Breast cancer is one of the most common cancer affecting women, it has been estimated that one in every eight women will be diagnosed of breast cancer. Every year there is alarming increase in number of breast cancer cases, and it has become a major public health problem.
What are the risk factors for Breast cancer?
# Family history: Family history remains an important risk factor to be considered in assessing the risk of women developing breast cancer. Both maternal and paternal family history should be considered while evaluating the risk.
The risk increases if there are two or more family members diagnosed with breast cancer, any one relative with breast cancer diagnosed before the age of 50, relative diagnosed with ovarian cancer.
Strong family history points towards inherited predisposition of breast cancer caused by mutation in various genes like BRCA1/2, P53, PTEN.
#Hormonal Factors: Estrogen hormone present in women is essential for proper menstrual cycle and also for reproductive function. It is strongly associated with risk of developing breast cancer. Risk is increased in women who had early menarche, nulliparity, first child birth after the age of 30, late menopause. Women taking oral contraceptive pills are also at increased risk of breast cancer.
Pregnancy and breast feeding for atleast one year has been shown to reduce the risk of breast cancer.
#Dietary and Lifestyle Factors: In lieu of sedentary life style many women are now becoming obese. Obesity is presently also affecting women of developing nations. Women with high body mass index BMI (calculated according to the weight and height) have significantly higher risk of developing breast cancer. It has been estimated that women with BMI 31.1 have 2.5 fold higher risk of developing breast cancer as that of women with BMI ≤ 22.6. Excess fat leads to increase in estrogen level in body, due to peripheral conversion and this is reason for risk of developing breast cancer.
Alcohol consumption one the risk factor for developing breast cancer. Women who drink daily have higher risk.
#Breast Biopsy: Breast biopsies performed to rule out breast cancer has also been shown to be risk for developing breast cancer, specifically if the biopsies had LCIS, ADH or ALH.
#Dense Breast: Women undergoing screening mammography and found to have a dense breast are also at risk of developing breast cancer.
#Radiation Exposure: Radiation exposure to chest wall in childhood is associated with elevated breast cancer risk. Women exposed to radiation before the age of thirty fall in that category.
Complete risk assessment for breast cancer can be done using modified GAIL model. It is computer generated system where life time risk of developing breast cancer can be assessed. Women with lifetime risk of more than 20% need to undergo risk reducing therapy to mitigate the risk of breast cancer.