Molecular profiling using breast cancer subtype to plan for breast reconstruction.

BACKGROUND: Molecular profiling using breast cancer subtype has an increasing role in the multidisciplinary care of the breast cancer patient. We sought to determine the role of breast cancer subtyping in breast reconstruction and specifically if breast cancer subtyping can determine the need for postmastectomy radiation therapy (PMRT) and predict recurrence-free survival (RFS) to plan for the timing and technique of breast reconstruction.

METHODS: We reviewed prospectively collected data from 1931 reconstructed breasts in breast cancer patients who underwent mastectomy between November 1999 and December 2012. Reconstructed breasts were grouped by breast cancer subtype and examined for covariates predictive of RFS and need for PMRT.

RESULTS: Of the reconstructed breasts, 753 (39%) were luminal A, 538 (27.9%) luminal B, 224 (11.6%) luminal HER2, 143 (7.4%) HER2 enriched, and 267 (13.8%) TNBC. PMRT was delivered in 69 (48.3%) HER2 enriched patients, 94 (42%) luminal HER2, 200 (37.2%) luminal B, 99 (37.1) TNBC, and 222 (29.5%) luminal A (p < 0.0001). Luminal A cases had better RFS than HER2 enriched cases, and TNBC cases had worse RFS than HER2 enriched cases. Luminal B and Luminal HER2 cases had RFS similar to that for HER2 enriched cases. Luminal A subtype was associated with the best RFS. Subtyping may have improved the breast surgery planning for 33.1% of delayed reconstructions that did not require PMRT, and 37% of immediate reconstructions that did require PMRT.

CONCLUSION: This study is the first publication in the literature to evaluate breast cancer subtype to stratify risk for decision making in breast reconstruction.