Radiation treatment of laryngeal carcinoma with special reference to CRE values

In a retrospective analysis of 203 cases of laryngeal carcinoma treated with radiation therapy, conventional absorbed dose levels and CRE calculations were compared as regards the prediction of treatment failure, tumor recurrences and major complications. The recurrence rate for T1 and T2 tumors was 14 per cent and for T3-4 tumors 26 per cent. Poorly differentiated (grade 3) tumors had a significantly higher recurrence rate than well and moderately well differentiated (grades 1 and 2) ones. Corrected 10-year survival rates were 89, 82 and 52 per cent, respectively for T1, T2 and T3-4 tumors. There was a significant relationship between the recurrence rate and the CRE level while the total absorbed dose in Gy or the size of the treatment field could not be correlated to treatment failure. Major complications occurred in 8 (3.9%) patients and they had all received treatment giving CRE values of 1920 reu or more.