The evaluation of amifostine for mucosal protection in patients with advanced loco-regional squamous cell carcinomas of the head and neck (SCCHN) treated with concurrent weekly carboplatin, paclitaxel, and daily radiotherapy (RT)

Abstract

Concurrent chemotherapy and radiation has improved the outcome for patients presenting with locally advanced squamous cell carcinomas of the head and neck (SCCHN). These improvements have come at a cost of increased treatment-related toxicities. We previously reported the results of a phase II trial examining the role of concurrent carboplatin, paclitaxel, and daily radiotherapy (RT) in SCCHN. In an attempt to decrease these side effects, we conducted a prospective phase II trial evaluating the role of amifostine (Ethyol, MedImmune Oncology, Inc, Gaithersburg, MD) in patients treated with this concurrent chemoRT scheme. From April 2002 to September 2004, 19 patients with stage III-IV SCCHN were enrolled on a prospective phase II trial. Treatment consisted of daily RT delivered to 70.2 Gy (1.8 Gy/fx) with amifostine 500 mg IV (<1 hour before RT), and concurrent weekly carboplatin (100 mg/m2) and paclitaxel (40 mg/m2). Median age was 58.5 years (range, 48 to 70 years); male to female ratio was, 83%:17%; Caucasian versus other was, 61%/39%. Tumor characteristics based on histology were: primary cancers of the oropharynx (55.6%); supraglottic larynx (16.7%); hypopharynx (16.7%); oral cavity (5.6%); and unknown primaries (5.6%). All patients presented with locally advanced, unresectable disease T4 (50%), T3 (27.8%), and advanced nodal disease (N2b-N3) (78%). Toxicities were measured weekly during treatment and at each follow-up visit. Disease response to therapy was determined 2 months after completion of therapy. Seventeen patients are evaluable for response and survival at 2 months following completion of RT. Eighty-four percent completed the prescribed radiation treatment, and 84% of patients received more than six cycles of chemotherapy. The median number of missed chemotherapy cycles was 1.5 (range, 0 to 5 cycles). Fifty-six percent of patients received more than 90% of prescribed amifostine doses, with chemoRT-related toxicity being the most common reason for withholding the dose (77%). Median doses of missed amifostine were three (range, 0 to 30 doses). Grade 3 toxicities associated with therapy were: mucositis and dysphagia (40% of patients each), dehydration (27%), xerostomia (20%), and dermatitis (20%); 53% of patients experienced grade 3 leukopenia, while grade 3/4 neutropenia developed in 20%/13%. No grade 4/5 nonhematologic toxicities were encountered. Forty percent of patients completed RT without unscheduled treatment breaks secondary to treatment-related toxicity. Median treatment-break time was 5 days (range, 0 to 20 days). Clinical complete response at both the primary site of disease and neck was achieved in 75% of patients 2 months following completion of RT. Weekly carboplatin and paclitaxel administered concurrently with definitive RT and daily amifostine is well tolerated, with over 85% of patients completing therapy with acceptable toxicity. The addition of amifostine appears to decrease treatment-related toxicity without impacting efficacy.