Breast cancer happens when normal cells in the breast change and grow out of control.Breast cancer is the most common cancer in women, both in developed and developing countries. Once considered a disease common mainly in developed countries, currently almost 50 per cent of breast cancer cases and 58 per cent of deaths from breast cancer occur in developing countries. Incidence rates vary greatly, with higher incidences in developed countries although the incidence rates in developing countries are on the rise.

Survival rates after diagnosis of breast cancer varies worldwide, ranging from 80 per cent in some developed countries to below 40 per cent in developing countries. The low survival rate in developing countries is greatly attributed to late detection where patients present with late stage disease.

Breast cancer is usually discovered when individuals coincidentally feel swellings within their breasts and at times these swellings are ignored for a long time since they rarely cause symptoms initially.

If these swellings are cancerous, they grow and spread to the surrounding tissues and at times to distant organs and by the time the individual goes to hospital for checkup, the cancer is advanced and this makes the treatment outcome poor.

Early detection of breast cancer in order to improve the treatment outcome, hence more chances of survival, remains the mainstay of breast cancer control.

A breast lump or swelling should never be ignored although most breast lumps are known to be non-cancerous.

Breast cancer is much more common in women than in men although men can suffer from it as well.

Risk factors for breast cancer

Increasing age is the primary risk factor for breast cancer in most women. The incidence of breast cancer rises sharply with age until the age of 45 to 50, at which point the rise is less steep. At age 75 to 80, the incidence rates flatten out and then start to decline after this.

Breast cancer is the most common cancer in women worldwide and occurs 100 times more commonly in women than in men.

White women have the highest rate of breast cancer and black women a lower risk of developing breast cancer.

Reproductive factors

Both a younger age when menses begin and a later age at onset of menopause (cessation of menses) increase the breast cancer risk which is likely due to the overall exposure to estrogen hormone in a woman’s lifetime and women who have never given birth are more likely to develop breast cancer after menopause than women who have given birth multiple times.

In addition, the younger a woman is at her first full-term pregnancy the lower her risk of breast cancer. Breastfeeding has been found to be protective against developing breast cancer.

Women with a previous history of cancer in one breast have an increased risk of developing cancer in the other breast.

Family history is an important risk factor for breast cancer. One of the main factors responsible for this elevated risk is an inherited genetic mutation in one of two genes, called BRCA1 and BRCA2. For women who have a BRCA1 or BRCA2 mutation, the lifetime risk of breast cancer ranges from 50 to 85 percent but this is not common, with less than 10 percent of all breast cancers associated with inherited genetic mutations.

Use of postmenopausal hormone replacement therapy for a long time is associated with an increased risk of developing breast cancer

Lifestyle factors such as sedentary lifestyle, smoking, alcohol consumption, obesity, excessive consumption of red meat (more than 5 meals of red meat per week) increase the risk of breast cancer.

It is, however, important to know that presence of breast cancer risk factors does not mean that cancer is inevitable. Many women with risk factors never develop breast cancer. Instead, risk factors help to identify women who may benefit most from screening or other preventive measures. Breast cancer can also occur in women who have no identifiable risk factors.

The average woman has about a 10 to 15 per cent chance of developing breast cancer if she lives into her 90s. On the other hand, the risk of developing breast cancer in a woman with a strong family history of the disease who has inherited one of the genes that predispose her to breast cancer is over 50 per cent.

Early detection mainstay of outcome and breast cancer control

Breast cancer screening includes tests to detect breast cancer at an early stage. The chance of dying from breast cancer has declined by about a third over the past few decades. This is partly attributed to the use of breast cancer screening to find cancer at an earlier stage. Breast cancer is more likely to be cured when it is caught earlier.

There are three main ways to screen breast cancer: breast mammogram, breast exam by a clinician, and breast self-exam. A mammogram is a breast x-ray and is the best screening test for reducing the risk of dying from breast cancer. An abnormal mammogram result doesn’t mean that one has breast cancer, and in fact 90% of the abnormal results aren’t cancerous and hence more tests are carried out.

Screening with mammogram is recommended at the age of 45 years and to done annually until the age of 54 years, after which it is done after every 2 years. In women at higher risk of breast cancer, mammogram screening can begin at 40 years. This of course has cost challenges

Routine clinical examination and self-examination should be done though these have many limitations. Self-breast examination to feel for any breast lumps, skin changes, nipple changes should be done monthly and preferably a week after menses, if one is still experiencing periods.

Treatment options for cancer of the breast depend on how far the cancer has spread. It may involve surgery to cut out the cancer alone, or the breast, radiation therapy which kills cancer cells, chemotherapy or hormonal therapy. One or combination of these can be used depending on the stage of the cancer.

Dr Ian Shyaka is a General Practitioner based in Kigali