RADIATION-THERAPY FOR GLOTTIC CANCER USING 6-MV PHOTONS

BACKGROUND, It has been recommended that cobalt-60 or 4-MV photons be used when treating glottic cancer with radiation therapy. Underdosing may occur when using higher energy photons, particularly when the ante rior commissure is involved. The authors report their experience using higher energy photons (6 MV) for the treatment of glottic cancer. MET HODS, Between January 1975 and July 1991, 73 patients with Tis, T1, T2 , or T3 glottic tumors underwent radiation therapy with curative inten t. Cobalt-60 or 4-MV photons were used to treat the cancers of 30 pati ents, and 6-MV photons were used to treat 43 patients. Clinical record s were reviewed retrospectively to determine patterns of treatment fai lure, cancer deaths, and local tumor control in the 43 patients receiv ing treatment with 6-MV photons. Patients were followed until death or for a minimum of two years. RESULTS. Treatment failures were: local r ecurrence, one patient; local recurrence and distant metastasis, one p atient; delayed neck metastasis, two patients; and delayed neck metast asis with distant metastasis, one patient. Three patients who had trea tment failure are alive and free of cancer after salvage treatment. Tw o patients died of neck and distant metastases. The 2-year initial loc al tumor control rate was 94.8%. CONCLUSIONS. Glottic cancer can be tr eated successfully with 6-MV photons. Local tumor control is similar t o that reported using cobalt-60 or 4-MV photons. (C) 1996 American Can cer Society.