Causes of failure of curative radiation therapy in 205 early glottic cancers.

A retrospective analysis of the results obtained with curative radiation therapy in a series of 205 patients affected by early glottic cancer treated from 1970 to 1985 at the Florence University and Hospital Departments of Radiotherapy is presented. All patients were staged according to TNM System (UICC 1978) as T1-T2 NO. The overall 5-year local control rates were 88% for T1a, 75% for T1b, and 64 for T2. The main cause of failure was progression or recurrence in T (41/48); five failures were observed in T and N at the same time and two in N. Of these 48 patients, 21 (44%) were salvaged with surgery. After surgical salvage of radiation failures, the 5-year survival rates were 95%, 91%, and 73%, respectively, for T1a, T1b, and T2. The extent of T and the number of subsites involved significantly affected local control. Vocal cord mobility was less important. The incidence of failures and damages was analyzed according to the radiation beam, the size of the irradiated volume, fractionation, and total tumor dose.