A Feasibility Study of Concomitant Boost Radiotherapy for Patients with Cancer of the Supraglottic Larynx

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Abstract
Between February 1988 and December 1989, 65 patients with supraglottic cancer completed a course of concomitant boost radiotherapy. Cases with N3 disease, a Karnovsky performance score less than 70, age above 70 years, or a second primary cancer were not eligible for the study. Distribution of the patients was: Stage T1-T2 30%, T3-T4 70%, N0 68%, N+ 32%. The total dose ranged from 60 Gy to 76 Gy (median 66 Gy); overall treatment time ranged from 36 to 56 days with a median of 42 days. The daily dose during the first 4 weeks was 1.8 Gy, and during the last 2 weeks it was 1.6 Gy b.i.d. with a 4- or (after September 1988) 6-h interval. The clinical impression was that the early mucosal reactions were acceptable but more severe than after conventional treatment, with confluent membranous mucosal reaction being observed in 54% of the patients. Also, this reaction was significantly more frequent in patients treated with a 4-h interval (68%) than with a 6-h interval (41%) between the daily fractions. To relieve severe dysphagia, narcotics were required in 22% of the patients. The follow-up time ranged from 22 to 50 months, median 34 months. Treatment-requiring late complications were observed in 8 patients, and the 3-year actuarial risk was 17% with 95% confidence limits (6%, 27%). Two of these patients had severe complications: one of them required a temporary tracheostomy due to arytenoid edema and the other developed a laryngo-cutaneous fistula which healed after pharmacological treatment. Actuarial 3-year local-regional control was 59% (46%, 71%) and 3-year actuarial crude survival 55% (42%, 67%). There was no significant difference in the incidence of late complications or tumor control between the two groups of patients treated with a 4- or 6-h interval between the daily fractions. This study shows that the concomitant boost regimen tried here is feasible, but also stresses that the interval between dose fractions should be 6 h or more.