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Hispanic race and outcome of metastatic (MET) colorectal cancer (CRC): Biology or health care (HC) setting?
Abstracts that were granted an exception in accordance with ASCO's Conflict of Interest Policy are designated with a caret symbol (^).
Background: Hispanics (H) have lower CRC related mortality compared to Whites (W). However, over the past decade H have appreciated less improvement in CRC mortality. Given that treatments (TX) for early stage CRC is unchanged we speculate that the gap is due to poorer outcome in the MET setting. Delivery of HC is identified as one of the factor for poor outcomes. We examined the relationship between HC delivery (public or private hospital) and TX as the drivers of poorer outcome in H. Methods: We identified CRC patients (pts) with at least one cycle of chemotherapy (CT) in the first line MET setting at Los Angeles County Hospital (LAC-public hospital) and Norris Cancer Center (NCC-Private hospital) between 2004-2011. Demographics; tumor and TX related factors were collected. Primary endpoint was TTP (time from first day to progression on first line CT). Descriptive statistics were used to describe the population and where appropriate chi-square, Wilcoxon, and log-rank tests were used for comparison between the groups. Results: 251 pts, 45%H, 26%W, 20% Asian (A) and 9%Black (B) were included. The median age of the population was 55 (21-82) years. 55% of pts were male.74 % of pts had de-novo MET disease. 48% of pts had left sided, 27% right sided and 25% rectal cancer. 71% of pts treated at LAC and 29% at NCC. 46% of pts at LAC and 56% at NCC received bevacizumab (BEV) as part of their TX (p= 0.26). Median TTP in H was 10.2 months (m) (95% CI: 8.1-11.8), and in W was 16.8 m (95% CI: 11.2-27.2; P<0.05). Hispanics who were TX at LAC had longer TTP in comparison to H at NCC (p= 0.01). In multivariate analysis, race remained a significant predictor of TTP (p=0.001). Conclusions: H are the largest and fastest growing minority in the US, identification of factors of disparate outcome is crucial. This study revealed a significant association between race and TTP. Use of BEV for MET CRC became a standard TX in 2004 and since then TX is mostly unchanged. Our cohort received homogenous TX with regards to use of BEV. The results show that H regardless of HC setting have shorter TTP than W suggesting an inherent biological difference in the tumor or response to TX. Future biomarker studies will shed light on the cause.