p53 and Ki-67 as predictive markers for radiosensitivity in squamous cell carcinoma of the oral cavity? An immunohistochemical and clinicopathologic study

Purpose: Previously published data relating the expression of p53 and Ki-67 to radiation response in head and neck cancer are conflicting. This may be due to differences in patient selection and treatment modalities. In this study of a homogenous population of patients with oral cavity cancer, Ki-67 and p53 indices were correlated with histopathologically assessed tumor re gression after preoperative radiochemotherapy and longterm outcome. Methods and Materials: Eighty-eight patients with squamous cell carcinoma o f the oral cavity and treated between September 1985 and November 1995 by p reoperative radiochemotherapy and definitive surgery were included in this analysis. By immunohistochemistry (IHC) the pre-irradiation expression of p 53 and of Ki-67 were analyzed and correlated with the histopathologically p roven tumor regression, overall survival and local control. Results: The overall 2- and 5-year survival rates were 76.5% and 63%, the l ocoregional control rates were 84% and 79%, respectively. After preoperativ e radiochemotherapy 29 patients (33%) showed complete tumor regression (ypT (0) classification). Survival and local control rates were significantly hi gher for patients showing ypT(0) classification than ypT(1-4) classificatio n (p < 0.01). This effect was independent of pretreatment tumor classificat ion in multivariate analysis. Pre-irradiation p53 status and Ki-67 index ha d no influence on tumor regression and clinical outcome in these patients. Conclusions: Complete tumor regression after preoperative treatment is rela ted to an improved outcome in combined modality treatment of oral cavity ca ncer. The presented study could not demonstrate an influence of p53 and Ki- 67 status as detected by immunohistochemical staining on survival, local co ntrol, or tumor regression after radiochemotherapy. (C) 2001 Elsevier Scien ce Inc.