Dose-capping chemoradiotherapy tied to higher recurrence in rectal cancer

The risk of disease recurrence is increased among rectal cancer patients treated with dose-capped chemoradiotherapy (CRT), reveals a study. In addition, excessive toxicity has occurred among those dosed by actual body surface area (BSA) compared to patients in the dose-capped group.

A team of investigators assessed the effect of chemotherapy dose-capping on disease recurrence, toxicity, and survival of 601 rectal cancer patients treated with CRT. Dose-capped patients were defined as having a BSA ≥2.0 m² and who received <95 percent full weight-based chemotherapy dose.

Factors associated with the outcome variables (capped vs uncapped) were analysed through binary logistic regression, while Kaplan-Meier estimation was conducted to assess significant predictors of survival. Median follow-up time was 7.54 years.

Dose-capped patients had a significantly higher rate of disease recurrence than those without dose-capping (35 percent vs 24 percent; p=0.016). Compared to uncapped patients, dose-capped ones had 64-percent greater likelihood of recurrence (odds ratio, 1.64, 95 percent confidence interval, 1.10–2.43)

In general, dose-capped patients were less likely to experience significant toxicity that warranted dose reduction or treatment break compared with their uncapped counterparts (15 percent vs 28 percent; p=0.008).

Significant differences were noted in progression-free survival between the capped and uncapped groups (77 percent vs 85 percent, respectively; p=0.017). Moreover, the 5-year overall survival rate was 75.0 percent in the capped group and 80 percent in the uncapped group (p=0.149).

“We recommend that chemotherapy dose-capping based on BSA should not be practiced in rectal cancer patients undergoing CRT,” the investigators said.