Safety and effectiveness of oxaliplatin-based chemotherapy regimens in adults 75 years and older with colorectal cancer

Abstract

Although the safety and efficacy of oxaliplatin-based chemotherapy regimens for colorectal cancer (CRC) have been demonstrated in adults > 75 years of age enrolled in clinical trials, safety and effectiveness outside the trial setting are less established. In this comparative effectiveness study, we note that older adults with stage III and metastatic CRC treated outside of a clinical trial experienced safety and effectiveness of oxaliplatin-based chemotherapy regimens comparable to that of younger adults.

Background: Although the safety and efficacy of oxaliplatin-based chemotherapy regimens for colorectal cancer (CRC) have been demonstrated in adults ≥ 75 years of age who are enrolled in clinical trials, safety and effectiveness outside the trial setting are less established.

Methods: We retrospectively collected cases of patients ≥ 75 years of age who were diagnosed with stage III and metastatic CRC and initiated treatment between January 2000 and January 2007 at 2 academic hospitals in Boston, MA. Cases were matched in a 1:2 ratio to controls who were < 75 years of age by hospital site, stage of disease (stage III vs. metastatic) and line of therapy (first- or second-line or beyond). The primary study endpoints were grade ≥ 3 treatment-associated toxicities and intolerance (number of dose delays/reductions and hospital/facility admissions during treatment). The secondary endpoint was overall survival.

Results: We identified 84 patients ≥ 75 years of age (25% ≥ 80 years) and 168 controls. In the cohort, 77% had colon cancer, 75% had metastatic disease, and 60% were receiving oxaliplatin as first-line therapy. There was no significant difference in grade ≥ 3 treatment-associated toxicities between the patients and the controls (71.4% vs. 68.5%, respectively; P = .63). Further there was no statistically significant difference between patients and controls for combined endpoints of any grade ≥ 3 toxicity or hospital/facility admission (P = .92). With a median follow-up of 52 months, 2-year overall survival was similar between patients and controls (43% vs. 52%, respectively; P = .87).

Conclusion: Older adults with stage III and metastatic CRC treated outside of a clinical trial experienced safety and effectiveness of oxaliplatin-based chemotherapy regimens that was comparable to that of younger adults.