Risk Factors for Breast Cancer

Would a change of lifestyle help?

What are my chances of
developing breast cancer?

In a general population, most women will have 'some' chances of developing breast cancer (even if they have the healthiest of the lifestyles), while some women will have an 'higher' chance of developing breast cancer. There is nothing line 'zero' chance or 'no' chance of developing breast cancer. All of us are at some risk, while some have a higher risk. So let us discuss these 'risk factors' which determine the chances of developing breast cancer. Before that, please understand one point - a breast cancer - or for that matter, any cancer in the body - happens because the 'genes' which control the cell multiplication and other factors in the cells of the breast, have become 'faulty' and allow the cells to multiply like crazy, forming tumours and more tumours. Depending on how the gene becomes faulty, we can divide breast cancer into two types:

Hereditary or Familial Breast Cancer: Here, the faulty gene is 'passed' from parents to children and so on. Having received a 'faulty gene' highly increases the chances of developing breast cancer. Such Familial Breast Cancers account for 6% to 8% of all breast cancers.
Non Familial Breast Cancer: The person here is normal, and there are no 'faulty genes' received from parents. But combination of certain factors (lifestyle, health, environmental etc.) can cause a 'normal' gene to suddenly become 'faulty' which then cause a cancer in the breast. 92% of all breast cancers are non familial.

I will write on Familial Breast Cancer, sometime in the future. The discussion on the page is about the 'Non Familial' Risk Factors - in simple words - 'General Risk Factors' for Breast Cancer which are common for each and every one of us.

General Risk Factors for Breast Cancer

Like an exam answer, this can be enumerated as follows:

  • Gender: Breast cancer is much the more commoner in females. Out of every 100 cases of breast cancer, only 1 may be in a male.

  • Age: As the age increases, the chances of developing breast cancer increases. The usually has a peak, and keeps on changing over decades. presently it is seen that the peak is at around 40 to 60 years, and then decreases after 60 years of age.

  • Stress: Stress is a general risk factor that increases chances of developing any cancer. Even when a cancerous cell is formed, it may still be destroyed by normal body mechanisms. Stress has been known to depress immunity and stressful life will definitely add to the risk of developing a cancer, though slightly.

  • Hormone Replacement Therapy (HRT): This has been realized as an important risk factor. Hormone replacement therapy consists of giving a combination of estrogen and progesterone to relieve menopausal symptoms like hot flashes, loss of sexual desire, etc. In June 2002, a large trial of estrogen and progesterone in healthy postmenopausal women, by the WHI (Women's Health Initiative) was stopped early when researchers found that women who took the hormones had an increased risk of developing breast cancer and heart disease. So if at all HRT is indicated, it must be taken with a clear idea of risk of breast cancer and awareness about screening.

  • Oral Contraceptives: There is a slightly higher risk of developing breast cancer in ladies taking oral contraceptives. Again, the play of hormones is thought to be responsible.

  • Breast Density: A high breast density on a mammogram is considered as one of the strongest risk factors for developing breast cancer. This breast density can be on a mammogram by calculating the amount of radiodense areas which represent the breast tissue.

  • Obesity: Obese individuals have a higher incidence of developing breast cancer. This effect may be related to the production of estrogen by the fat cells. Obesity can be calculated by the BMI (Body mass Index). Increasing BMI is associated with an increasing risk of breast cancer.

  • Diet: A healthy balanced low fat high vegetable diet, and regular fruit intake will decrease chances of developing breast cancer. Vitamin D is also thought to have a protective effect, trials are going on regarding the same.

  • Radiation Exposure: An exposure to radiation in the second or third decades of life will increase the chances of developing breast cancer in the future. This would include patients of Hodgkin's disease, intra thoracic tumours etc, for which radiation has been given.

  • Lack of Exercise: Regular exercise and brisk walking helps to tone the body, burn the unnecessary fat and create a general feeling of well being. A regular exercise will be helpful to curb the risk of cancer.

  • Alcohol intake: Regular daily intake of alcohol may increase the risk of developing breast cancer.

There are many more factors. The ones mentioned above are the commoner ones. Understanding risk factors for cancer helps, since some of them are modifiable, for example, lack of exercise. One can definitely make a habit of daily brisk walking or some form of exercise to stay fit and healthy and reduce the risk of all cancers. Similarly, another risk factor - stress. Stress is universal, I have it, you have it, all have it. It's not possible to avoid stress. If it has to come, it will come. We are individuals with emotion, after all. But one can definitely beat stress - music, meditation, reading etc. We can calm our mind by Yoga and meditation techniques.

The Role of Estrogen

Estrogen is a 'hormone'. It is present in all of us. Males have it in much lesser amounts, females have it much more. Estrogen is a very 'good' hormone and has a 'protective' effect on the heart, bones and other systems - in fact, it is one of the reasons why females have lesser heart issues and other problems than males.
Estrogen has a 'stimulatory' effect on breast cells - it 'pushes' them to multiply. That's fine. usually, it's not a problem. But 'continuous' pushing to multiply and multiply, in the presence of other risk factors, can sometimes convert a normal breast cell into a naughty 'cancerous' cell, which then goes on multiplying and forming 'lumps' or 'tumours'.

So keeping in mind, this role of estrogen, let us understand how estrogen rises and falls during a normal mentstrual cycle.

A 'normal' menstrual cycle lasts around 28 days (plus or minus a few days).

In the first 14 days of the cycle, Estrogen levels rise and reaches a peak around the 14th day when 'ovulation' happens.

After ovulation (around 14th day), estrogen decreases drastically, and another hormone called 'Progesterone' takes over, for the next 14 days. Menstruation happens after that. With start of menses, the Progesterone decreases and Estrogen again starts rising.

This cycle keeps on repeating, every single menstrual cycle, right from the age at which menstruation begins (around 10 to 15 years of age) till menopause (around 45 to 55 years of age). The only time this cycle breaks and Estrogen levels are very low, is during pregnancy, when Progesterone hormone is there throughout. Otherwise, Estrogen always keeps coming in the first half of cycle. And every single time Estrogen levels rise, it keeps 'pushing' the breast cells to multiply.

Majority of gynecological disorders and diseases affect only the first half of the menstrual cycle and the second half usually remains unchanged. So if a lady has a prolonged periods for whatever reason, it is always the first half which is prolonged and the second half stays remarkably constant (14 days). So, for example, if a lady's menstrual cycle is of, say 40 days, then the last 14 days are of Progesterone, whereas first 26 days is due to Estrogen. Few long cycles like this do not make a difference, but long standing disorders do. Repeated 20 to 25 days of estrogen action over a long time, could possibly push one cell of the breast to become 'cancerous'. Now, I wish to add here, this is just one theory. If your cycles are long, don't panic at all. All women with long cycles are not going to get cancer. Very very very few may do. And besides, this is only 'one' of the factors, there are other risk factors which need to be present, to result in that 'push'.

Core Biopsy Needle for Breast tumour

Now let's study this image. The horizontal line on the image is the age of the woman in years. The begining of menstrual cycle (called as 'menarche') is marked, and the age at first pregnancy is marked. Remember, during pregnancy, levels of Estrogen drop drastically, and all the 'pushing' effect on the breast cells slowly reverses.

The upper graph tells about the situation few decades back. Normal age of menarche was around 14 to 16 years, and first pregnancy around 24 to 25 years. So there was 'non stop' Estrogen effect on the breast cells for around 8 to 9 years (25 - 16 = 9), till pregnancy happened, and all its effects on the breast cells reveresed.
The lower graph tells about the situation presently. Normal age of menarche is around 10 to 12 years, and first pregnancy around 28 to 30 years. So there is 'non stop' Estrogen effect on the breast cells for around 18 to 20 years (30 - 12 = 18), till pregnancy happens, and all its effects on the breast cells start reversing.

The above is just a rouhg example, for your understanding. But you see, there is a definite increase in 'unopposed' and 'non stop' stimulation of breast cells by Estrogen in the present day life style. This is one of the factors resulting in increased incidence of breast cancer in younger women today.

Prolonged Estrogen Effect

Keeping in mind, the role of Estrogen, the factors which allow prolonged and unopposed Estrogen effect, on the breast, are as follows:

  • Menstrual History: Early menarche (the age when the first menstrual cycle started), and late menopause (the last menstrual cycle) are both responsible for an increased risk of developing breast cancer, the principle being the same, estrogen having more time to act on the breast. Over decades, the average age of menarche is shifting to early due to a variety of causes.

  • Reproductive History: A lady who has the first child after 30 years of age has an increased risk of developing breast cancer. And so is the risk for a lady who has never borne a child. Pregnancy halts the action of estrogen; progesterone is the main hormone of pregnancy. Pregnancy has a protective effect against breast cancer. However, in a very small section of ladies, who are seen to develop breast cancer within a few years of delivery, it has been postulated that the surge (spurt) of estrogen that occurs in very early pregnancy, may actually be responsible, and then the pregnancy has no protective effect here. Hence we do see a few cases of breast cancer during pregnancy or within a few years of delivery. These tend to be very aggressive cancers

  • Disorders affecting menstrual cycles: It has been postulated that disorders which prolong the menstrual cycles may cause an increased risk of developing breast cancer. There are no studies, which have proven this.

What do we learn?

Some risk factors are modifiable - stress, exercise, diet, healthy sleeping habits, etc. We can definitely try to adapt a healthy lifestyle. This will surely decrease to some extent, our chances of developing breast cancer. However, even if we adapt the best of lifestyles, we should not let our guards down. If a cancer has to happen, it will happen. We can't change that. But we can definitely detect it on time, which can result in a cure. Being alert, being aware, is what matters. It's the line between life and death; between health and suffering.
If you have read this page, then I would insist, that you must read the sections on 'Symptoms of Breast Cancer' and 'Early Detection of Breast Cancer', you will find the links in the menu below.


All the links are in blue colour. You can click the links to go to that page. The page you are presently reading is pink in color

Journey of BC: Diagnosis

1. I feel a lump! - The first visit to doctor
2. Is it really cancer? - Confirmatory tests
3. What is the stage? - Staging and fitness tests
4. Will it be surgery first? or chemo first? - Treatment planning and sequence

Journey of BC: Surgery

5. Should I conserve or remove breast? - Choice of Surgeries for breast cancer
6. How long will be the surgery? - Admission and Surgery
7. Care after surgery - Precautions and guidelines
8. What next? - The Pathology Report

Journey of BC: Further Treatment

9. How many chemo cycles? - Chemotherapy Consultation
10. Is a PORT necessary? - ChemoPORT insertion
11. Will I be normal during chemo? - The Chemotherapy time
12. Is Radiation painful? - Radiation Therapy
13. Yes!! I did it! - Treatment is over
14. How frequently do I meet doc? - Follow up guidelines

Other Topics

Risk Factors - The Risk Factors for Breast Cancer. You are presently on this page
Symptoms of Breast Cancer - Know the Symptoms of Breast Cancer
Early Detection of Breast Cancer - The Guidelines

Neo Adjuvant Chemotherapy (NACT) - For LABC
Sentinel Node Biopsy - How is it done?
Targeted Therapy - Trastuzumab
Hormone Therapy - Who gets it?