Independent prognostic factors of 861 cases of oral squamous cell carcinoma in Korean adults.

Oral squamous cell carcinoma (OSCC) accounts for 4.5% of all malignant tumors in Korean males and 3.5% in Korean females. The high recurrence rate, and in particular the high local recurrence rate, constitutes a major therapeutic problem for the Korean population, yet there is a paucity of reports addressing the independent predictors of response and survival rate of OSCC in Korea. The present study was designed to investigate the prognostic value of clinical and demographic data within a set of 861 cases of OSCC in Korea. The medical records of 861 OSCC patients who received treatment between 1984 and 1996 at 22 Korean hospitals were reviewed retrospectively with respect to several patient characteristics, including age at diagnosis, gender, location, TNM stage, and treatment. Independent patient-related and treatment-related factors that significantly influenced disease outcome after treatment were analyzed. To assess the independent factors affecting survival rate, univariate and multivariate regression analyses of the survival data were performed using the Cox proportional hazards model. A tree-structured survival model was also derived using survival tree with unbiased detection of interaction (STUDI). The multivariate Cox regression analysis showed that age, gender, composite stage, and treatment method were significant independent prognostic factors. Radiation dose, stage, size of tumor mass, and age of patient also strongly impacted survival time. OSCC is an extremely malignant carcinoma whose prognostic factors are multiple and complex. Based on the findings of this study, we believe that the prognosis of OSCC might depend directly on cancer stage as determined by the TNM system. Furthermore, the survival rate is positively affected by treatment of the neck upon presentation of the cancer, as this can prevent late neck disease due to persistent growth of occult metastases.