How to identify patients with increased risk of breast cancer relapse?

A cohort of 362 breast cancer patients had subtype classification accomplished using 4 immunohistochemical markers: luminal A (ER or PR positive, HER2 negative, Ki-67<14%), luminal B (ER or PR positive, HER2 negative, Ki-67≥14%), luminal HER2 (ER or PR positive, HER2 positive), HER2 enriched (ER or PR negative, HER2 positive) or triple negative (ER, PR, and HER2 negative). Multivariable Cox analysis was used to determine the risk of local (LR) or distant (DR) relapse associated with the intrinsic subtypes, adjusting for standard clinicopathologic factors. There have been a total of 124 recurrences. Triple-negative patients were associated with increased risk of LR. Luminal B subtype showed statistical tendency (P=0.053) to LR. For patients undergoing breast conservation surgery, luminal B and HER2-enriched subtypes demonstrated an increased risk to LR, and this was statistically significant on multivariable analysis. After mastectomy, there was no statistical difference between subtypes of LR or DR on multivariable analysis. Luminal A tumors are associated with a low risk of LR or DR. Despite the existence of gene expression profiling, in the current study we demonstrate that analysis of 4 immunohistochemical markers is equally effective and less expensive alternative to identify higher recurrence risk patients.