Prognostic factors for local control in nasopharyngeal cancer (NPC): analysis by multivariate proportional hazard models.

ABSTRACT

Despite the development of meticulous radiation therapy techniques, the local control of the nasopharyngeal cancer (NPC) remains unsatisfactory. We examined retrospectively the clinicopathologic factors which have impact upon local recurrence-free survival (LRFS) of the 67 patients with NPC who had been irradiated greater than or equal to 40 Gy with curative intent from 1975 through 1988. Three-year LRFS rate was 63%. T stage, histology, the presence of accompanying lymphocytic infiltration, and the properness of radiation therapy had influence upon LRFS with a statistical significance. Multivariate proportional hazard models showed that T stage and pathology retained significance. Radiation therapy properness emerged as a third factor when only the patients irradiated greater than or equal to 60 Gy were included in the analysis. From these results, three groups with low, moderate, and high risk of shortened LRFS could be separated. This risk classification could contribute to the stratification criteria of future study for the improvement of local control by new modalities.