Physical activities such as walking can reduce the risk of developing breast cancer by lowering the estrogen levels  Dr Reonald Kayonde, the head of cancer department in Rwanda Biomedical Centre, says several studies in the field have proved that women who engage in regular exercise have minimal chances of getting breast cancer."Exercise reduces total body fat, may change the internal makeup of a woman’s body and make it harder for breast cancer to take hold,” Dr Kayonde says.He added that higher estrogen levels comes from fat tissue after menopause and having more fat tissue raises estrogen levels and in turn breast cancer risk."Exercise may be as effective as medication in treating common diseases such as heart disease and diabetes, breast cancer; and has benefits for obesity prevention,” the medic says.According to Dr Kayonde, being overweight increases the risk of breast cancer, so women should control over weight, physical activity can help you maintain a healthy weight most especially in health adults, to spend at least 75 minutes a week practicing aerobic activity. Breastfeeding helping breast cancer prevention, because longer you breast feed, the greater the protective effect, hormonal changes occur during pregnancy changes that, may increase a women`s chances of developing breast cancer in her life.Dr Kayonde says there are two types of cancer; Ductal carcinoma in intraductal carcinoma is breast cancer in the lining of the milk duct that has not yet invaded nearby tissues. It may progress to invasive cancer if not treated. Lobular carcinoma in situ is a marker for an increased risk of invasive cancer in the same or both breasts, Dr Kayonde said.