The association of oxaliplatin-induced peripheral neuropathy and falls with intercycle delays and early discontinuation of chemotherapy in older colorectal cancer patients.

Purpose: Oxaliplatin chemotherapy improves survival in patients with colorectal cancer, but a common dose-limiting toxicity is oxaliplatin-induced peripheral neuropathy (OIPN). The purpose of this study was to assess the association between OIPN and falls with intercycle delays and early discontinuation of oxaliplatin chemotherapy.

Methods: Colorectal cancer patients in this study were obtained from the Surveillance, Epidemiology, and End Results database combined with Medicare claims data (SEER-Medicare). All patients were ≥ 66 years of age at diagnosis. OIPN and falls were considered time-dependent exposures and were identified by diagnosis codes. Intercycle chemotherapy delay was defined as receipt of chemotherapy ≥ 7 days after the planned chemotherapy date. Early discontinuation was determined according to the chemotherapeutic regimen (infusional 5-FU < 6 cycles, oral capecitabine < 4 cycles). Poisson regression with generalized estimating equations and 95% confidence intervals was used to obtain adjusted incidence rate ratios (IrR) and rate differences (IrD) for intercycle delays and risk ratios (RR) and risk differences (RD) for early discontinuation.

Results: A total of 3802 patients were available for analysis. Intercycle oxaliplatin delay occurred in 57.7% of subjects (n = 2194). OIPN (IrR = 1.87: 95% CI, 1.67-2.10; IrD = 2.09 delays/81 person-days: 95% CI, 1.48-2.69) and falls (IrR = 2.62: 95% CI, 2.06-3.34; IrD = 3.30 delays/81 person-days: 95% CI, 1.96-4.64) were associated with increased rates of delay. Early discontinuation of chemotherapy occurred in 22.1% of patients (n = 841). OIPN (RR = 2.51: 95% CI, 1.78-3.55; RD = 7.2%; 95% CI, 3.0-11.4%) and falls (RR = 2.19; 95% CI, 1.24-3.85) were also associated with increased risks of early discontinuation.

Conclusion: Patients who experience intercycle delays and early discontinuation of scheduled chemotherapy treatment may experience poorer cancer-related outcomes. Therapeutics to prevent and treat OIPN and fall prevention strategies are needed to decrease the likelihood of chemotherapy treatment disruptions in older colorectal cancer patients.