Assessment of the prognostic and predictive utility of the breast cancer index (BCI): An NCIC CTG MA.14 study.

561 Background: Breast Cancer Index (BCI), a continuous risk index, combines the ratio of HOXB13 to IL17BR (H/I) and the molecular grade index (MGI) (Jerevall et al., British J Cancer, 2011). Here, the prognostic and predictive performance of BCI for BC relapse in MA.14 trial was examined. Methods: MA.14 randomly assigned 667 hormone receptor positive (HR+) women to 5 years of tamoxifen (TAM) +/- 2 years of octreotide LAR (TAM-OCT). A representative subgroup of 299 patients was profiled by RT-PCR for BCI. The primary objective was to determine the prognostic performance of BCI based on relapse-free survival (RFS) with median 9.8 years follow-up. Association of BCI was assessed with step-wise forward stratified Cox regression. Pre-defined categories of low (L), intermediate (I) and high (H) BCI risk groups were used to provide adjusted 5- and 10-year RFS. Results: 292 of 299 patient samples passed internal analytical quality control. The 292 patients contained 49% LN+ patients and had 19.9% BC relapses. Bo...