grow outside the ducts into other parts of the breast tissue and it can also spread to other parts of the body. Invasive lobular carcinoma is when cancer cells spread from the lobules to other parts of the breast tissue and it can also spread to other parts of the body.

What are some warning signs of breast cancer? When you go to a regular doctor’s check-up, they routinely screen for breast cancer by checking for a lump in the breast or underarm. They also ask if you have noticed any swelling of the breast, irritation, change in size or the shape of the breast as well as any pain area. Other symptoms include nipple discharge including blood as well as pain in the nipple area.

How can I lower my risk of getting breast cancer? Living a healthy lifestyle with exercise regularly is a great way to help lower the risk. For women, breastfeeding children if possible has shown to have a correlation to lowering the risk of developing breast cancer. Breastfeeding can lower the risk of breast cancer if women have been breastfeeding for longer than 1 year. It does so because it helps lower estrogen levels which therefore lowers the body’s chances of having cells that are mutated. This is considered a hormonal change which plays a role in delaying the menstrual period. Hormones such as estrogen can promote breast cancer cell growth therefore when these hormones are limited due to breastfeeding then the chance for being diagnosed with breast cancer can be lowered.

There are some cases in which women are pregnant and may have already had breast cancer treatment or are currently pregnant as well as having breast cancer. Women are able to breastfeed a baby after having breast surgery but they are unable to breastfeed while having chemotherapy, radiotherapy, hormone or targeted therapy. If a woman has a mastectomy surgery in which she removes one of the breast tissues, then breastfeeding is possible from the breast that did not have a surgery performed on it but if both breast tissues were removed then breastfeeding is not possible. During chemotherapy treatment, chemotherapy drugs have a possibility of passing to the baby through the breast milk therefore it is advised to not breastfeed during chemotherapy treatment. Radiotherapy treatment, which is used to kill cancer cells using x-ray beams, will have an effect on women breastfeeding because it may cause a mastitis or an infection in the breast which can be difficult to treat. Targeted therapy and hormone therapy will also have an affect on women who breastfeed. These drugs will pass through the breast milk and have an effect on the baby. Medications such as Herceptin and Tamoxifen are great for the treatment of breast cancer but can have detrimental effects on the baby’s health because it can affect the normal division of cells in the body of an infant. Alternative options include breastfeeding an infant through donated breast milk as well as using formula milk. There are other options that will provide the child with benefits needed in order to grow healthy.

“Breastfeeding and Breast Cancer Treatment.” Breast Cancer Now, 9 Nov. 2020, breastcancernow.org/information-support/facing-breast-cancer/breast-cancer-in-younger-women/breastfeeding-breast-cancer-treatment.

“Breastfeeding for Cancer Prevention.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, blogs.cdc.gov/cancer/2019/08/01/breastfeeding-for-cancer-prevention/.

“How Is Breast Cancer Diagnosed?” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, 14 Sept. 2020, www.cdc.gov/cancer/breast/basic_info/diagnosis.htm.

MD Anderson Cancer Center, and Brittany Cordeiro. “Breastfeeding Lowers Your Breast Cancer Risk.” MD Anderson Cancer Center, MD Anderson Cancer Center, 9 Oct. 2014, www.mdanderson.org/publications/focused-on-health/breastfeeding-breast-cancer-prevention.h19-1589046.html.

In the US breast cancer is the leading cause of death from cancer in women, as well as the most common cancer affecting women worldwide. Breast cancer risk increases after menopause and it is a heterogeneous disease with multiple tumor subtypes that may be hormone-related. Those diagnosed with breast cancer before or after menopause will experience different effects of hormones.

Breast cancer is commonly classified by hormone receptor type, tumors that express either estrogen receptors (ER) as ER+ or progesterone receptors (PR) as PR+ are either Luminal-A or Luminal-B types. But breast cancer tumors that express human epidermal growth factor receptor2 (HER2) and basal-like tumors are hormone receptor negative. Hormone receptor positive cancers specifically Luminal A cancers are most common and have a better prognosis than hormone negative cancers which can prove difficult to treat.

Breast tissue normally contains fat, glandular tissue (lobes), ducts and connective tissue. Hormones (estrogen and progesterone), insulin, and growth factors will signal breast tissue to grow especially during periods of puberty, pregnancy and lactation (breast feeding). According to the American Institute for Cancer Research, breast feeding decreases the risk of premenopausal and postmenopausal breast cancer in the mother. Breastfeeding will also reduce risk of endometrial and ovarian cancers, hypertension, and diabetes. While the infant will experience less prevalence of childhood obesity, asthma and lower risk of infections among other benefits.

Increased levels of sex steroids may increase the chance of developing postmenopausal breast cancer, specifically elevated circulating levels of estrogens and testosterone. Although not completely clear, breastfeeding is linked to hormonal changes and changes in molecular histology in the breast leading to reduced breast cancer risk. During pregnancy, blood levels of estrogen and progesterone reach an all time peak and after delivery those levels fall dramatically. During the lactation period, postpartum mothers may experience amenorrhea or infertility which may influence androgen levels which may impact the risk of carcinogenesis.

Nulliparity is when a woman has never given birth while parity is a woman who has given birth. Nulliparity is a risk factor for luminal breast cancer, but pregnancy (parity) & breastfeeding will decrease menstrual cycles therefore decreasing hormonal exposure that cause luminal breast cancers. Breastfeeding and cessation of breastfeeding will reduce breast cancer risk due to the removal of cells with DNA damage from breast tissue. The pregnancy-lactation cycle (PLC) is a process where the breast evolves into a milk-producing gland to meet the immune-protective, developmental and nutritional needs of the newborn. During lactation cessation the breast reverts to a resting state. Changes during this period will permanently alter the morphology and molecular characteristics of the breast tissue which may reduce breast cancer risk. Breast milk contains mature epithelial cells, leukocytes, and stem-like progenitor cells. Breast milk might serve as a bio-specimen to understand the mechanisms involved in the pregnancy-lactation cycle; as well as identifying other biomarkers that can potentially serve as risk assessment and even early breast cancer detection.

According to the American Academy of Pediatrics, the recommended period of breastfeeding is the first 6 months of the infant’s life with additional introduction of appropriate foods and should last a year. Breastfeeding coalitions and cancer prevention coalitions play an important role in state-level public health and can promote breastfeeding to reduce risk of breast cancer.

1. Anstey EH, Shoemaker ML, Barrera CM, O'Neil ME, Verma AB, Holman DM. Breastfeeding and Breast Cancer Risk Reduction: Implications for Black Mothers. Am J Prev Med. 2017;53(3S1):S40-S46. doi:10.1016/j.amepre.2017.04.024

2. Faupel-Badger JM, Arcaro KF, Balkam JJ, et al. Postpartum remodeling, lactation, and breast cancer risk: summary of a National Cancer Institute-sponsored workshop. J Natl Cancer Inst. 2013;105(3):166-174. doi:10.1093/jnci/djs505

3. World Cancer Research Fund/American Institute for Cancer Research. Continuous Update Project Expert Report 2018. Diet, Nutrition, Physical Activity and breast cancer. Available at dietandcancerreport.org

Breast cancer is the most common type of cancer across the entire world. Just like most cancers, early detection of cancer increases the patient to be cured of the disease. Across the world, every 3 minutes, a woman gets diagnosed with breast cancer. When combined, that is about 1 million cases annually.

Breast cancer is sort of an umbrella term in that aspect that there are many different types of breast cancers. Ductal cancers are the most common type of breast cancer. The cell malignancies develop in the ducts that carry milk to the nipple in breastfeeding mothers. Lobular breast cancers are when are cancer starts in the glands that make the milk in breastfeeding mothers. In different stages of breast cancer, the cancer cells can metastasize into the blood or lymph system. While there are multiple risk factors for breast cancer in women, the most influential is a woman’s age and a woman’s family history. Women between the ages of 40 and 69 years old are at the highest risk of developing breast cancer. Other risk factors include reproductive health of women, when her first pregnancy was, oral contraceptive use, late menopause, and use of hormone replacement therapies.

Research has shown, breastfeeding can decrease a woman’s risk of developing breast cancer. Lactation suppresses ovulation in a woman, and the production of breast milk changes the construction of the breast tissue which can potentially reduce the risk of malignancy developing in that area.

There is a vast number of benefits of feeding a child breast milk. There are also components of breast milk that could contribute to its anti-cancer effects. Breast milk contains alpha-lactalbumin. Tumor and bacterial cell death have been shown to be induced by a human milk complex of alpha-lactalbumin and oleic acid (HAMLET). HAMLET induces apoptosis in tumor cells, especially to malignancy cells while leaving normal cells unharmed. HAMLET is transferred from the breastmilk to a child’s stomach where it can kill viruses or premalignant cells in the GI tract of breastfed babies.

It has been proven in studies that breastfeeding mothers have a decreased risk of hormonal associated cancers, including breast cancer, ovarian cancers, and uterine cancers. While the mechanism as to why this has not been proven, it is thought to be reduced by 2 mechanisms- the differentiation of breast tissue and the decrease of lifetime ovulations.

A meta-analysis was done with 27 studies to look at the relationship between breast cancer and breastfeeding. Data showed that breastfeeding decreased the risk of hormone receptor-negative breast cancers. These breast cancers are more common in younger women and generally have a poorer prognosis. After looking at the studies, the relationship between breastfeeding a receptor-positive breast cancer needs to be investigated with more studies.

References:

Islami F, Liu Y, Jemal A, et al. Breastfeeding and breast cancer risk by receptor status--a systematic review and meta-analysis. Ann Oncol. 2015;26(12):2398-2407. doi:10.1093/annonc/mdv379

MD Anderson Cancer Center, Cordeiro B. Breastfeeding lowers your breast cancer risk. MD Anderson Cancer Center. https://www.mdanderson.org/publications/focused-on-health/breastfeeding-breast-cancer-prevention.h19-1589046.html. Published October 9, 2014. Accessed January 30, 2021.

Protective factors for breast cancer | Breast Cancer | Cancer Research UK. https://www.cancerresearchuk.org/about-cancer/breast-cancer/risks-causes/protective-factors. Published January 24, 2020. Accessed January 30, 2021.

Breast cancer is the most prevalent form of cancer in women in the United States. Early detection is key for these types of cancers as it can be cured when it is in its premature stages. Risk increases with aging between ages 40-69 years old and first degree relative family history of breast cancer. Risk also increases if a woman has not had a child before the age of 30 years old. Breast feeding is thought to reduce the risk of breast cancer. But how is this possible? The theory is that lactation stops ovulation and leads to the encouragement of differentiation within breast tissue that prevents malignancies from occurring. Human milk also has many components of immune response that has the ability to fight pathogens and limits inflammation damage on tissue set forth by the body’s other immunomodulators. In addition to preventing cancer, it is theorized that production of breast milk and breastfeeding has been linked to the reduction of autoimmune disease like rheumatoid arthritis where the body is attacking itself as an immune response. Breast milk also has antimicrobial effects through enzymes that stop the growth of certain bacteria. These enzymes include lysozyme and lactoferrin. Breast milk also contains cytokines that are also involved in the body’s immune response. Alpha lactalbumin plays a large role in inducing apoptosis in cells that may grow in a tumor like manner through uncontrolled and unregulated growth. This preventative complex is called HAMLET (human milk complex of alpha lactalbumin and oleic acid). The unique property of this is that the cells that grow normally through differentiation do not undergo apoptosis and are resistant to the HAMLET; the complex only kills premalignant cells. HAMLET also kills virus transformed or premalignant cells in the gastrointestinal tract of breastfed children, reaffirming the theory that use of breast milk plays a role in immunological response of the body. Clinical studies have sought out the risks involved in developing certain cancers and it was noted that in several cancers including breast, ovarian and uterine cancers that they were more prevalent in women that had never breastfed before. In addition to the immune benefits for the mother, breastfeeding also exudes benefits on building the child’s immune system. By stopping ovulation, less estrogen is released in the women’s body therefore lessening the likeliness of developing cancerous growth in cells. Exposure to estrogen is linked to development of cancer. Therefore, it is theorized that the reduction in the lifetime number of ovulatory cycles is a risk reducing factor in breast cancer. Breast tissue is also shed during breastfeeding that can help remove potentially damaging cells that can become cancerous, also reducing the risk of breast cancer. Breastfeeding mothers are also more likely to be mindful of the food they are ingesting and opt for healthier dietary options. A healthy lifestyle is always a benefit in reducing cancer risk and promoting longevity for the body. Furthermore, mothers are more likely to abstain from cigarette or tobacco smoking and alcohol when breastfeeding. Coupled with the preventative effects of breast feeding on breast cancer, promotion of a healthier lifestyle may in turn reduce overall risk of a female actually getting breast cancer if she currently is or has breastfed in the past.

Reference:

Romieu II, Amadou A, Chajes V. The Role of Diet, Physical Activity, Body Fatness, and Breastfeeding in Breast Cancer in Young Women: Epidemiological Evidence. Rev Invest Clin. 2017 Jul-Aug;69(4):193-203. doi: 10.24875/ric.17002263. PMID: 28776604.

Breast cancer is the most common cancer among women, and is slowly becoming the number one killer in females. Studies have shown that breastfeeding reduces the risk of developing breast cancer. The first study we will look at takes place in India. In India, there are 100,000 new cases annually and breast cancer is second only to cervical cancer. The study was set in the tertiary care institute of Haryana which is situated in Northern India. All patients that took part in this study were confirmed to be new female breast cancer patients. The present study supports the fact that breastfeeding has a statistically significant role in the reduction of developing breast carcinoma risk. After adjustment for parity, age, and other risk factors, increasing the cumulative duration of lactation, was associated with the decreased risk of breast cancer among premenopausal women (P = < 0.001) but not among postmenopausal women (P = 0.51). A younger age at first lactation was significantly associated with a reduction in the risk of premenopausal breast cancer (P = 0.003). In addition, it also found that breast cancer risk decreased by 7% for every 12 months of breastfeeding. Many other studies also reported that as the duration of breastfeeding increases, the risk of breast carcinoma decreased.

The next study we are going to analyze decided to put their focus on African-American females. Black women in the U.S. have lower rates of breastfeeding and nearly twice the rates of aggressive subtype breast cancers compared to white women. In addition to individual challenges to breastfeeding, black women may also encounter contextual barriers such as a lack of acceptance, inadequate support, and unsupportive work environments. This study showed that in a pooled analysis of three of the four studies, among black women with children, breastfeeding was associated with a reduced risk of ER− breast cancer (OR=0.81, 95% CI=0.69, 0.95) but not ER+ breast cancer. Therefore we can assume that breastfeeding may only help with ER− breast cancer subtype.

References

Babita, Kumar N, Singh M, Malik JS, Kalhan M. Breastfeeding reduces breast cancer risk: a case-control study in north India. Int J Prev Med. 2014;5(6):791-5.

Anstey EH, Shoemaker ML, Barrera CM, O'neil ME, Verma AB, Holman DM. Breastfeeding and Breast Cancer Risk Reduction: Implications for Black Mothers. Am J Prev Med. 2017;53(3S1):S40-S46.

The most common cancer is breast cancer and it is one of the leading causes of death in women. The American Academy of Pediatrics recommends that infants should be exclusively breastfed for the first 6 months, followed by continuation of breastfeeding with introduction of solid food until the infant is 1 year, and then breastfeeding can be continued if mutually desired by the mother and infant. Breastfeeding has been shown to reduce breast, endometrial, and ovarian cancer risk. Studies found that there is a 4.3% lower risk of breast cancer for every 12 months a woman breastfeed. The mechanism is not well known but some theories include hormonal changes and breastfeeding can help differentiation of cells after a pregnancy. It also provides numerous benefits to the infant by strengthening their immune system so they have fewer occurrences of diarrhea, ear infections and lower respiratory infections. 

In the US, the overall number of cases of breast cancer is similar between white and black women in the US but in 2013, black women had a higher mortality rate of 28.2 per 100,000 black women. According to the article, black women had a decreased rate of breastfeeding in the US as well as twice the incidence of triple-negative breast cancer when compared to white women. Breastfeeding is a modifiable risk so it is important to address disparities and barriers in order to potentially reduce breast cancer risks. Some barriers black mothers have stated that they faced includes receiving inadequate information about breastfeeding from providers, lack of breastfeeding acceptance in their community, lack of support at work, etc. It is extremely significant to intervene and provide adequate support such as providing information about breastfeeding in prenatal care, peer counseling and enhanced breastfeeding programs for mothers.  

References

Anstey EH, Shoemaker ML, Barrera CM, O'Neil ME, Verma AB, Holman DM. Breastfeeding and Breast Cancer Risk Reduction: Implications for Black Mothers. Am J Prev Med. 2017;53(3S1):S40-S46. doi:10.1016/j.amepre.2017.04.024

MD Anderson Cancer Center, and Brittany Cordeiro. “Breastfeeding Lowers Your Breast Cancer Risk.” MD Anderson Cancer Center, MD Anderson Cancer Center, 9 Oct. 2014, www.mdanderson.org/publications/focused-on-health/breastfeeding-breast-cancer-prevention.h19-1589046.html.

Thank you for your contribution Ed, very and interesting information about HAMLET Pharma. Also, great references. See you worked at finding many good sources.

There is growing interest in modifiable risk factors for breast cancer as research continues to be conducted into the pathophysiological and epidemiology of breast cancer. Among these risk factors, breastfeeding carries a special interest because its long-term benefits and harm are still being studied.

The World Cancer Research Fund (WCRF) found that breastfeeding actually decreases the risk of breast cancer in the mother. Lactational amenorrhea, as a byproduct of breastfeeding, can reduce the total sex hormonal exposure that typically occurs during menstrual cycles, which in turn, impacts cancer risk. Production of Human Alpha-lactalbumin Made Lethal to tumor cells (HAMLET) in breastfeeding mothers is also thought to play a role. HAMLET is found in higher concentrations in breastfeeding mothers and incites programmed cell death solely in cancerous cells while leaving normally functioning cells alone. Pharmaceutical companies, namely HAMLET Pharma, are taking advantage of this mechanism by researching its viability in other forms of cancer. It has recently announced successful Phase 1 and 2 trials in demonstrating HAMLET safety and efficacy in patients with bladder cancer. The WCRF also postulates that exfoliation of breast tissue during lactation may help eliminate cells with DNA damage and mutations.

The results from a massive 2002 study that compiled and analyzed data coming from 47 different studies among 30 countries found that relative risk of breast cancer decreased by 4.3% for every 12 months of breastfeeding and decreased by 7.0% for each birth. There was no significant difference in developed or developing countries, age, menopausal status, ethnicity, the number of births, and age during first pregnancy. When considering its colossal sample size (n=147,275), while factoring the aforementioned variables, breastfeeding’s protective benefits had huge implications in clinical practice. Currently, both the American Institute for Cancer Research and the World Health Organization now recommend mothers to breastfeed exclusively for at least six months for these protective benefits. At which point, the child should be continued to be breastfed along with other appropriate nutrients. There is less information on the potential benefits of breastfeeding in reducing ovarian cancer risk but is still an avenue worth exploring.

Lactation is linked to benefits in not only mothers but also children. It is generally accepted that breastfeeding protects against infections and diseases common during infancy, like bacteremia, respiratory tract infections, otitis media, diabetes mellitus, and childhood obesity. The transference of the mother’s immunological components like, immunoglobulin (Ig) A antibodies, leukocytes, and lysosomes, through lactation serves to boost the child’s immune system while it is still developing.

There have been concerns over the incidence of allergic and autoimmune diseases in breastfeeding children, which are largely unsubstantiated. In fact, most studies corroborate that breastfeeding serves to protect against the risk of allergic and autoimmune diseases like allergic rhinitis, atopic dermatitis, inflammatory bowel diseases, and type-1 diabetes mellitus in later life.

References

1. Benefits of Breastfeeding. AAP.org. https://www.aap.org/en-us/advocacy-and-policy/aap-health-initiatives/Breastfeeding/Pages/Benefits-of-Breastfeeding.aspx. Accessed July 5, 2020.

2. Lactation (breastfeeding). World Cancer Research Fund. https://www.wcrf.org/dietandcancer/exposures/lactation-breastfeeding. Published March 10, 2020. Accessed July 5, 2020.

3. Franca-Botelho ADC, Ferreira MC, Franca JL, Franca EL, Honorio-Franca AC. Breastfeeding and its Relationship with Reduction of Breast Cancer: A Review. Asian Pacific Journal of Cancer Prevention. 2012;13(11):5327-5332. doi:10.7314/apjcp.2012.13.11.5327

4. Anstey EH, Shoemaker ML, Barrera CM, O’Neil ME, Verma AB, Holman DM. Breastfeeding and Breast Cancer Risk Reduction: Implications for Black Mothers. American Journal of Preventive Medicine. 2017;53(3). doi:10.1016/j.amepre.2017.04.024

5. Jackson KM, Nazar AM. Breastfeeding, the Immune Response, and Long-term Health. J Am Osteopath Assoc 2006;106(4):203–207.