PHARYNGEAL WALL CARCINOMA TREATED WITH RADIOTHERAPY - IMPACT OF TREATMENT TECHNIQUE AND FRACTIONATION

Purpose: To determine whether a modification in treatment technique and the routine use of twice-daily fractionation have influenced the likelihood of local control in carcinomas of the hypopharyngeal and/or oropharyngeal wall. Methods and Materials: Between October 1964 and July 1990, 99 patients with invasive, previously untreated T1-T4 squamous cell carcinoma of the pharyngeal wall were treated with continuous-course, external-beam radiotherapy with curative intent at the University of Florida. All patients had a minimum 2-year follow-up. Results: The 2-year local control rates for patients treated with once-daily vs. twice-daily fractionation were T1, 100% each; T2, 67% vs. 92%; T3, 43% vs. 80%; and T4, 17% vs. 50%. The 2-year local control rates for patients treated with our former technique (posterior border placed at middle of the vertebral body when the portals were reduced off the spinal cord) vs. our current, modified technique (posterior border placed at posterior edge of the vertebral body) were T1, 100% each; T2, 57% vs. 100%; T3, 46% vs. 73%; and T4, 29% vs. 75%. The parameters of T stage, fractionation schedule, primary site, (oropharynx vs. hypopharynx) treatment technique, and lateral vs. posterior pharyngeal wall location were evaluated in a multivariate analysis for the end point of local control. T stage (p = .003), fractionation schedule (p = .001), and primary site (p = .028) were of independent prognostic Conclusion: Twice-daily fractionation was the most important treatment-related variable in this patient population.