Prognostic significance of Ki-67 in salivary gland carcinomas.

BACKGROUND: Salivary gland carcinomas are a heterogeneous group of tumors with varying malignant potential. In this study, we evaluated the proliferative marker Ki-67 in salivary gland carcinomas and related the Ki-67 index to clinical data. METHODS: A total of 176 salivary gland carcinomas of 13 different subtypes were stained immunohistochemically for Ki-67. The number of Ki-67 positive cells was counted and the Ki-67 index was calculated as the percentage of positive tumor cells. RESULTS: The Ki-67 median value was 26 (range 1-99). The median follow-up time was 6.9 years (range 0-19 years). The 5- and 10-year crude survival was 70% and 59%, respectively. In univariate analysis, Ki-67 index, stage, vascular invasion and tumor grade were significantly related to crude survival, but in multivariate analysis only Ki-67 index, age, and stage were independent prognostic factors. CONCLUSION: We showed that irrespective of subtyping, grading or morphological appearance of tumor, the Ki-67 index is an important and independent prognosticator. Clinical and histo-pathological data must be considered, when planning the treatment of the individual patient. We have shown that besides stage and age of the patient, Ki-67 is a strong, independent prognostic factor.