SQUAMOUS-CELL CARCINOMA OF THE PHARYNGEAL WALLS TREATED WITH RADIOTHERAPY

Purpose: To assess the impact of fractionation schedule, chemotherapy, and tumor location on local control and survival in patients treated with definitive irradiation for carcinoma of the pharyngeal walls. Met hods and Materials: Between May 1971 and December 1991, 74 patients wi th previously untreated squamous cell carcinoma of the pharyngeal wall s (excluding nasopharynx, tonsil, and pyriform sinus) were treated wit h radical megavoltage irradiation with or without chemotherapy at Oreg on Health Sciences University. Results: Two-year local control rates b y stage were: T1: 100%, T2: 55%, T3: 31%, and T4: 29%. Twice-a-day irr adiation improved local control rates as compared with once-a-day irra diation for patients with Stage T3 lesions, with 5 out of 7 (71.4%) vs . 4 out of 19 (21%) patients controlled at 2 years (p = 0.015). No imp rovement was seen in 2-year local control of all stages when chemother apy was used in conjunction with once-a-day fractionation; however, si x of eight patients (75%) treated with twice-a-day irradiation combine d with either induction or concurrent chemotherapy had local control. The 2-year local control rate of 100% (6 out of 6) for the group of pa tients treated with concurrent chemotherapy and b.i.d. irradiation (al l with Stage T3 and T4 tumors) is a dramatic improvement over the 2-ye ar local control rate of 30% (10 out of 33) for our entire group of pa tients with Stage T3 and T4 tumors. Local control rates did not differ by tumor location on the pharyngeal walls. Adjusted disease-specific survival rates by stage were: I: 100%, II: 85%, III: 58%, IV: 40%. Ove rall survival rates by stage were: I: 75%, II: 67%, III: 33%, IV: 30%. Conclusion: We advocate radical irradiation as the primary therapy fo r pharyngeal wall carcinomas with the use of twice-a-day fractionation for Stages T2-T4. Our preliminary results with concurrent chemotherap y and b.i.d. irradiation for advanced T3 and T4 tumors appear to be co mparable to reported results with hyperfractionated radiation alone. T he relative contribution of chemotherapy to b.i.d. irradiation cannot be determined from this small retrospective series; however, in view o f the relatively poor results for patients with advanced stage disease , we feel this treatment combination deserves further investigation.