Excellent Locoregional Control and Mild Late Toxicity after Reducing Target Volumes and Radiation Doses in Locoregionally Advanced Nasopharyngeal Carcinoma Patients Treated with Induction Chemotherapy (IC) Followed by Concurrent Chemoradiotherapy: Ten-Year Results of a Phase II Study
Menée en Chine auprès de 112 patients atteints d'un carcinome rhinopharyngé de stade locorégionalement avancé et traité par chimiothérapie d'induction puis chimioradiothérapie concomitante (durée médiane de suivi : 126 mois), cette étude met en évidence un contrôle locorégional élevé et une toxicité à long terme de faible grade après réduction des volumes cibles et des doses de rayonnements de la radiothérapie
Purpose : To evaluate the long-term locoregional control, failure patterns and late toxicity after reducing the target volume and radiation dose in locoregionally advanced nasopharyngeal carcinoma (LANPC) patients treated with induction chemotherapy (IC) plus concurrent chemoradiotherapy (CCRT). Methods and Materials : Previously untreated LANPC patients were recruited into this prospective study. All patients received two cycles of IC followed by CCRT. The gross tumor volumes of the nasopharynx (GTVnx) and the neck lymph nodes (GTVnd) were delineated according to the post-IC tumor extension and received full therapeutic doses (68 Gy and 62-66 Gy, respectively). The primary tumor shrinkage after IC was included in the high-risk clinical target volume (CTV1) with a reduced dose of 60Gy. The locoregional recurrence-free (LRRFS), distant metastasis-free (DMFS), and overall survival (OS) were calculated using the Kaplan-Meier method. The location and extent of locoregional recurrences were transferred to pretreatment planning computer tomography for dosimetry analysis. Results : There were 112 patients enrolled in this study. The average mean dose of post-GTVnx, post-GTVnd (left), post-GTVnd (right), post-CTV1 and post-CTV2 was 75.24 Gy, 68.97 Gy, 69.16 Gy, 70.49 Gy and 63.37 Gy, respectively. With a median follow-up of 125.95 months, the 10-year LRRFS, DMFS, and OS were 89.0%, 83.3%, and 75.9%, respectively. There were 8 local recurrences and 6 regional recurrences in 12 patients. All 8 of the local recurrences were in-field; among the 6 regional recurrences, 4 were in-field, 1 was marginal and 1 was out-field. The most common late toxicities were grade 1-2 subcutaneous fibrosis, hearing loss and xerostomia. No grade 4 late toxicities were observed. Conclusions : Reduction of the target volumes according to the post-IC tumor extension and radiation dose to the post-IC tumor shrinkage could yield excellent long-term locoregional control with limited marginal and out-field recurrences and mild late toxicities.
https://www.redjournal.org/article/S0360-3016(19)30570-X/fulltext