Radiation therapy for early glottic cancer (T1N0M0): II. Prospective randomized study concerning radiation field.
A prospective randomized study to determine the effect of radiation field on the local control of early glottic cancer was performed. From May 1982 through December 1985, a total of 87 patients with early glottic cancer (T1N0M0) were treated at our department with an individualized wedge filter technique using a shell to improve the dose distribution and immobilization during radiotherapy with 4 MV X ray. Patients were randomly allocated to either treatment group A (radiation field size: 5 x 5 cm2) or B (6 x 6 cm2) using bilateral parallel opposed portals. Total radiation dose administered was 60 Gy in 30 fractions over a 6-week period. The 3-year recurrence-free survival rates were 93% in group A and 96% in group B (no significant difference). Comparison with historical control showed that both arms achieved better results. These results were mainly due to the improved local control of whole-length lesions of single vocal cords. Acute mucosal reaction (p less than 0.05) and persistent arytenoid edema lasting more than 6 months (p less than 0.02) were more frequently observed in group B than in group A. It is concluded that the critical factor in getting optimal results in the treatment of early glottic cancer is careful attention to the technique of treatment.
Department of Radiation Therapy, Center for Adult Diseases, Osaka, Japan.
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Teshima
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Chatani
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Inoue
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005500:Follow-Up Studies; D005931:Glottis; D006801:Humans; D015994:Incidence; D007822:Laryngeal Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D007825:Laryngectomy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000601:surgery; D011446:Prospective Studies; D011832:Radiation Injuries / Q000453:epidemiology; D016032:Randomized Controlled Trials as Topic