Association of baseline patient characteristics with adjuvant chemotherapy toxicities in stage III colorectal cancer patients

Toxicities can affect cancer patients’ quality of life resulting in poor adherence to adjuvant chemotherapy (AC). While previous studies have explored the prevalence of toxicities following AC, few have examined the associations of baseline characteristics, such as age, sex, and performance status, with toxicity outcomes. In this study, we reviewed a cohort of 371 colorectal cancer patients treated with adjuvant monotherapy (capecitabine ) or combination therapy (FOLFOX or CAPOX) within 12 weeks of curative resection, and determined the associations between baseline characteristics and toxicity outcomes. Median age was 65 years, 52% were men, and 41% received monotherapy. A number of toxicities appeared to decrease with successive AC cycles. For monotherapy, univariate analyses found that age, sex, performance status, and pre-treatment anemia were associated with hematological toxicities whereas tumor location was associated with gastrointestinal (GI) toxicities (all P < 0.05). On multivariate analyses, hematological toxicities were predicted by advanced age (≥ 70) (OR 3.30; 95% CI 1.17–9.37; P = 0.025) and pre-treatment anemia (OR 23.18; 95% CI 6.36–84.48; P < 0.001), while GI toxicities were less likely to occur among tumors at or distal to the splenic flexure (OR 0.38; 95% CI 0.15–0.99; P = 0.047). For combination therapy, sex and pre-treatment anemia were associated with hematological toxicities (all P < 0.05), but only female sex was predictive on multivariate analyses (OR 5.13; 95% CI 2.08–12.68; P < 0.001). In conclusion, few baseline characteristics were associated with treatment toxicities. These findings may better inform discussions with patients and caregivers during AC decision-making and underscore to clinicians the need for close monitoring of patients during treatment.