Ki-67 expression predicts radiosensitivity in oral squamous cell carcinoma

The prognostic relevance of Ki-67 expression in oral squamous cell carcinoma (OSCC) is still controversial. As proliferating cells are more susceptible to ionizing radiation, the authors investigated if a high proliferation rate reflected by Ki-67 expression, predicts radiosensitivity in OSCC patients. In 52 patients with OSCC who received primary surgery followed by radiation therapy, the proliferation rate was assessed by Ki-67 immunhistochemistry and correlated to recurrent free survival and overall survival. Low proliferative carcinomas showed a significantly shorter mean time to recurrence of 27.5 months compared to 49.5 months of high proliferative tumours (p = 0.048). The 5-year survival rate of low proliferative tumours was 49% compared to 80% for high proliferative tumours (p = 0.042). This study indicates that tumours with high proliferative activity are more susceptible to radiation therapy. Ki-67 might be used as a marker to predict the response to radiation therapy in patients with OSCC.