Effectiveness of Biologic Agents Among Hispanic Patients With Metastatic Colorectal Cancer

Background

Randomized clinical trials have defined the survival advantage with the addition of biologic drugs to chemotherapy in patients with metastatic colorectal cancer (mCRC). Under representation of Hispanics contributes to poorly defined outcomes in this group. We aim to determine whether the real-world benefit of biologics extends to Hispanics using a comparative effectiveness research approach.

Methods

This retrospective cohort study included all treatment centers contributing to SEER registry with available claims in the SEER-Medicare linked database (2001-2011) and 2 hospitals (2004-2016) catering to minorities. Metastatic CRC patients were classified as receiving chemotherapy or biochemotherapy (CT plus biologics; if initiated within 3 months of chemotherapy). The primary outcome was overall survival (OS) among the Hispanic patients calculated from time of administration of first dose of chemotherapy to death or last follow-up. A weighted Cox regression model was used to assess differences in survival.

Results

We identified 182 Hispanic patients with mCRC from the Patient Entitlement and Diagnosis Summary (PEDSF) file (n = 101) and hospital database (n = 81). Overall, 52% were women and 72% received biologics. The median OS was 11.3 and 17.0 months in chemotherapy and biochemotherapy group, respectively. Biochemotherapy offered a survival benefit compared with chemotherapy alone, with an average hazard rate reduction of 39% (95% CI 6%-60%, p = .0236) using inverse probability of treatment weighting (IPTW) based analysis.

Conclusion

In this cohort of Hispanic patients with mCRC, biochemotherapy was associated with longer survival. Clinicians may offer biochemotherapy therapy to all patients regardless of race/ethnicity to maximize clinical benefit.