Metastatic Colorectal Cancer in Hispanics: Treatment Outcomes in a Treated Population

Abstract

Background: In United States Hispanics have disparities in the presentation and outcome of colorectal cancer (CRC) largely attributed to their late presentation and lower socioeconomic status. Impact of treatment, especially in the metastatic setting, in the observed outcome is an unexplored area. We explored the role of treatment in the outcome of metastatic CRC we performed a retrospective analysis to assess the contribution of demographics, tumor characteristics, and health care setting on survival differences.

Patients and methods: We conducted a retrospective study of patients who were treated with metastatic CRC at Los Angeles County Hospital-University of Southern California (LAC-USC, a public hospital) and Norris Comprehensive Cancer Center (NCCC, private hospital) between 2002 and 2012. Both these institutions are staffed by the same providers and therefore treatment algorithms and access to drugs were similar. We identified metastatic CRC patients who received chemotherapy from administrative records. Demographics, tumor, and treatment related factors were collected. The primary end point was time to progression (TTP: time from the first day of chemotherapy to the date of progression). Overall survival (OS) was measured from the first day of chemotherapy to death or last follow-up. Descriptive statistics were used to describe the population and chi-square, Wilcoxon, and log-rank tests were used for comparison between the groups.

Results: A total of 242 patients, 44% Hispanic, 26% non-Hispanic whites (NHWs), 21% Asian and 9% black were included. Median TTP was 9.2 months (95% confidence interval [CI], 7.6-11.6) in Hispanics, and 20.7 months (95% CI, 9.6-27.5; P < .05) in NHWs. Median OS in Hispanics was 16.3 months (95% CI, 13.3-18.5), and in NHWs was 33.5 months (95% CI, 22.1-63.6; P < .001). Hispanics who were treated at LAC-USC had longer TTP in comparison to Hispanics at NCCC (P = .04).

Conclusion: Hispanics with metastatic CRC have shorter TTP and OS on first line therapy when adjusted for health care setting, demographics, disease characteristics, and treatment factors.

Keywords: Colorectal cancer; Hispanics; Outcomes; Racial disparities; Survival.

Figure 1. Mortality Rate From Colorectal Cancer in US Population

Vertical column represents number of deaths per 100,000 population. Data from Siegel R, Desantis C, Jemal A. Colorectal cancer statistics, 2014. CA Cancer J Clin 2014;64:104–17.

Figure 2

Time to Progression and Survival by Ethnicity. (A) Kaplan-Meier Curve of Time to Progression for Hispanics and Non-Hispanic Whites in Entire Study Population. (B) Survival of Hispanics and Non-Hispanics in Study Population. Log-Rank P Values and Number of Patients are Shown