Clinical results of definitive intensity-modulated radiation therapy for oropharyngeal cancer: Retrospective analysis of treatment efficacy and safety

Abstract

Objective: To evaluate the clinical outcomes of intensity-modulated radiotherapy for patients with oropharyngeal carcinoma. Methods: Ninety-three oropharyngeal carcinoma patients histopathologically diagnosed with squamous cell carcinoma and treated with definitive intensity-modulated radiotherapy using helical tomotherapy between January 2006 and December 2013 were analyzed. Planning target volume primary and involved nodes was delivered 66-70 Gy at 2 Gy per fraction, while planning target volume prophylactic was delivered 54 Gy using the simultaneous integrated boost technique. Results: The median follow-up period among the surviving patients was 40 months (range, 13-96). There were 76 males and 17 females with a median age of 60 years (range, 34-80). The disease was Stage II in 13%, Stage III in 10% and Stage IV in 77% of patients. Ninety-two patients received chemotherapy (99%); 68 patients received induction chemotherapy (73%), while 21 received concurrent chemotherapy (23%). The 3-year overall survival, progression-free survival and locoregional control rates were 80, 68 and 79%, respectively. Multivariate analysis identified an advanced T-category (T3-4), having double cancer, and smoking habit as significantly unfavorable factors for overall survival, progression-free survival and both progression-free survival and locoregional control, respectively. Only two patients who achieved disease control required percutaneous endoscopic gastrostomy tubes in the last follow-up. The rate of Grade 2 xerostomia at 2 years was 23%. Conclusions: Intensity-modulated radiotherapy using helical tomotherapy for patients with oropharyngeal carcinoma provided not only sufficient efficacy, but also preserved parotid function.