Comparison of toxicities and treatment outcome of weekly and triweekly cisplatin concurrent with intensity-modulated radiotherapy for locally advanced nasopharyngeal carcinoma

Objective To evaluate the rates of hematologic and mucosal toxicities and treatment outcome of a weekly cisplatin (QW) and triweekly cisplatin (Q3W) regimens concurrent with intensity-modulated radiotherapy (IMRT) for local regionally advanced nasopharyngeal carcinoma (NPC). Methods A total of 148 patients with biopsy-proven NPC staged at Ⅲ to IVB were retrospectively enrolled from October 2009 to December 2013 in this study. Among all patients, 75 and 73 received QW and Q3W cisplatin chemotherapy regimens concurrent with IMRT, respectively. All patients received neoadjuvant chemotherapy. The χ2-test was used to compare clinical characteristics of the patients and hematologic and mucosal toxicities. Tumor response and survival rates were estimated through the Kaplan-Meier method with log-rank test. Results The mean total cycles of the cisplatin regimen was 3.64 in the QW group with 15 patients(20%) reaching five cycles and 1.86 in the Q3W group with 86% reaching two cycles. Grades 1, 2 leucopenia were 31% vs. 51% and 35% vs. 19%, respectively, in the QW and Q3W groups. The two groups showed significant differences in Grades 1 and 2 leucopenia (χ2= 6.150, 4.500, both P<0.05) but not for other hematological toxicities and mucositis (χ2= 0.137, P=0.934). The complete remission rates at 6 months after radiotherapy for the QW and QW3 groups were 98.7% and 98.6%, respectively. The 5-year estimated overall survival, disease-free survival, local recurrence-free survival, regional recurrence-free survival, and distant metastasis-free survival rates of the QW and Q3W groups were 77.84% vs. 79.97% (χ2=3.78, P=0.059), 67.96% vs. 69.10% ( χ2=1.25, P=0.27), 88.76% vs. 86.96% (χ2=0.43, P=0.56), 91.49% vs. 90.84% (χ2=0.18, P=0.67), and 77.86% vs. 78.90% (χ2=0.31, P=0.56), respectively, and were not significantly different between the two groups. Conclusions Hematological toxicities associated with the QW3 regimen concurrent with IMRT for locally advanced NPC were milder than those associated with the QW weekly regimen. Mucositis and treatment outcome did not significantly differ between the two groups. Patients showed better compliance with the Q3W regimen than with the QW regimen. Key words: Nasopharyngeal neoplasms; Radiotherapy, intensity modulated; Drug cherapy; Cisplatin