Postoperative chemotherapy relative dose intensity and overall survival in patients with colon cancer

Quantifying the association of chemotherapy relative dose intensity (RDI) with overall survival may enable supportive care interventions that improve chemotherapy RDI to estimate their magnitude of potential clinical benefit.

This cohort study included 533 patients with stage II-III colon cancer who initiated a planned regimen of 12 cycles of 5-fluorouracil, leucovorin, and oxaliplatin (FOLFOX) chemotherapy. The primary exposure was chemotherapy RDI. The primary outcome was overall survival. Restricted cubic splines estimated hazard ratios (HR).

Chemotherapy regimen RDI was associated with overall survival in an L-shaped pattern (linear P = 0.006; nonlinear P = 0.057); the risk of death was flat above 85% but increased linearly below 85%. For example, a decrease in RDI from 85 to 75% was associated with an increased risk of death [HR: 1.20 (95% CI: 1.08, 1.52)], whereas an increase in RDI from 85 to 95% was not associated with the risk of death [HR: 1.06 (95% CI: 0.82, 1.38)].

If chemotherapy RDI is considered a potential surrogate of overall survival, supportive care interventions that improve chemotherapy RDI might confer a potential clinical benefit in this population.