Feasibility of 6 months of maintenance cetuximab after adjuvant concurrent chemoradiation plus cetuximab in squamous cell carcinoma of the head and neck (HNC).

Abstract

e16033 Background: The prognosis for HNC patients (pts) after surgical treatment and adjuvant chemoradiation (CRT) is unsatisfactory in case of close resection margin <5 mm (CM) or extra capsular extent at the lymph nodes (ECE). Therefore we conducted a multicenter phase II study to investigate the toxicity and efficacy of adjuvant radiotherapy (RT) in combination with concurrent cisplatin, 5- fluorouracil (5FU), and cetuximab (CTX) followed by maintenance therapy with CTX for 6 months. Here, we present the preliminary results on feasibility and toxicity. Methods: HNC pts after primary surgery were eligible for the study, if a CM or ECE was detected. Cisplatin [20 mg/m2 d1-5 and d29-33] and 5-FU (CI 600 mg/m2 d1-d5 + d29-33) were given concurrently to postoperative RT using an integrated boost IMRT-technique (1.8/2.0/2.2Gy QD) to a total dose of 61.6 Gy. CTX started 7 days prior CRT with a loading dose of 400 mg/m2 followed by weekly CTX (250 mg/m2) during CRT. Maintenance CTX started after completion of CRT plus CTX with 500 mg/m² every 2 weeks over a 6-month period. Results: 55 of 80 planned pts (46 male, 9 female, mean age 55.6, range 29-70 years) have finished CRT, 50 are evaluable for toxicity. Concurrent CRT plus CTX was associated with grade 3-4 (CTC 3.0) mucositis, radiation dermatitis, and skin reaction outside the radiation portals in 46%, 28%, and 14% of pts, respectively. One toxic death occurred (peritonitis at day 57). CTX was terminated in 10% of all pts (allergic reactions) after the first application. In 22% of all pts CTX was discontinued during the last 2 weeks or at the end of CRT. Of those pts embarking on maintenance therapy, 80% were still on CTX after 3 and 63% after 5 months. 48% completed 6 months maintenance therapy. Conclusions: Adjuvant CRT in combination with CTX followed by maintenance CTX is feasible with toxicity in the expected range. Compliance to maintenance CTX was satisfactory during the first 3-5 months.