Introduction: The routine use of sentinel node biopsy (SLNB) at the time of prophylactic mastectomy remains controversial. This retrospective study was undertaken to determine if SLNB is justified in patients undergoing CPM.
Methods: Between 1999 and 2004, 155 patients underwent contralateral prophylactic mastectomy (CPM) at the Magee-Womens Hospital of University of Pittsburgh Medical Center. Eighty patients (51.6%) had SLNB performed at the time of CPM. The therapeutic mastectomy and the CPM specimens were evaluated for histopathology. Goldflam's classification was used to determine the risk of malignancy in the CPM specimens.
Results: Pathology in the therapeutic mastectomy specimens included 105 (68%) invasive carcinomas and 50 (32%) in-situ carcinomas. Multicentricity and/or multifocality were reported in 49.7%, and 70% were estrogen receptor positive. Two invasive breast cancers and three cases of DCIS were diagnosed in 155 CPM specimens (n = 5, 3.2%). The median number of SLN identified was 2 (range 1-6) from the CPM axilla. Two patients had positive SLNB for metastatic carcinoma (n = 2/80, 2.5%) with no primary tumor identified in the prophylactic mastectomy specimen. In both patients the therapeutic mastectomy was for recurrent invasive carcinoma in patients with a prior history of axillary node dissection. Occult carcinoma was found in five prophylactic mastectomy specimens: two invasive and three DCIS. Only 1 out of the 75 patients not undergoing SLNB at the time of their initial surgery would have required axillary staging for a previously undiagnosed invasive cancer in the CPM specimen on final pathology. Of all 155 patients undergoing CPM, only 4 (2.5%) had identified final pathologic findings where axillary staging with SLNB was beneficial. There was no evidence of arm lymphedema in any patient who had undergone CPM and SLNB at a median follow-up of 24 months.
Conclusion: Although SLNB is a minimally invasive method of axillary staging, this retrospective study does not support its routine use in patients undergoing CPM.