Breast Cancer is the most common cancer in Indian women and accounts for 27% of all cancers in women. About 1 in 28 women are likely to develop breast cancer during their lifetime. In the urban areas the incidence is 1 in 22 as compared to the rural areas where 1 in 60 women develop breast cancer. The incidence begins to rise in the early thirties and peaks at the age of 50 – 64 years.
What Causes Breast Cancer?
The exact cause of breast cancer is not known. However, several factors affect our risk of developing breast cancer. The chances of developing the disease depends on a combination of our genes and bodies, lifestyle, life choices and the environment.
Being a woman and age are the two biggest risk factors.
Being a Woman
Women are much more likely to get breast cancer than men, so simply being a woman means you are at higher risk of developing the disease.
As you get older, your risk of breast cancer increases. The highest incidence is in women over the age of 50.
For women, being taller slightly increases the risk of developing breast cancer. Conversely, being shorter slightly decreases risk.
Women who started their periods at an early age have a slightly increased risk of breast cancer. The earlier you began your periods, the higher your risk, but this effect is small and gradual. The increase in risk is probably because of the longer exposure to the female hormone estrogen.
In a small number of women, breast cancer runs in the family. Of all women who develop breast cancer, up to 15% has a significant family history of the disease and about one in 20 has inherited a fault in a gene linked to breast cancer. Women who have inherited faults in known breast cancer genes such as BRCA1 or BRCA2 are at increased risk of developing breast cancer.
High Breast Density
The amount of tissue compared to fat in your breasts is known as ‘breast density’. Having high breast density (a low proportion of fat) is one of the biggest risk factors for breast cancer. The density of your breasts tends to gradually fall over time, but because age is also a risk factor for breast cancer, this does not mean that your risk of breast cancer reduces as your breasts change. In fact, your risk of breast cancer increases as you get older.
Women who go through the menopause later than average have a slightly increased risk of breast cancer. The later you go through menopause, the higher your risk, but this effect is small and gradual. The increase in risk of breast cancer seen in women who have a late menopause is probably because these women are exposed to the female hormone oestrogen for longer than women who go through the menopause earlier.
A white woman is more likely to develop breast cancer than a black, Asian, Chinese or mixed-race woman.
Ashkenazi Jews and Icelandic women have a higher risk of carrying inherited faults in breast cancer genes, such as BRCA1 or BRCA2, which are known to increase the risk of developing breast cancer.
Unfortunately, there is nothing that you can do to change the above risk factors. But all women should be breast aware – this means knowing what is normal for you so that you are aware as soon as something changes. The sooner you notice a change the better, because if cancer is found early, treatment is more likely to be successful. Get into the habit of looking at and feeling your breasts from time to time. This will help you to notice any change if it occurs.
Life Choices, Lifestyle and Environment
Factors that increase the risk of breast cancer are: Weight gain, lack of exercise, alcohol, hormone replacement therapy, the combined oral contraceptive pill, ionizing radiation, radiotherapy, stress and possibly shift work.
Pregnancy and Breastfeeding reduce the risk. Age and number of pregnancies affect the risk. The earlier the pregnancies and the more the number of pregnancies, the lesser is the risk of cancer.
Breastfeeding slightly reduces your risk of breast cancer and the longer you breastfeed, the more your risk of breast cancer is reduced. Breastfeeding may reduce breast cancer risk by altering the balance of hormones in the body and by delaying the return of your periods.
The cause of breast cancer is not known. Hence it is not known if it can be prevented completely. Although there are no definite conclusions, there are benefits for women who exercise regularly, maintain a healthy weight, do not smoke and have a low intake of alcohol.
Breast cancer cannot be prevented, however if it is detected early it is easier to treat. In the past breast self-examination was advocated to help pick up cancer early. However, breast exams are no longer a part of the screening recommendations because research does not show they provide a clear benefit. Still, the American Cancer Society says all women should be familiar with how their breasts normally look and feel and report any changes to their doctor immediately. Mammograms are advocated as screening procedure to pick up early cancer. These can be done from the age of 50 onwards at regular intervals as recommended by your doctor.