How is breast cancer treated?

Surgery/Chemo/Radiat. Treatment usually starts with surgery, removal of the tumor grossly. Depending on the stage and biology it may require chemotherapy and/or radiation. Anti-estrogen therapy may also play a role.
Depens (penicillamine) on stage. This depends on the stage. But generally breast cancer is treated by multiple specialities. Surgery, chemo, hormonal, and radiation are the main treatment modalities.
Stage, biology of ca. Treatment of breast cancer will depend on the stage, the biology of cancer, prognostic factors, your overall condition and your preference. There are 3 modalities that are used- many times- used in combination - surgical resection ( lumpectomy vs. Mastectomy); radiation therapy and chemotherapy and/or hormonal tx ( anti estrogen therapy), and biological ts. Treatment is complex and individualized.