* CASES: An estimated 119,000 new cases in the United States this year. About 1 out of 11 women will develop breast cancer at some time in their lives.

* MORTALITY: An estimated 38,400 deaths in 1985. The leading cancer killer in women.

* WARNING SIGNALS: Breast changes that persist, such as lumps, thickening, swelling, nipple changes, pain or tenderness.

* RISK FACTORS: Over age 50; personal or family history of breast cancer; never had children; first child after age 30.

* EARLY DETECTION: Monthly breast self-examination by women over age 20. The National Cancer Institute recommends routine mammography -- a low-dose, X-ray exam -- for women in high risk categories, including those over 50, age 40 or more with a family history of breast cancer, and 35 or more with a personal history of breast cancer. Regular professional breast examinations are also recommended.

* TREATMENT: Several methods may be considered, depending on a woman's preferences and her medical situation. Surgery varies from local removal of tumor to removal of the whole breast, with other therapies often used in combination with surgery. New study suggests that about half of new breast cancer patients -- particularly those with smaller tumors -- may be candidates for local surgical removal of tumor, in combination with radiation therapy. Chemotherapy also may be recommended for those whose cancer is detected in the lymph nodes.

* SURVIVAL: Five-year survival for all women with breast cancer is 74 percent. For women whose tumors are small and localized in the breast at time of diagnosis, the rate jumps to 96 percent. Breast cancer, however, can recur after five years.

* FOR MORE INFORMATION: Call National Cancer Institute hotline, 800-638-6694* (except in Maryland, call 800-492-6600*) or write National Cancer Institute, Office of Cancer Communications, Bethesda, Md. 20205. Or contact local chapter of American Cancer Society.