In situ breast cancer.

The clinical expression of in situ cancer varies widely but is usually occult. Diagnosis can be made by a variety of minimally invasive techniques. Treatment of lobular carcinoma in situ (LCIS) is patient-directed but generally requires only close follow-up. Mastectomy is the gold standard for ductal carcinoma in situ (DCIS) and is associated with low recurrence rates. Breast conservation therapy (BCT) has become an acceptable alternative. This choice of definitive therapy for DCIS depends largely on the ability to obtain negative margins. Any attempt at BCT should be coupled with the caveat of close postoperative long-term follow-up. Patients diagnosed with LCIS or who have a history of DCIS should be given the options for the use of tamoxifen for the reduction of subsequent development of invasive breast cancer. Risk versus benefits should be clearly defined.