Menopausal Hormone Therapy (MHT) is widely prescribed for postmenopausal women to ease symptoms of menopause such as hot flashes, vaginal dryness, and sleep disturbances.
There are two types of Hormone Replacement Therapy (HRT):
According to recent research, it has been found that Combination Menopausal Hormone Replacement Therapy increases the risk of breast cancer by 75%, even when administered for a very short time. In contrast, estrogen-only hormone therapy increases the risk of breast cancer only when used for longer than 10 years.
Some genes promote higher growth of estrogen receptors during menopausal hormone therapy. This increases the risk of ER-positive breast cancer.
The CYP19A1 gene contains instructions for the production of a protein involved in estrogen biosynthesis.
Certain changes in this gene are associated with poor treatment outcomes of hormone therapy in women in the early stages of ER-positive breast cancer.
The POMP gene contains instructions for the production of proteasome maturation protein. A study revealed two regions in the POMP gene showing interaction with hormone therapy that increased the risk of breast cancer.
Obesity: According to a study published in Cancer Epidemiology Biomarkers in 2008, both types of hormone therapy are associated with breast cancer risk. The risk is further influenced by the body mass of the individual and the clinical characteristics of the tumors.
In women with BMI <25 kg/m2, estrogen therapy was associated with a 60% increase in breast cancer risk after 10 years of the therapy. The risk increased with combined therapy. Combined therapy with estrogen and progesterone was also strongly associated with ER-positive tumors.
Alcohol consumption: Drinking alcohol while taking postmenopausal hormone replacement therapy can increase the risk of developing breast cancer. This is because drinking alcohol increases estrogen levels, and when combined with the estrogen in hormone therapy, it significantly increases estrogen in a woman’s body.
A study was conducted to analyze drinking habits and hormone therapy use in over 5,000 Danish women for over 20 years. The researchers found that postmenopausal women who took Hormone Replacement Therapy (HRT) and drank 1 or 2 alcoholic drinks per day had three times higher risk of breast cancer than women who did not drink and were not taking HRT. Also, postmenopausal women taking HRT who drank more than 2 alcoholic drinks per day had a five times higher risk of breast cancer than women who did not drink and were not taking HRT.
Smoking: Smoking has been associated with an increased risk of breast cancer in women. This risk is much higher for women who smoke while taking postmenopausal hormone therapy.
The year 2020 saw around 2.3 million women being diagnosed with breast cancer. As per the latest report from GLOBOCAN published in February 2021, breast cancer has surpassed lung cancer in being the most prevalent cancer type in the world.
Compared to the high risk of breast cancer in women, the risk of breast cancer in men is a minuscule 0.5-1%. A significant reason for the high risk and prevalence of breast cancer in women is attributed to the reproductive hormone, i.e., estrogen and progesterone fluctuations.
To understand the relationship between the menstrual cycle and breast cancer risk, we must know that the most common breast cancers are hormone receptor-positive breast cancers - the cancer cells have estrogen or progesterone or both types of receptors.
These breast cancer cells grow and multiply when exposed to estrogen and progesterone. However, a few types of breast cancer are hormone-receptor negative, which means that these breast cancer cells have no hormone receptor cells and are often more challenging to treat.
Every girl who begins her menstrual cycle has a 5% risk of developing breast cancer in her lifetime. This is because the mammary glands begin forming and remain under the influence of different reproductive hormones as soon as a girl hits puberty, during pregnancy, and even during lactation.
The constant fluctuations in estrogen and progesterone levels during a woman’s reproductive life affect the mammary gland function, cell growth, turnover, and immune cells like the regulatory T cells and the macrophages.
Together, these effects cause increased instability of the individual’s genome, increase their susceptibility to genetic mutations, reduce their immunity, and trigger breast cancer development.
Menopause does not cause breast cancer, but the risk of developing breast cancer increases as the woman ages. According to statistics, a woman who attains menopause after 55 years of age has an increased risk of breast, ovarian, and uterine cancers.
This risk is also greater if a woman starts menstruating before the age of 12 years. Therefore, the longer a woman’s reproductive life, the longer her breast tissue is exposed to hormonal fluctuations, increasing her risk for breast cancer.
It has been observed that postmenopausal women have a lower risk of breast cancer compared to premenopausal women of the same age and with the same childbearing pattern. Also, the risk of breast cancer increases by 3% for each year that menopause gets delayed.
So, women who attained menopause later than 55 years of age had a 30% increased risk of breast cancer than women who reached menopause at 45 years of age.
Postmenopausal breast cancer is known to be less aggressive than breast cancer that occurs in younger women. However, obesity or increased weight is an independent risk factor for breast cancer in menopausal women. This is because serum estradiol (a form of the female hormones estrogen) is increased in obese patients, triggering breast cancer development.
Another study re-iterated the findings mentioned above, stating that lower age of menopause had a protective effect and reduced breast cancer risk compared to the higher age of the woman. This protective effect may be more substantial in leaner women.
Many women take combined hormone therapy to relieve menopausal symptoms like hot flashes and osteoporosis. This treatment is also called Hormone Replacement Therapy (HRT).
In this therapy, estrogen and progesterone are combined and administered to postmenopausal women to help manage their symptoms.
However, HRT increases a woman’s risk of developing breast cancer, stroke, heart attack, and blood clots.
Genetics plays a significant role in the development of breast cancers. Around 5% to 10% of breast cancers occur when an abnormal gene is passed from the parent to the child.
The most commonly inherited genes that lead to breast cancer are the BRCA1 and BRCA2 genes. However, genes that influence the risk of breast cancer in postmenopausal women include- ESR1, PGR, XRCC1, VDR, CAT, CYP2C19, and XRCC3, among others.
ESR1 or the Estrogen Receptor 1 gene provides instructions for the production of estrogen receptor production and ligand-activated transcription factor. These estrogen receptors play a role in growth, development, sexual development, and reproductive functions. Unfortunately, they also play a vital role in breast cancer development, endometrial cancer, and osteoporosis.
rs9340799 is a Single Nucleotide Polymorphism (SNP) in the ESR1 gene and located on chromosome 6. A study on Mexican women showed that women carrying the XbaI (WT/G or G/G) ESR1 genotype have a 12.26 times greater risk of developing postmenopausal breast cancer than those carrying the WT/WT genotype.
However, women with t or the wild type of XbaI had no association with breast cancer. Also, postmenopausal women who were both heterozygous and homozygous for XbaI had a strong association with breast cancer.
PGR or Progesterone Receptor gene mediates the physiological effects of the hormone progesterone, which plays a vital role in the reproductive cycle in women.
rs10895068 is an SNP in the PGR gene, which is located on chromosome 11. Having two AA alleles or at least one A allele increases the risk of breast cancer in postmenopausal women by 2.5 times compared to those with the GG genotype.
Lifestyle changes can help reduce the risk of breast cancer in postmenopausal women.
Gaining weight after menopause can increase a woman’s risk for breast cancer. One must maintain a healthy weight throughout their life to reduce the risk of cancer (According to The American Cancer Society)
Though the direct link between alcohol consumption and increased risk for breast cancer has not been established yet, consuming even lower amounts of alcohol can increase your risk for breast cancer.
Studies have shown that the longer a woman breastfeeds, the lower her risk for breast cancer. For example, researchers have found that for every 12 months that a woman breastfeeds, her risk for breast cancer decreased by 4.3%
Women who opt for hormonal therapy after menopause must speak with their doctor as these therapies increase the risk for breast cancer. Ask for non-hormonal alternatives or short-term hormone therapy options to manage menopausal symptoms.
Following a healthy diet low on red meat, processed foods, sugary foods, and fat can reduce your risk for breast cancer. However, the association between diet and breast cancer is still under research.
Smoking increases the risk for all types of cancer, including breast cancer. Therefore, women who are smokers must quit the habit to lower their risk of developing breast cancer post-menopause.
It is recommended that women with a familial history of breast cancer undergo genetic counseling. This can help determine the course of action to reduce their risk and chances of developing breast cancer.
Routine doctor visits and breast exams are recommended for all women above the age of 35 years. Regular monitoring reduces the chances of late detection and improves prognosis.
Smoking is an ancient cooking technique that exposes meat to smoke and slow-cooks it for long hours. The smoke adds a flavor of its own to the meat and gives the cooked meat a unique taste that people love.
This cooking technique dates back to the paleolithic era (old stone age). There are two reasons why meat is smoked.
One of the chemicals produced due to burning wood while smoking food is Polycyclic Aromatic Hydrocarbon (PAH). PAHs are carcinogenic (cancer-causing) agents. There are two ways PAH damages the DNA.
While people can be exposed to PAHs by inhaling cigarette smoke, staying in places with high air pollution, and through occupation exposure, consuming smoked meat is a direct form of dietary PAH exposure.
When you cook fat-rich meat on an open fire, the fats and juices from meat splash on the fire and lead to smoke and flames. The PAH-rich smoke sticks to the meat, making the food carcinogenic.
A study analyzed the PAH content in different smoked foods. It was reported that meat smoked with natural wood had higher levels of carcinogenic PAHs than meat smoked using liquid smoke flavorings (artificial flavoring that can be used as a substitute for natural wood smoke).
According to the study, smoked salmon had a range of PAH/kg of 86.6mg, and cooked ham had 29.8mg/kg of PAH. On the other hand, smoked shrimp had a low PAH/kg value of 9.3.
Excess consumption of smoked meat can increase the risk of developing different kinds of cancer, including breast cancer. Smoked meat consumption is also associated with an increased mortality rate in breast cancer survivors.
A long-term study identified 1508 women with invasive breast cancer in 1996 and 1997. These women were monitored for approximately 17.6 years. Among these women, 237 died because of breast cancer. Researchers analyzed the average smoked meat intake in these women.
Women who consumed an excess of smoked meat in this group had a 31% higher mortality risk.
According to the American Cancer Society, there are more than 3.8 million breast cancer survivors in the country, including those still in treatment and those who have completed treatment. These women can increase their survival rate by limiting the consumption of smoked meat.
Changes in certain genes can increase or decrease a person’s risk for developing breast cancer on the consumption of smoked meat.
The CYP1A1 gene (cytochrome P450 family 1 subfamily A member 1 gene) helps produce the CYP1A1 enzyme, part of the cytochrome P450 family of enzymes (CYP 450). This enzyme helps eliminate a variety of drugs and chemicals from the body. It also plays a role in the bioactivation of PAHs, converting them into a more toxic intermediary that can cause cancer.
rs1048943 is a single nucleotide polymorphism or SNP in the CYP1A1 gene. It is associated with breast cancer risk. The A allele of this SNP is associated with excess consumption of smoked meat and an increased risk of breast cancer.
| Allele | Implications |
| A | Higher risk of breast cancer with higher lifetime intake of smoked meat |
| G | Regular risk of breast cancer with higher lifetime intake of smoked meat |
The CYP1B1 gene (cytochrome P450 family 1 subfamily B member 1 gene) helps produce the CYP1B1 enzyme. This enzyme also plays a role in eliminating various endogenous (internally produced) and exogenous (externally produced) hormones, lipids, chemicals, and drugs.
rs 10175338 is an SNP in the CYP1B1 gene. It is associated with breast cancer risk. The T allele of this SNP is associated with excess consumption of smoked meat and an increased risk of breast cancer.
| Allele | Implications |
| T | Higher risk of breast cancer with higher lifetime intake of smoked meat |
| G | Regular risk of breast cancer with higher lifetime intake of smoked meat |
The SULT1A1 gene (Sulfotransferase 1A1 gene) helps produce the SULT1A1 enzyme. This enzyme plays a role in the sulfation of many drugs and chemicals, including PAHs.
People with the SULT1A1 His/His genotype of the SNP rs1042028 of this gene had an increased risk of breast cancer from consuming excess smoked meat than those with the SULT1A1 Arg/Arg genotype.
Grilling, barbecuing, and smoking are just a few of the different ways of cooking meat. There are other alternate healthier cooking methods:
Choose lean-cut meat over fat-rich meat when you want to smoke, grill, or barbecue it. This way, excess fat will not drip over the fire and trigger smoke and flames. If you get a fat-rich portion of meat, you can trim the fat edges before cooking.
Some people also pre-cook meat before smoking it. This way, the excess fat is pre-cooked and does not drip down much.
Do not consume parts of the meat that are charred because of smoking. These contain the most amounts of PAH. You can trim the charred parts before you serve the meat on the table.
Overcooking is one reason why meat gets charred or overburnt while smoking or grilling it. Use a thermometer to immediately remove the meat from heat after it is cooked to avoid charring.
Fresh fruits and vegetables have antioxidants that can prevent DNA damage and protect against cancers.
A 2019 study analyzed the relationship between fruit and vegetable consumption and the risk of breast cancer in 182,145 women aged between 27 and 59. The study proves that women who consumed more cruciferous and yellow/orange vegetables and fruits had a lower risk of breast cancer.
When you are occasionally eating smoked meat, include a large portion of fresh salad with the meal. The salad can make you partially full, prevent excessive meat consumption, and protect the body against cancers.
Chemotherapy is one of the many options available to treat cancer. Chemotherapy involves using drugs to stop cancer cells in the body from growing, multiplying, dividing, and spreading. Chemotherapeutic drugs are of different types, and not all of them work in the same way.
While chemotherapy affects the cancer cells, the drugs used in the treatment cannot differentiate between normal and cancerous cells, which results in some damage to healthy cells and tissues.
The most common example of this is the loss of hair in people undergoing chemotherapy treatment.
Though chemotherapy is one of the primary treatment options for cancer, other newer treatments may be preferred for certain types of cancer.
Chemotherapy is used as one of the main treatments for breast cancer cases, during which drugs are used to target and destroy breast cancer cells.
The drugs may be administered orally (by mouth) or intravenously (injected directly into the veins).
In most breast cancer cases, chemotherapy is used alongside surgery, radiation, and hormone therapy.
Chemotherapy improves breast cancer treatment outcomes and allows the individual to live longer and enjoy a better quality of life.
However, chemotherapy administered for breast cancer can have side effects, which may be mild and temporary.
In breast cancer cases, chemotherapy may be given in the following scenarios:
Chemotherapy may be given before breast cancer surgery to reduce the tumor’s size and make it easy to remove with a less extensive surgical procedure. This procedure is called neoadjuvant therapy and is used to remove large breast tumors.
In some cases, chemotherapy is given after a surgical procedure has been done to remove the tumor. This is called adjuvant chemotherapy, and it is shown to reduce any remaining cancer cells that may have been left behind after the surgery. Chemotherapy given after a breast cancer removal surgery reduces the chances of recurrence.
Chemotherapy is the primary treatment of choice in advanced breast cancer cases where cancer has spread outside the breast to the underarm area.
Common Drugs Used in Adjuvant and Neoadjuvant Therapies include:
Chemotherapy drugs used in the treatment of advanced breast cancer include:
Early breast cancer cases are usually treated with a combination of chemotherapeutic drugs, but advanced cases of the disease are mostly treated with single drugs.
If breast cancer has been diagnosed as HER-positive (Hormone Receptor-Positive), chemotherapy drugs may be supplemented with one or more drugs targeting the HER-2 receptors.
Chemotherapy for any type of cancer, including breast cancer, can have side effects. Some common side-effects of chemotherapy include:
Hair loss, also called alopecia, is very common during breast cancer chemotherapy. This happens because the chemotherapy drugs target rapidly dividing cells– both healthy and cancerous cells.
Hair follicles are one of the many rapidly dividing cells in the body found in the skin. When chemotherapy drugs are looking to destroy any rapidly dividing cells, they also destroy hair follicles. This results in hair thinning and loss after a few days of chemotherapy. Hair loss usually happens very quickly following just a few chemotherapy sessions.
Analyzing genetic risk factors can help develop an effective way to reduce chemotherapy-induced alopecia in breast cancer patients.
ATP-binding Cassette Subfamily B Member 1 is a part of the ATP-Binding Cassette family of genes. These genes make proteins (called ABC proteins) that help transport various molecules across cell membranes in multiple tissues.
These ABC proteins also help decrease the accumulation of xenobiotic compounds (compounds not produced by the body and are found in the body) like drugs in the case of multidrug-resistant.
rs1202179 is a Single Nucleotide Polymorphism, or SNP found in the ABCB1 gene located on chromosome 7.
The C allele of this SNP has been linked to a decrease in the expression of the ABCB1 and subsequent increased risk of chemotherapy-induced alopecia (pCIA) in women being treated for breast cancer.
This effect is due to the accumulation of transporting drugs like docetaxel, resulting from P-glycoprotein deficiency. P-glycoprotein is a protein produced by the ABCB1 gene to eliminate the drug.
Deficient P-glycoprotein causes an increased exposure of hair follicles to docetaxel damage, resulting in hair fall.
Protocadherin-related 15 or PCDH15 is a gene that gives instructions for the production of membrane proteins.
These membrane proteins are responsible for retinal and cochlear functions and maintaining calcium-dependent adhesion between cells in the body.
The presence of the G allele in SNP rs7919725 in the PCDH15 gene increases the risk for drug-induced grade 2 alopecia.
Transmembrane Protein 132C or TMEM132 C is located on chromosome 12. It plays a role in cell adhesion, i.e., how cells attach to their neighboring cells.
rs11059635 is an SNP in the TMEM132C gene. The G allele of this SNP plays a role in chemotherapy-induced alopecia due to its response to Paclitaxel.
Calcium voltage-gated channel auxiliary subunit beta 4 or CACNB4 is a gene that provides instructions for making calcium channels.
Calcium channels are essential for transporting calcium ions inside the cells. They enable cells to generate and transmit electrical impulses for muscle contractions, cell-to-cell communication, and regulate genes.
Therefore, any abnormal changes in the CACNB4 gene can cause neurological and muscular conditions.
rs3820706 is an SNP in the CACNB4 gene and is located on chromosome 2.
The G allele of SNP rs3820706 plays a role in chemotherapy-induced alopecia.
Non-genetic factors that influence hair loss during breast cancer chemotherapy include:
Hair loss during chemotherapy is dreaded by many women undergoing treatment for breast cancer. Many methods have been studied that can prevent hair loss due to breast cancer chemotherapy. These include:
In this method, ice packs or an ice cap are placed on the scalp during a chemotherapy session. These help contract the blood vessels in your scalp to prevent the chemotherapy drugs from reaching your hair follicles.
Some studies have shown that this prevention method is applicable only with certain chemotherapeutic drugs like taxanes. A study published in 2017 in the Journal of the American Medical Association stated that using scalp cooling in women with stage I and II breast cancer resulted in less than 50% hair loss after the fourth chemotherapy session.
Scalp cooling or using ice caps has its side effects, such as discomfort or headaches due to the cold.
Another method to prevent hair loss during breast cancer chemotherapy is scalp compression. This method may be used with or without scalp cooling. Clinical trials are still underway to determine the effectiveness of scalp compression on hair loss prevention but what is known so far is that this method is less effective than scalp cooling.
Medications are often recommended to manage hair loss caused due to breast cancer chemotherapy. These medications do not prevent hair loss but help in faster regrowth. Common medications that help hair regrowth include topical application of 2% Rogaine (minoxidil) and Panicum miliaceum.
Bevacizumab is a medication used in the treatment of certain types of cancers. It is sold under the brand name Avastin. This medication is often used along with chemotherapy to prevent further growth of the tumor cells.
Bevacizumab is known as an anti-vascular endothelial growth factor monoclonal antibody. Vascular Endothelial Growth Factor (VEGF) is a signaling protein that helps form blood vessels in the body. Blood supply is essential for cells to grow and multiply as it provides oxygen and nutrients. By acting as an anti-VEGF antibody, the medication starves the cancer cells and prevents their growth.
This is a biological medication (made from living organisms) approved by the US FDA (Food and Drug Administration). It is currently used as a first and second-line treatment option for colorectal cancers and as a first-line treatment option for non-small cell lung cancer.
Bevacizumab is also used to treat renal cell carcinoma, ovarian cancer, severe glioblastoma (tumor affecting the spine and brain), and advanced cervical cancer.
In 2008, the US FDA approved bevacizumab to treat metastatic (cancer that spreads from the primary location to other organs) HER2-negative breast cancer. In 2011 though, the FDA removed the medicine from the list of approved drugs for treating breast cancer.
According to the FDA, the potential side-effects and risks of this medication were much higher than its effect on breast cancer. They argued that bevacizumab only slightly increased the cancer-free period and did not increase the overall survival rate.
Though the medication has been removed from the approved drug list, doctors can still use it for breast cancer treatment with the patient’s approval.
There are many side effects of using Bevacizumab, and one such significant risk is bevacizumab-induced hypertension. Hypertension is consistently high blood pressure over 140/90.
Three theories explain how bevacizumab usage can cause hypertension.
NO is a molecule that is produced by almost all types of cells in the human body. NO helps the blood vessels relax and prevents high blood pressure. Studies show that reduced VEGF activity because of bevacizumab causes a decrease in the production of NO. Low NO levels lead to an increase in blood pressure.
Many experts support this theory because, in most patients, the blood pressure normalizes once they stop receiving Bevacizumab.
VEGF proteins are essential for the growth and maturation of the glomerular network in the kidneys. These are groups of small blood vessels located at the beginning of all the nephrons of the kidneys. The glomerular network filters the blood before it reaches the nephrons.
VEGF inhibition leads to abnormalities in the growth and maturation of the glomerular structure. This can lead to a condition called proteinuria. Proteinuria is the presence of excess proteins in urine.
Certain studies report that people with proteinuria have a higher risk of developing hypertension.
Pre-eclampsia is a pregnancy complication that leads to high blood pressure. In pregnant women with pre-eclampsia, low VEGF levels are noted. As a result, this theory states that VEGF inhibition may be one reason for pre-eclampsia and, therefore, hypertension.
A 2010 meta-analysis published in the American Journal of Hypertension analyzed the relationship between bevacizumab therapy and hypertension. The analysis looked at 20 studies and a total of 12,656 cancer patients. According to the study, people treated with bevacizumab had a higher risk of developing high blood pressure.
Another meta-analysis studied the relationship between bevacizumab and hypertension in 72 clinical trials involving 21,900 patients. According to the study, 25.3% of these patients developed hypertension, and 8.2% had grade 3 and grade 4 hypertension.
A different meta-analysis analyzed the prevalence of hypertension in 3155 non-small cell lung cancer patients. The study reported that 19.55% of people developed hypertension after being treated with bevacizumab, and 6.95% developed high-grade hypertension.
The SV2C gene (Synaptic Vesicle Glycoprotein 2C gene) produces the SV2C protein. It plays a role in the normal functioning of the neural and endocrine cells and helps in low-frequency neurotransmission.
rs2059157 is a Single Nucleotide Polymorphism or SNP in the SV2C gene. The T allele of this SNP has been associated with an increased risk of bevacizumab-induced hypertension.
| Allele | Implications |
| T | Increased risk of bevacizumab-induced hypertension |
| C | Normal risk of bevacizumab-induced hypertension |
rs10051982 is an SNP in the SV2C gene. The A allele of this SNP has been associated with an increased risk of bevacizumab-induced hypertension.
| Allele | Implications |
| A | Increased risk of bevacizumab-induced hypertension |
| G | Normal risk of bevacizumab-induced hypertension |
The effect of bevacizumab is dose-dependent. People who were treated with a higher dose of the medication (>10 mg/kg) had a 7.5-times higher risk for developing hypertension.
People aged 60 and above have a higher risk of developing bevacizumab-induced hypertension when treated for cancer.
People with BMI levels of 25 and above have a higher risk of developing bevacizumab-induced hypertension.
Those who have had high blood pressure before bevacizumab treatment are at a higher risk for developing high-grade bevacizumab-induced hypertension.
Among cancer patients who receive Bevacizumab, the risk of developing hypertension depends on the type of cancer. People with breast cancer or renal cell carcinoma show the highest risks for bevacizumab-induced hypertension.
People with below pre-existing health conditions before bevacizumab treatment are at higher risk of developing hypertension during the treatment.
If your doctor suggests bevacizumab medication along with chemotherapy, then talk to your doctor to understand the risks associated with the drug. Understand how effective it could be to treat your breast cancer and if the benefits outweigh the risks.
The blood pressure starts rising from the first cycle of bevacizumab treatment. Make sure you closely monitor your levels at home and in a professional setup regularly. Talk to your doctor and opt for hypertension medications to prevent making the condition worse.
If you are already diagnosed with hypertension, make sure to stabilize your blood pressure levels before starting cancer therapy.
Antihypertensive drugs help bring down blood pressure levels. It is recommended that you start on these along with your cancer treatment to prevent the risk of bevacizumab-induced hypertension. Make sure to consult a medical practitioner before getting started on any antihypertensives.
Some lifestyle changes can also help manage the condition.
Genetic testing before opting for bevacizumab will tell you how risky you are for developing hypertension during cancer treatment. If you are a high-risk patient, mention this to your doctor so they can monitor your blood pressure levels more frequently.
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The breast size of a woman keeps changing as she ages. At puberty, growth hormones and estrogen together cause breast development in girls. Breast size increases during pregnancy and breastfeeding. There is also a subtle increase in breast size during every menstrual cycle.
After menopause, the breasts go through atrophy. The term muscle atrophy refers to the loss of muscle tissue. Atrophy causes a reduction in breast size.
Here are a few ways how breast size could contribute to breast cancer risk:
Bigger breasts make it difficult to identify lumps. Most women meet with a doctor when they self-examine the breasts and find a possible lump. Women who have larger breasts may not be able to identify the tumor before it gets big enough to push through the fat layers.
Hence there can be a delay in diagnosis and treatment, increasing the risk of complications.
Bigger breasts are commonly noticed in obese and overweight women. Obesity is a very significant non-genetic factor that increases breast cancer risk.
A study published in the International Journal of Cancer studied the relationship between breast size in premenopausal women and cancer risk.
The study assessed 89,268 premenopausal women in the age range of 29-47. They were followed up after 8 years. Out of these women, 803 had been diagnosed with breast cancer. The study recorded that women with BMI levels less than 25 and a bra cup size of more than D had a higher risk of developing breast cancer.
The ZNF703 gene contains instructions for the production of Zinc Finger Protein 703. This gene has been associated with the development of breast cancer.
It behaves as a “classical oncogene” that regulates the growth and development of cells in breast cancer cell lines.
Oncogene is a mutated gene or gene containing errors that contribute to the development of cancer.
rs7816345
rs7816345 is a single nucleotide polymorphism or SNP in the ZNF703 gene. This SNP influences breast size and breast cancer risk.
The C allele of this SNP has been associated with bigger breast size and an increased risk for breast cancer.
According to some studies, breast cancer in women is less common in Asia than in Western countries. These studies report that this could be because the average breast size in Asian women is lesser than in Western countries, which brings down the risk.
Larger breasts have more adipose tissue. With more adipose tissue, the local estrogen levels increase. These local estrogen levels act as a slow-releasing source of carcinogens (cancer-causing agents). This increases the risk of developing breast cancer.
The breast parenchymal pattern is the proportion of glandular tissues to fatty tissues in the breasts. Glandular tissues in the breasts help make milk and include the lobes and ducts. A dense breast parenchyma pattern makes it difficult to identify tumors and hence causes diagnostic delays and complicates the cancer condition.
HRT is used in treating the symptoms of menopause. HRT helps in balancing the levels of estrogen and progesterone in the body.
According to a 2001 study, women who used HRT had increased breast density and hence had an increased risk of late diagnosis of breast cancer. Women who continued HRT for an extended period had consistently high breast densities throughout their life.
Genetic testing of BRCA genes can help you understand your risk for breast cancer. People with a family history of breast cancer or other risk factors should especially consider it.
Obesity increases adipose tissues in the body, including in the breasts. This increases one’s risk of developing all kinds of cancer, including breast cancer. Losing weight can help bring down the risk considerably. Obese women with breast cancer have worse disease progression and lower overall survival rates.
Breast augmentation surgery is a process of changing the shape, size, and look of breasts. Some women use silicone implants to improve the look of breasts. In the United States, 2 million women have opted for implants in the past.
A study analyzed the impact of breast implants in 11,676 women between the years 1973 and 1986. Out of these, only 41 patients ended up with breast cancer. The expected number in the usual population was around 86. This study hence reports that breast augmentation surgery brings down the risk of breast cancer.
This surgery is done to reduce the size of breasts. Here, breast tissues and excess skin from around the breasts are removed. Studies prove the number of breast cancer cases after surgical reduction mammoplasty was lesser than the expected numbers.
