Squamous cell carcinoma of the pharyngeal walls treated with radiotherapy

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.

Between May 1971 and December 1991, 74 patients with previously untreated squamous cell carcinoma of the pharyngeal walls (excluding nasopharynx, tonsil, and pyriform sinus) were treated with radical megavoltage irradiation with or without chemotherapy at Oregon Health Sciences University.

Two-year local control rates by stage were: T1: 100%, T2: 55%, T3: 31%, and T4: 29% . Twice-a-day irradiation improved local control rates as compared with once-a-day irradiation 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 improvement was seen in 2-year local control of all stages when chemotherapy was used in conjunction with once-a-day fractionation; however, six of eight patients (75%) treated with twice-a-day irradiation combined 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 patients treated with concurrent chemotherapy and b.i.d. irradiation (all with Stage T3 and T4 tumors) is a dramatic improvement over the 2-year local control rate of 30% (10 out of 33) for our entire group of patients 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: 1: 100%, II: 85%, III: 58%, IV: 40%. Overall survival rates by stage were: I: 75%, II: 67%, III: 33%, IV: 30%.

We advocate radical irradiation as the primary therapy for pharyngeal wall carcinomas with the use of twice-a-day fractionation for Stages T2-T4. Our preliminary results with concurrent chemotherapy and b.i.d. irradiation for advanced T3 and T4 tumors appear to be comparable to reported results with hyperfractionated radiation alone. The relative contribution of chemotherapy to b.i.d. irradiation cannot be determined from this small retrospective series; however, in view of the relatively poor results for patients with advanced stage disease, we feel this treatment combination deserves further investigation.