Monday, October 12, 2026

From genetics to lifestyle: understanding the factors that shape breast cancer risk

By HS and SM, intern medical writers

Knowing the risk is the first step towards knowing how and when to screen.

Did you know that breast cancer is the second most commonly diagnosed cancer in the world, next only to lung cancer?

However, in India it is the most commonly diagnosed cancer. According to the Indian Council of Medical Research (ICMR)-National Cancer Registry Programme, the incidence of breast cancer cases in India was projected to reach approximately 2.33 lakhs, in the year 2025.[1,2] Although advances in screening, diagnosis, molecular classification, and treatment have improved outcomes for many patients, breast cancer remains a heterogeneous disease with considerable variation in biological behavior. Nearly 1 out of 28 women is at a risk of developing it during their lifetime.[3] Breast cancer can affect anyone, and it is completely natural to wonder:

Can I actually protect myself from breast cancer?

The honest answer is that there is no magical shield that can guarantee 100% protection. However, risk factors do not presume diagnosis, as many people who develop breast cancer often do not have any risk factors, or people who had risk factors did not actually develop a cancer. Genetic factors only account for 5-10% of the total breast cancer cases.[4]

While the risks are ultimately influenced by a combination of unchangeable factors, including age and genetics, you can actively lower your overall risk through modifiable lifestyle habits such as staying active, maintaining a healthy weight, and limiting alcohol. Most importantly, routine screenings ensure that if breast cancer does occur, early detection may help locate cancers in their localized stage, increasing cancer survival chances up to 99%. Understanding these factors helps you make informed health decisions and discuss appropriate screening and prevention strategies with your doctor.



Risk factors can broadly be divided into two groups.

·       Non-modifiable risk factors:

These are things you cannot change, such as your age, sex, genetics or family history, inherited genetic mutations, previous history of exposure to radiation (particularly at a younger age), dense breast tissue, etc.

·         Modifiable risk factors:

These are the factors which you may be able to influence, such as alcohol intake, physical activity, diet and smoking.

Non-modifiable risk factors:

1.      Age:

The risk for breast cancer increases with age. Most breast cancers are diagnosed after age 50. However, it is important to know that no age is immune to breast cancer. It has been diagnosed in teenagers too, though such cases are extremely rare.

2.      Sex:

If you are a female, then the chances of getting breast cancer is more than that of a male. This is mainly because females are more exposed to hormones such as estrogen and progesterone over their lifetime.

3.      Family history of breast cancer:

Having a family history of breast cancer may increase your risk. The risk may be higher if a first-degree relative, such as a parent, sibling, or child, has had breast cancer, or if several family members on either side of your family had breast cancer.

4.      Previous history of radiation therapy:

Women with previous history of radiation for Hodgkin’s lymphoma before age 30, concomitant chemotherapy with anthracycline has higher chances of getting breast cancer.

5.      Breast density:

Breast density refers to the proportion of fibrous and glandular tissue compared with fatty tissue in the breast. Dense breast is associated with a higher risk of breast cancer as it can create problems for visualizing suspected breast tissue in the mammogram.

6.      Genetic mutations:

About 5% to 10% of breast cancers are hereditary. Women with inherited mutations to certain genes, such as BRCA1 and BRCA2, are at a higher risk of developing breast cancer. These genes are responsible for normal growth of the breast tissues.[5]

7.      Reproductive history:

Both menstrual and reproductive history may increase the risk for breast cancer. Early menstruation (before the age of 12), late pregnancy (after the age of 35), late menopause (after 55 years), or never giving birth may potentially increase the risk for breast cancer.

8.      Reproductive and hormonal factors:

Breast tissue is influenced by hormones, particularly estrogen and progesterone. These are natural female hormones that signal breast cells to grow and divide. The longer your body produces or is exposed to high levels of these hormones over your lifetime, the higher the chances of cell changes.

9.      Exposure to certain drugs:

Drugs such as diethylstilbestrol (DES) were previously used to prevent miscarriage in pregnant women during the 1940s-1970s. Women who took DES have a higher risk of developing breast cancer later in life.

Risk factors you can change:

1.      Not being physically active:

Regular physical activity is an important part of a healthy lifestyle. Women who are physically inactive may have a higher risk of developing breast cancer. Staying active through activities such as walking, cycling, and swimming may reduce overall chances of breast cancer.[6]

2.      Not maintaining a healthy weight after menopause:

Older women who are overweight or obese have a higher risk of getting breast cancer than the ones who are at a healthy weight.

3.      Delaying pregnancy or avoiding breastfeeding:

If you are having your first pregnancy after age 30 without breast feeding, or not having a full-term pregnancy, you may be under an increased risk of breast cancer.

4.      Drinking alcohol:

Alcohol consumption is another factor that may cause breast cancer. Research has found that women who drink alcohol have a higher risk of breast cancer than women who do not drink, and the risk generally increases with the amount of alcohol consumed. This includes different types of alcoholic beverages, such as beer, wine, and spirits. Even small amounts of alcohol may be associated with a slight increase in breast cancer risk.

5.      Taking hormones:

Various hormone replacement therapies and birth control pills available in the market contain both estrogen and progesterone. These introduce external hormones to your system which can raise your risk of breast cancer. You can talk to your doctor about how hormones could affect your risk.

Breast cancer risk is influenced by multiple factors, not just one. Age is one of the strongest risk factors. Reproductive and hormonal factors may also affect risk. If you are concerned with your individual risk, talk to your doctor about healthy lifestyle choices and appropriate screening.

Lifestyle changes may help lower your risk, but it cannot completely prevent breast cancer. Some risk factors, such as age, genetics, and family history, cannot be changed, therefore, regular breast screening and discussing your personal risk with a healthcare professional are important.

Understanding the continuum from genetics to lifestyle is important for developing more individualized approaches to breast cancer prevention and risk assessment. The most important approach is to know about your personal risk, make healthy choices wherever possible, and follow appropriate breast screening recommendations.

References:

1.         Projections Indicate Over 230,000 New Breast Cancer Cases Expected in [Internet]. Breva; 2025 [cited 2026 Oct 12]. Available from: https://breva.in/blogs/breast-cancer/projections-indicate-over-230-000-new-breast-cancer-cases-expected-in-2025-india

2.         Sathishkumar K, Chaturvedi M, Das P, Stephen S, Mathur P. Cancer incidence estimates for 2022 & projection for 2025: Result from National Cancer Registry Programme, India. Indian J Med Res. 2023;156(4–5):598–607. doi:10.4103/ijmr.ijmr_1821_22 PubMed PMID: 36510887; PubMed Central PMCID: PMC10231735.

3.         Dr Mathangi J. Breast Cancer Statistics India 2026. Breast Cancer Statistics India 2026 and Early Detection [Internet]. [cited 2026 Oct 6]. Available from: https://drmathangi.com/breast-cancer-statistics-india-2026/

4.         CDC. Hereditary Breast and Ovarian Cancer [Internet]. CDC; 2024 [cited 2026 Oct 6]. What Causes Hereditary Breast and Ovarian Cancers. Available from: https://www.cdc.gov/breast-ovarian-cancer-hereditary/causes/index.html

5.         DiGrande S. Know the Risk: 5 Breast Cancer Risk Factors | AJMC [Internet]. AJMC; 2018 [cited 2026 Oct 12]. Available from: https://www.ajmc.com/view/know-the-risk-5-breast-cancer-risk-factors

6.         CDC. Breast Cancer [Internet]. CDC; 2026 [cited 2026 Oct 12]. Breast Cancer Risk Factors. Available from: https://www.cdc.gov/breast-cancer/risk-factors/index.html