Prognostic factors in T3 glottic cancer.
A detailed statistical analysis of prognostic factors influencing the local control rate by irradiation in T3 glottic cancer is presented. This has been done to identify favorable and unfavorable prognostic factors in order to precisely identify areas where new treatment strategies are needed. Between 1963 and 1977, 110 patients with T3NOMO glottic cancer were treated with radical radiotherapy with surgery for salvage. Only one of 12 women recurred following irradiation compared with 50 recurrences so far among the 98 men (P = 0.006). The recurrence rate among men using an NSD of less than 1700 rets was significantly higher than when an NSD of greater than 1700 rets was used (P = 0.022). This difference remained significant even after correction for other possible confounding variables. The recurrence rate among men over the age of 60 years was significantly lower than in men under 60 (P = 0.022). This difference in local control is due to a high proportion of patients with residual disease following irradiation. Factors not found to be of significance included radiation field size, superficial extent of disease, and tracheostomy before or during treatment. No difference in surgical salvage between the residual and recurrent disease cases has been seen. The cause of failure to respond to irradiation is discussed and possible ways to improve the local control by irradiation, particularly in young males, are suggested.
D000328:Adult; D000367:Age Factors; D000368:Aged; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005931:Glottis; D006801:Humans; D007822:Laryngeal Neoplasms / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011379:Prognosis; D012306:Risk; D012737:Sex Factors