Incremental risk associated with contralateral prophylactic mastectomy and the effect on adjuvant therapy.

BACKGROUND: Contralateral prophylactic mastectomy (CPM) is expected to add surgical morbidity but this incremental risk has not yet been defined. We sought to quantify the additional risks associated with CPM and determine how these risks influence the time to adjuvant therapy.

METHODS: We identified women undergoing mastectomy for unilateral breast cancer and stratified them according to the use of CPM and the presence and laterality of surgical complications. We measured time to adjuvant therapy.

RESULTS: Of 352 patients, 205 (58 %) underwent unilateral mastectomy (UM) and 147 (42 %) underwent bilateral mastectomy (BM) [BM = UM + CPM]. Overall, 94/352 (27 %) women suffered 112 complications (BM: 46/147 [31 %] vs. UM: 48/205 [23 %]; p = 0.11), of which hematoma, skin necrosis, cellulitis, or seroma accounted for 94/112 (84 %) complications. Reoperation was required in 37/352 (10 %) women. Among those undergoing BM, morbidity occurred only in the prophylactic breast in 19/147 (13 %) women and risk did not differ with immediate reconstruction (13/108 [12 %]) or without (6/39 [15 %]). Of these 19 patients, 10 (53 %) required reoperation. Women with any complication had a longer interval to adjuvant therapy when compared with those without (49 days vs. 40 days; p < 0.001). When stratified according to side, complications in the prophylactic breast were not associated with a delay in treatment (UM: 58 days vs. BM: prophylactic side; 41 days vs. BM: cancer side: 50 days; p = 0.73).

CONCLUSIONS: CPM confers additional morbidity in one in eight women, of whom half require reoperation. Despite this, in our series CPM did not delay adjuvant therapy. Given the rising incidence of patients seeking CPM, they should be informed of this risk.