Some of the cancers that most often affect women are breast, colorectal, endometrial, lung, cervical, skin, and ovarian cancers. Knowing about these cancers and what you can do to help prevent them or find them early (when they are small, haven't spread, and might be easier to treat) may help save your life.Breast cancer is the most common cancer in American women, except for skin cancers. It can occur at any age, but the risk goes up as you get older. Because of certain factors, some women may have a greater chance of having breast cancer than others. But every woman should know about the risks for breast cancer and what they can do to help lower their risk.