Prognostic significance of the total dose of cisplatin administered during concurrent chemoradiotherapy in patients with locoregionally advanced nasopharyngeal carcinoma

Background and purposeConcurrent chemoradiotherapy (CRT) confers survival benefit over radiotherapy (RT) alone in the treatment of locoregionally advanced nasopharyngeal carcinoma (NPC). This study explored the prognostic significance of the total dose of cisplatin delivered during CRT.Materials and methodsA retrospective analysis was performed in patients with stage II to IVB NPC (AJCC 6th edition) who participated in 3 prospective studies. All patients received cisplatin at a fixed dose of 40 mg/m2/week during a 6–7-weeks course of CRT. Chi-square test was used in the univariate analysis. Relationship between prognostic factors, the total dose of cisplatin administered and time-to-event endpoints were analyzed with the Cox Hazards model.ResultsTwo hundred and forty-one patients were identified with the following stage distribution: Stage II = 13.7%, III = 45.2%, IV = 41.1%. The median total number of cycles of cisplatin administered per patient was 5 cycles (range 1–8 cycles). At a median follow-up of 56.5 months (range 4.2–200.2 months), 93 patients (38.6%) had relapsed and 85 patients (35.2%) died. For all patients, the total number of cycles of cisplatin delivered was significantly associated with survival in the univariate but not the multivariate analysis. In a sub-group analysis of 142 patients with stage II and III NPC, patients who received more than 5 cycles of cisplatin had significantly better overall survival than those who did not (hazard ratio 0.44; 95% confidence interval, 0.23–0.85; p = 0.02).ConclusionNumber of cycles of cisplatin delivered is an independent prognostic factor in patients with stage II–III NPC undergoing CRT with weekly cisplatin.