Intravenous vitamin C did not reduce gastrointestinal toxicities but attenuated platelet decline in nasopharyngeal carcinoma patients.

This study was a randomized, double-blind, placebo-controlled trial conducted in Thailand, involving patients with nasopharyngeal carcinoma undergoing concurrent chemoradiotherapy. The intervention was 2 g of intravenous vitamin C administered prior to chemotherapy, compared with a placebo. The primary outcome was not reported, but secondary outcomes included gastrointestinal adverse effects (nausea, anorexia, mucositis, diarrhea, and dysphagia) and platelet counts. For gastrointestinal adverse effects, the incidence did not differ significantly between the vitamin C and placebo groups. In contrast, platelet counts showed a significantly attenuated decline in the vitamin C group compared with placebo, though specific effect sizes, absolute numbers, and p-values or confidence intervals were not provided. Safety and tolerability data, including adverse events, serious adverse events, and discontinuations, were not reported in the input. Key limitations include that the effects of vitamin C in nasopharyngeal carcinoma remain unclear, and the study did not report sample size, follow-up duration, or detailed statistical measures. In practice, the observed platelet preservation suggests a potential supportive effect that warrants further investigation, but clinicians should note that intravenous vitamin C did not reduce gastrointestinal toxicities, and broader efficacy and safety profiles are uncertain.