Treatment of carcinoma of the oral cavity with radical and postoperative radiotherapy at the Institute of Oncology Ljubljana, 1990–1995

SummaryAimTo evaluate the treatment results of squamous cell carcinoma of the oral cavity treated with radical or postoperative radiotherapy at the Institute of Oncology Ljubljana, in the period 1990–1995.Materials/MethodsThe medical records of patients were used to collect the data according to the predefined Data Acquisition Protocol. The impact of individual clinical and histopathological factors on the treatment outcome was evaluated by uni- and multivariate analysis.ResultsCombined therapy was performed in 142 patients, and 93 patients had radiotherapy only. In each of the two subgroups, the performance status of patients was assessed as “poor” in 7% and 30%; the proportion of T1–2 tumours was 53.6% and 16.1%, and the proportion of cN0-stage tumours was 38% and 29%. The 5-year survival without local failure in surgically treated and irradiated only patients was 89% and 30%, without neck failure 85.7% and 50.3%, without any failure 79.1% and 27.5%, and overall survival 43.9% and 11.5%, respectively (all P<0.0001). In multivariate analysis, the performance status and cT-stage emerged as independent prognostic factors for all four types of survival analyzed. The type of therapy retained its independent prognostic value only in the case of survival without local failure.ConclusionsThe only independent predictors of survival were performance status and cT stage, whereas the type of therapy impacted only local cure rate. The difference in survival results between the two treatments reflects primarily selection bias which occurred when patients were directed to one of the two treatment options