Response of chemoradiation therapy after induction chemotherapy failure in locally advanced head and neck squamous cell carcinoma (LA-HNSCC).

Abstract

5552 Background: Although induction chemotherapy (IC) for LA-HNSCC has shown high response rates, some patients do not respond to IC. Surgery has been the usual choice for the non-responding patients, but practically, not all of these patients are eligible for operation. The purpose of this study was to evaluate the efficacy of definitive radiation therapy (RT) for the HNSCC patients who failed IC. Methods: We have retrospectively analyzed the outcome of patients with LA-HNSCC who were initially treated with IC at Seoul National University Hospital between Jan. 2006 and Dec. 2010. Chemotherapeutic regimens used were 5-FU/cisplatin, docetaxel/5-FU/cisplatin, and docetaxel/cisplatin with or without cetuximab. After IC, patients were treated with RT, concurrent chemoradiation (CCRT), or surgery, either alone or with postoperative RT. Treatment modality was chosen on multi-disciplinary basis of our institution. Response was evaluated using RECIST criteria. Results: A total of 225 LA-HNSCC patients treated with IC were analyzed. Median age was 54 (range 24-77). Primary tumor locations were oral cavity (39.5%), nasal cavity/paranasal sinus (13.1%), oropharynx (13.1%), nasopharynx (13.1%), larynx (7.9%) and hypopharynx (13.1%). Among the 225 patients, 38 (16.9%) patients did not respond to IC [stable diseases (SD) = 23 (10.2%), progressive disease (PD) = 15 (6.7%)], and their median overall survival was 14.5 months. Among the 38 non-responders, 14 (36.8%) patients were undertaken surgery and 22 (57.8%) unresectable or inoperable patients were treated with either definitive RT or CCRT. Responses to subsequent definitive RT or CCRT for 20 evaluable patients were as follows: complete response = 6 (30.0%), partial response = 7 (35.0%), SD = 3 (15.0%), PD = 4 (20.0%) Overall response rate to definitive RT or CCRT in non-responder to IC was 65.0% (95%CI: 44.1%- 85.9%). Nine out of 15 patients who showed PD to IC received definitive RT or CCRT and interestingly, 3 (33.3%) patients responded to definitive RT or CCRT. Conclusions: A significant portion of HNSCC patients who failed to IC can benefit from subsequent definitive RT or CCRT. Further prospective study is warranted.