Long-Term Outcomes of Reduced High-Risk Clinical Target Volume Margin for Intensity-Modulated Radiotherapy in Locally Advanced Head and Neck Cancers

Long-term outcomes of intensity modulated radiotherapy with reduced high-risk clinical target volume (HRCTV) margin for radical chemoradiation of locally advanced head and neck cancers (LAHNSCC). The present retrospective study involved 83 LAHNSCC patients treated with chemoradiation. HRCTV was created with uniform margins of 5 mm around the primary tumor- gross tumor volume (GTV), and the nodal tumor GTV, edited at bone and air interface. The first echelon nodal station in N0 neck and that harboring disease in N+ neck was taken as intermediate-risk clinical target volume (IR-CTV). The remaining nodal stations were taken as low-risk CTV. High-, intermediate-, and low-risk regions were prescribed 70, 63, and 56 Gy, respectively, in 35 fractions, five to six fractions per week over six to seven weeks. 63 patients received five fractions and 20 patients received six fractions per week. Acute toxicities were assessed using CTCAE version 4.0 and the survival analysis was performed via Kaplan Meier method. Acute toxicities were grade 1 dermatitis in 77%, grade 3 mucositis in 35%, and xerostomia was predominantly grade 1 in 68.6%. Moreover, 10% required the placement of nasogastric tube during radiation therapy due to grade 3 dysphagia. Complete clinical and radiological response (CR) of respectively 89.1% and 85.5% was observed in primary and nodal disease at the end of the treatment and 100% and 94% at three months, respectively, after chemo radiation therapy. At a median follow-up of 48.1 months, the five-year overall survival was 63.2%. Reduced HRCTV margin of 5 mm was found to be efficient and had good compliance with tolerable acute toxicities, reduced overall treatment time, and reas onable long-term outcomes.