Prophylactic irradiation of cervical lymph nodes for Stage-N0 nasopharyngeal carcinoma

Fang-Yun Xie , Miao Peng, Wei-Han Hu, Fei Han, Xin Wang , Hui-Min Xu

State Key Laboratory of Oncology in South China, Guangzhou, 510060, Guangdong, P. R. China. xiefangy@mail.sysu.edu.cn

[Abstract] Background and Objective: It is controversial for the irradiation level and dose of the regional prevention for nasopharyngeal cancer (NPC) with one or both cervical lymph node-negative neck. This study was to analyze the prophylactic irradiation of cervical lymph nodes for Stage-N0 NPC patients. Methods: From January 2002 to December 2004, 205 patients with NPC, whose negative cervical lymph nodes were diagnosed by imageology, were analyzed retrospectively. CT scan or MRI before treatment was performed to every patients. Six to 8 MV photons and facio-cervical portals were used in radiotherapy. Sixty to 80 Gy had been given to nasopharynx, and 46 to 64 Gy to clinically negative lymph nodes. Consecutive radiotherapy was performed employing conventional fraction of 2 Gy per fraction, once a day and total 5 fractions per week. Chemotherapy was administered to 60 patients. Median follow-up was 44 months. The accumulated survival was calculated according to the Kaplan-Meier method. Log-rank test was used to compare the survival difference. Cox proportional hazards model was used for multivariate analysis. A total of 205 patients with Stage-N0 NPC were divided into the upper-neck group and whole-neck group. Results: The 3-year overall survival rate (OS) was 92.9% and the 3-year disease-free survival rate (DFS) was 91.9% in 205 patients with Stage-N0 NPC. There were 88 patients who had received prophylactic irradiation involved in the upper neck, while the other 117 in the whole neck. The rate of regional failure in the upper-neck group and in the whole-neck group were 2.27% and 0%(P>0.05), respectively. The rates of regional failure in Stages T1, T2, T3, and T4 patients were 0%, 3.08%, 0%, and 0%(P>0.05), respectively. The rates of regional failure in the patients without and with local failure were 1.03% and 0% (P>0.05). The 1-year and 3-year OS of upper-neck group were 97.7% and 94.2%, and those of whole-neck group were 97.4% and 91.9% (P=0.950). The 1-year and 3-year DFS of upper-neck group were 96.6% and 92.9%, and those of whole-neck group were 95.6% and 90.9% (P=0.730). Multivariate analysis showed that gender (P=0.039) and T stage (P=0.004) were independent prognosis factors of N0-NPC patients. Conclusions: Prophylactic irradiation to the upper neck doesn’t influence the regional failure or long-term survival in Stage-N0 NPC patients. Prophylactic irradiation to the upper neck (level II,III,VA) is recommendable for Stage-N0 NPC patients. The parapharyngeal space involvement, T stage, and the rates of local failure don’t influence the regional failure in Stage-N0 NPC patients. Gender and T stage were independent prognosis factors of Stage-N0 NPC patients.

Chinese Journal of Cancer 2010, Volume: 29, Issue 1, Page: 100-

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