Prospective Trial of Target Volume Delineation for Radiotherapy in Nasopharyngeal Carcinoma
ZHAO Chong, LU Li-xia, HAN Fei, et al. (State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-sen University, Guangzhou 510060, China)
[Purpose] To verify the rationality of target volume delineation and the clinical effect for nasopharyngeal carcinoma (NPC). [Methods] One hundred and fifty patients with NPC were enrolled in this study. Sixty-nine patients were treated by radiotherapy alone, and eighty-one patients received comprehensive radio-chemotherapy. The target volumes and the relevant planning target volumes (PTVs) were delineated. The step-by-step shrinked irradiation was carried out based on the different PTVs. Locoregional control and the relationship between the site of residual or recurrence and target volumes in radiography were analyzed after treatment. [Results] Single nasopharynx residual and single cervical residual was found in 2 and 3 cases respectively; 2 sites residual in 2 cases. Primary tumor regression rate and cervical metastasis regression rate were 97.3% and 96.7% respectively. Nasopharyngeal recurrence were found in 6 cases; cervical, 3 cases, with a median follow-up of 35.5 months.The 3-year local and regional control rate were 97.3% and 96.7%, respectively. Imaging analysis showed all nasopharyngeal residual and recurrence were inside the gross tumor volumes of the nasopharynx (GTVnx); cervical residual were inside the gross tumor volumes of the cervical lymph nodes (GTVnd). One cervical recurrent tumors was inside GTVnd; 2, inside CTV2. [Conclusions] According to the target volume delineation, satisfied locoregional control was achieved, and no recurrent tumor was observed outside or marginal to the target volumes after radiotherapy. The clinical result suggests that target volume delineation and the step-by-step shrinked irradiated technique are rational and feasible.