p53 overexpression is not an independent prognostic factor for patients with primary ovarian epithelial cancer

BACKGROUND. The clinical significance of p53 overexpression in patients with ovarian carcinoma is uncertain. Previous studies have yielded conflicting results and have been hampered by small patient populations, failure to account for other well-known prognostic variables in multivariate analysis, and failure to account for the grade of p53 overexpression. The aim of this study was to investigate the independent prognostic significance of p53 overexpression in patients with primary ovarian epithelial cancer (POEC). METHODS. Tumors obtained from 221 patients with primary ovarian epithelial cancer (POEC) (Stages I-IV) were studied for p53 overexpression semiquantitatively by immunohistochemical techniques. The median duration of follow-up of surviving patients was 7 years. The presence or absence and degree of p53 overexpression were correlated with the clinicopathologic features of the study population and overall survival. Survival curves were constructed according to the Kaplan-Meier method, and differences in survival were assessed with the log rank test. The prognostic significance of p53 overexpression for survival was assessed in a multivariate analysis with the Cox proportional hazards model. RESULTS. One hundred seven tumors (48.4%) exhibited p53 overexpression. The overexpression was graded as mild in 16.7% of cases, moderate in 5.9%, and strong in 25.8%. p53 overexpression was associated with advanced stage (P = 0.04), higher grade (P = 0.0003), serous histology (P = 0.0018), and patient age > 61 years (P = 0.013). In univariate analysis, p53 overexpression was a significant prognostic factor (P = 0.049 for any degree of overexpression, P = 0.03 for strong overexpression). However, in multivariate analysis, after adjustment for stage and size of residual tumor following cytoreductive surgery, p53 overexpression did not retain statistical significance. Survival curves for patients with different stages and grades of tumor differentiation did not demonstrate a difference in survival among patients with no p53 overexpression, compared with those who demonstrated any degree of p53 overexpression or compared with those who demonstrated strong p53 overexpression. CONCLUSIONS. p53 overexpression is not an independent prognostic factor for patients with primary ovarian epithelial cancer. (C) 1997 American Cancer Society.