Adjuvant Chemotherapy for Older Patients With Stage III Colorectal Cancer: A Real-World Analysis of Treatment Recommendations, Treatment Administered and Impact on Cancer Recurrence

Abstract

Background

A substantial proportion of patients with stage III colorectal cancer (CRC) are older than 70 years. Optimal adjuvant chemotherapy (AC) for older patients (OP) continues to be debated, with subgroup analyses of randomized trials not demonstrating a survival benefit from the addition of oxaliplatin to a fluoropyrimidine backbone.

Patients and Methods

We analyzed the multisite Australian ACCORD registry, which prospectively collects patient, tumor and treatment data along with long term clinical follow-up. We compared OP (≥70) with stage III CRC to younger patients ([YP] <70), including the proportion recommended AC and any reasons for not prescribing AC. AC administration, regimen choice, completion rates, and survival outcomes were also examined.

Results

One thousand five hundred twelve patients enrolled in the ACCORD registry from 2005 to 2018 were included. Median follow-up was 57.0 months. Compared to the 827 YP, the 685 OP were less likely to be offered AC (71.5% vs. 96.5%, P < .0001) and when offered, were more likely to decline treatment (15.1% vs. 2.8%, P < .0001). Ultimately, 60.0% of OP and 93.7% of YP received AC (P < .0001). OP were less likely to receive oxaliplatin (27.5% vs. 84.7%, P < .0001) and to complete AC (75.9% vs. 85.7%, P < .0001). The probability of remaining recurrence-free was significantly higher in OP who received AC compared to those not treated (HR 0.73, P = .04) but not significantly improved with the addition of oxaliplatin (HR 0.75, P = .18).

Conclusion

OP were less likely than YP to receive AC. Receipt of AC reduced recurrences in OP, supporting its use, although no significant benefit was observed from the addition of oxaliplatin.