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, P = .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.