This mass of tissue is called a tumor. Any change in the breast, including a thickening or swelling in a local area that wasn't there before, may be a tumor. Many women will experience a benign tumor at one time or another. Benign tumors are not a threat to life, and can usually be removed. Unlike benign tumors, cancerous tumors continue to grow in an uncontrolled way and in time will spread beyond the breast.
Malignant tumors require treatment.
All women are at risk of developing breast cancer. If however, you fit into any of the following groups your chances of developing cancer are greater. Women in the High Risk group should be especially careful to have periodic breast examination by their physicians and to practice breast self examination every month. If any of the signs of breast cancer are present, you should see a physician as soon as possible. Once a month, every woman should take the time to examine her breasts for changes in breast tissue.