Ling-Long Tang1, Lei Chen1, Yan-Ping Mao1, Wen-Fei Li1, Ying Sun1, Li-Zhi Liu2, Ai-Hua Lin3, Hai-Qiang Mai4, Jian-Yong Shao5, Li Li2, Jun Ma6. 1. Department of Radiation oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China. 2. Imaging Diagnosis and Interventional Center, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China. 3. Department of Medical Statistics and Epidemiology, School of Public Health, Sun Yat-sen University, Guangzhou, People's Republic of China. 4. Department of Nasopharyngeal Carcinoma, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China. 5. Department of Molecular Diagnostics, State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China. 6. Department of Radiation oncology, Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, People's Republic of China. Electronic address: majun2@mail.sysu.edu.cn.
Abstract
BACKGROUND AND PURPOSE: This study investigated the contribution of intensity-modulated radiotherapy (IMRT) to improved treatment outcome in patients with nasopharyngeal carcinoma (NPC) and parapharyngeal space (PPS) extension. MATERIAL AND METHODS: A total of 1052 cases with PPS extension were retrospectively reviewed, including 512 (48.7%) patients treated with two-dimensional conventional radiotherapy (2D-CRT) and 540 (51.3%) patients treated with IMRT. RESULTS: Significant differences in local relapse-free survival (LRFS) and overall survival (OS) (P<0.001, P<0.001, respectively), but not distant metastasis-free survival (DMFS; P=0.383), were observed between the 2D-CRT and IMRT groups in univariate analysis. The radiotherapy technique was found to be an independent prognostic factor for death (HR=0.674, 95% CI: 0.537-0.846, P=0.001) and local recurrence (HR=0.486, 95% CI: 0.324-0.727, P<0.001), but not for DMFS. IMRT improved local control in patients with carotid space (CS) involvement compared to 2D-CRT (P<0.001). LRFS was significantly different between patients with and without CS extension in the 2D-CRT group (P<0.001), but not in the IMRT group (P=0.215). CONCLUSIONS: Compared to 2D-CRT, IMRT improved LRFS in patients with PPS extension, especially patients with CS extension, but did not improve DMFS. CS extension was not statistically prognostic for local control in NPC patients with PPS extension.
BACKGROUND AND PURPOSE: This study investigated the contribution of intensity-modulated radiotherapy (IMRT) to improved treatment outcome in patients with nasopharyngeal carcinoma (NPC) and parapharyngeal space (PPS) extension. MATERIAL AND METHODS: A total of 1052 cases with PPS extension were retrospectively reviewed, including 512 (48.7%) patients treated with two-dimensional conventional radiotherapy (2D-CRT) and 540 (51.3%) patients treated with IMRT. RESULTS: Significant differences in local relapse-free survival (LRFS) and overall survival (OS) (P<0.001, P<0.001, respectively), but not distant metastasis-free survival (DMFS; P=0.383), were observed between the 2D-CRT and IMRT groups in univariate analysis. The radiotherapy technique was found to be an independent prognostic factor for death (HR=0.674, 95% CI: 0.537-0.846, P=0.001) and local recurrence (HR=0.486, 95% CI: 0.324-0.727, P<0.001), but not for DMFS. IMRT improved local control in patients with carotid space (CS) involvement compared to 2D-CRT (P<0.001). LRFS was significantly different between patients with and without CS extension in the 2D-CRT group (P<0.001), but not in the IMRT group (P=0.215). CONCLUSIONS: Compared to 2D-CRT, IMRT improved LRFS in patients with PPS extension, especially patients with CS extension, but did not improve DMFS. CS extension was not statistically prognostic for local control in NPCpatients with PPS extension.