The role of sentinel lymph node biopsy in women undergoing prophylactic mastectomy.

Background: Indications for prophylactic mastectomy (PM) range from LCIS to BRCA 1-2 positive, cosmesis, and cancer phobia. Occult cancers have been found in up to 5% of PM cases. Consequently, consideration must be given to the role of sentinel lymph node (SLN) biopsy as a diagnostic procedure in these patients as PM excludes the subsequent option of SLN biopsy.

Methods: From April 1994 to November 1999, all patients undergoing PM had SLN biopsy after four quadrant periareolar injections of radiocolloid (450 mci) and blue dye (5 cc). All patients were prospectively accrued to the computerized database of breast patients. The SLN were all evaluated with hematoxylin and eosin (H&E) as well as CAM5.2 cytokeratin immunohistochemical (CK-IHC) stains.

Results: Over a 67-month period, 1,356 patients were mapped; 57 patients underwent PM in which 148 nodes (2.6 nodes per patient) were evaluated. Nodes were examined by routine H&E and CK-IHC staining. Two patients, neither of whom was found to have a cancer in the prophylactic mastectomy breast, were found to have a positive SLN by CK-IHC staining. Infiltrating carcinoma was discovered within the PM breasts of 2 additional patients. Sentinel lymph node biopsy was negative for malignancy by H&E as well as CK-IHC stains. No lymphedema has been detected in PM patients.

Conclusions: Sentinel node biopsy has been shown to be an accurate and minimally invasive method of evaluating the lymphatic basin. This study shows that the absence of known disease within the breast does not preclude the presence of occult cancer or metastatic nodal disease. Four patients (7%) had a significant change in their surgical management as a direct result of sentinel lymph node biopsy. Two patients were spared the complications of a complete axillary node dissection. This minimally invasive procedure accurately evaluated the known disease status and provided new diagnostic information. Most important, once a mastectomy is performed, the opportunity for SLN biopsy is lost should a cancer be found within the breast specimen.