Adjuvant chemotherapy less effective in elderly CRC patients

A subgroup analysis of the TOSCA trial showed elderly colorectal cancer (CRC) patients (≥70 years) to benefit less from adjuvant chemotherapy compared with younger patients.

TOSCA is 1 of the 6 randomised, phase 3 clinical trials of the IDEA consortium, demonstrating non-inferiority of 3 months adjuvant chemotherapy as compared with 6 months chemotherapy in patients with stage III colon cancer [1]. However, a reduced benefit of adjuvant chemotherapy for patients over the age of 70 years is suggested.

Therefore, a subgroup analysis of TOSCA was performed [2]. Primary endpoint of this subgroup analysis was relapse-free interval (RFI), defined as time from randomisation to relapse or last disease evaluation. In TOSCA, 2,360 patients with stage III disease were enrolled: 1,667 aged <70 (‘younger patients’) and 693 aged ≥70 (‘elderly patients’). The elderly patients had an ECOG performance status more often equal to 1 compared with the younger patients (10% vs 3%), more T3/T4 tumours (91% vs 84%), and more tumours located on the right (49% vs 36%). More elderly patients had dose reductions (47% vs 41%) and prematurely interrupted the treatment (26% vs 19%).

In elderly patients, a higher proportion of recurrences was observed (24% vs 20%; P=0.033). However, the multivariable analysis of the RFI, corrected for sex, ECOG performance status, tumour site, stage, and grade, treatment, treatment duration, and dose reduction, did not indicate a statistically significant effect of age (HR 1.19; P=0.082). As such, different prognostic factors and possibly a reduced compliance may account for the observed difference in benefit of adjuvant chemotherapy between elderly and younger patients.

1. Grothey A, N Engl J Med 2018;378:1177-1188.
2. Rosati G, et al. Oxaliplatin plus fluoropyrimidines as adjuvant therapy for colon cancer in elderly patients: A subgroup analysis from TOSCA trial. ESMO 2020 Virtual Meeting, abstract 399O.

Posted on 25 November, 202028 March, 2024