Minimally Invasive Mastectomy Could Achieve Non-inferior Oncological Outcome in Appropriately Selected Patients: Propensity Matched Analysis of the National Cancer Database.

Background: Minimally invasive mastectomy (MIM) was emerged as an approach to decrease morbidity and increase patient satisfaction through improved cosmetic results; however, there is a paucity of data regarding the long-term oncologic outcomes of these minimally invasive approaches.

Methods: Patients who underwent mastectomy procedures were identified in the National Cancer Database (2010-2016). Patients were categorized as MIM or open mastectomy. A 1:1 propensity match was performed to balance the bias on reconstruction, nipple sparing, lymph node procedures, and other confounding factors between the cohorts. Short- and long-term outcomes were compared.

Results: A total of 328 811 patients met the criteria: 327 643 (99.6%) received open mastectomy and 1168 (.4%) received MIM. Propensity match identified 384 "pairs" of MIM and open mastectomy patients. Among them, MIM was associated with shorter length of stay (LOS) (mean 1.3 vs. 1.06 days, = .003). No differences were observed in the rates of positive margins, unplanned readmissions, or 90-day mortality between the 2 operative approaches. Overall survival (OS) was equivalent between MIM and open mastectomy patients. Cox proportional hazard regression showed no effect of the procedure performed on OS.

Discussion: MIM is associated with shorter LOS, and it is non-inferior to open mastectomy in terms of other short-term outcomes and long-term oncologic survival outcomes. These data suggest that MIM may be considered in appropriately selected breast cancer patients as an additional approach to the community.