Cancer is a group of diseases that are characterized by abnormal cell growth in certain parts of the body. Based on the location they occur within the body and their type, there are over 100 types of cancers that affect humans. These cells have the potential to invade or spread to other parts of the body.
Breast cancer is cancer that develops from the breast tissue. About 5 – 10% of breast cancers are caused due to genetic reasons. Breast cancer usually develops in cells from the lining of milk ducts and the lobules that supply milk to the ducts. Based on where cancer develops from, there are two types of breast cancers – lobular carcinoma and ductal carcinoma.
- Lobular carcinoma – a type of cancer develops from the lobules.
- Ductal carcinoma – cancer developing from ducts is called ductal carcinoma.
- Besides these two, there are 18 other common types of breast cancer.
Breast cancer stands to be the most common invasive cancer in women, affecting about 12 % of women worldwide. About 22.9 % of all cancer cases are of breast cancer. The incidence of breast cancer is low in women aged less than 40 years, with only 5% of them being affected. This is because of the denser breast tissue.
In the developed countries, the survival rates for breast cancer are high, ranging between 80 – 90%. The survival rates are poor in developing countries.
In India, breast cancer is ranked number one cancer among women with an age-adjusted rate as 25.8 per 1 lakh women. Cervical cancer was earlier the most common cancer in Indian women, but breast cancer has taken over lately. Breast cancer is also the leading cause of death in women in India. In northeast India, breast cancer ranks top. By 2020, the number of breast cancer cases is likely to double in number.
Factors like betel quid, tobacco chewing, number of children, age at marriage, age at first childbirth, and age at menarche have proven to increase the risk of developing breast cancers. Longer menstruation periods due to late menopause are also associated with an increased risk of breast cancer.