Therapy of in situ cancer.

In situ carcinoma of the breast is divided into ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS). These two entities have different morphologic appearances and natural histories. The traditional treatment of DCIS has been mastectomy, which has been shown to yield a very high cure rate. Other options include excision with or without radiotherapy. Preliminary evidence suggests that these techniques can be successful in the great majority of patients, with most treatment failures being manageable by salvage mastectomy. Careful observation of these patients appears associated with a low risk of breast cancer mortality and is generally the recommended policy.