Efficacy and Toxicity of Triweekly Versus Weekly Cisplatin in Concurrent Chemoradiotherapy for Nasopharyngeal Carcinoma.

This retrospective study compared the efficacy and toxicity of concurrent triweekly versus weekly cisplatin in patients with previously untreated, biopsy-proven NPC who received definitive CRT followed by adjuvant chemotherapy. Patients with distant metastasis, Karnofsky Performance Status < 80, induction chemotherapy, or no adjuvant therapy were excluded. Medical records of 205 patients treated between June 2000 and June 2023 were reviewed. Patients received triweekly cisplatin (100 mg/m2 every 3 weeks [administered as 50 mg/m2 on days 1 and 2 every 21 days]) or weekly cisplatin (40 mg/m2), with radiotherapy to 70 Gy/35 fractions or 69.96 Gy/33 fractions. Treatment outcomes were analyzed using the Kaplan-Meier method and Cox proportional hazards model, while toxicity profiles were compared using the chi-square test. After a median follow-up of 76 months, the 10-year overall survival rate was 76.5%. The cumulative cisplatin dose was higher in the triweekly group (263.9 ± 50.1 vs. 247.8 ± 35.4 mg/m2, p = 0.0107), while the weekly group included more patients older than 50 years (63.2% vs. 46.6%, p = 0.0338). No significant differences were observed between the triweekly and weekly groups in overall survival (p = 0.9096) and progression-free survival (p = 0.9186). The weekly cisplatin group exhibited a higher incidence of Grade 1-2 hypomagnesemia (p = 0.0415). Other acute toxicities, including gastrointestinal, renal, hematologic, otologic, neurologic, and electrolyte toxicities, as well as 1-year post-treatment kidney injury, hearing impairment, tinnitus, and peripheral neuropathy, were comparable between groups. These findings demonstrate similar survival outcomes and toxicity profiles between concurrent triweekly and weekly cisplatin regimens in NPC treated with curative CRT followed by adjuvant chemotherapy.