A Systematic Review of p53 as a Prognostic Factor of Survival in Squamous Cell Carcinoma of the Four Main Anatomical Subsites of the Head and Neck

Objectives: To summarize existing evidence about whether the presence of mutant or upregulated p53 is a prognostic factor for patients presenting with squamous cell carcinoma arising from the larynx, oropharynx, hypopharynx, or oral cavity. Method: Relevant articles were identified using strict criteria for systematic searches. Associations between mutant or upregulated p53 versus wild-type or low/undetectable p53 in relation to overall survival and DFS were summarized by extracting or deriving hazard ratio (HR) estimates. Random-effects meta-analyses were used to account for between-study heterogeneity and to summarize the effect of p53 across studies. Results: The meta-analyses gave a statistically significant pooled HR for overall survival in oral cavity [pooled HR, 1.48; 95% confidence interval, (95% CI), 1.03-2.11], and for disease-free survival in oral cavity (pooled HR, 1.47; 95% CI, 1.12-1.93) and in oropharynx (pooled HR, 0.45; 95% CI, 0.27-0.73). Despite attempts to limit it, between-study heterogeneity was large in the majority of meta-analyses and the prognostic value of p53 was generally inconsistent and inconclusive across studies. Conclusion: The meta-analysis results highlight that current evidence about the prognostic value of p53 in patients with squamous cell carcinaoma of the head and neck is inconclusive. Large heterogeneity exists across studies in study-level and patient-level characteristics, making it difficult to ascertain a clear picture. Future studies are required in which p53 expression is investigated in a more standardized and biologically informative manner. In particular, prospectively planned individual patient data meta-analyses are needed to establish the prognostic importance of p53 for specific subgroups of patients undergoing specific treatments. Cancer Epidemiol Biomarkers Prev; 19(2); 574-87. (C) 2010 AACR.