Background: Depression and anxiety are prevalent in older adults with cancer but are often undertreated. Older adults are also at increased risk of chemotherapy toxicity (CT). This study evaluated the impact of depression and anxiety symptoms on severe CT risk in older adults with cancer.

Methods: This is a secondary analysis of a randomized trial (2:1) evaluating geriatric assessment-driven intervention (GAIN) versus standard of care (SOC) to reduce grade 3+ CT in older adults with cancer. Mental health was assessed via the Mental Health Inventory 13. CT was graded by National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0.

Results: A total of 605 patients enrolled (402 GAIN; 203 SOC). Overall, 35% were depressed and 47% were anxious. Patients with depression had increased CT in the SOC arm (70.7% vs. 54.3%; p = .02) but not in the GAIN arm (54.3% vs. 48.5%; p = .27). CT was more likely in SOC patients with depression (odds ratio [OR], 2.03; 95% CI, 1.10-3.72). This association persisted after adjusting for Cancer and Aging Research Group toxicity score (OR, 1.98; 95% CI, 1.07-3.65) and for demographic, disease, and treatment factors (OR, 2.00; 95% CI, 1.03-3.85). Depression and CT were not associated in the GAIN arm (OR, 1.26; 95% CI, 0.84-1.91). Anxiety and CT were not associated in either arm.

Conclusions: Elevated depression symptoms are associated with increased risk of severe CT in older adults with cancer, which was mitigated with GAIN. This suggests that treating depression symptoms may lower toxicity risk. Future studies are needed to confirm and investigate the impact of depression-specific interventions on outcomes.