Role of p53 as a prognostic factor for survival in lung cancer: a systematic review of the literature with a meta-analysis

The role of p53, as a prognostic factor for survival in lung cancer, is con troversial and the purpose of the present systematic review of the literatu re is to determine this effect. Published studies were identified with the objective to aggregate the avail able survival results after a methodological assessment using a scale speci fically designed by the European Lung Cancer Working Party (ELCWP). To be e ligible, a study had to deal with p53 assessment in lung cancer (primary si te) only, and to provide a survival comparison according to the p53 status. Among the 74 eligible papers, 30 identified p53 abnormalities as a univaria te statistically significant poor prognostic factor and 56 provided suffici ent data to allow survival results aggregation. There was no significant di fference between the trials that either showed or did not show a prognostic effect of p53 according to the methodological score or to the laboratory t echnique used. The studies were categorized by histology, disease stage, tr eatment and laboratory technique. Combined hazard ratios suggested that an abnormal p53 status had an unfavourable impact on survival: in any stage no nsmall cell lung cancer (NSCLC) the mean (95% confidence interval) was 1.44 (1.20-1.72) (number of studies included in the subgroup was 11), 1.50 (1.3 2-1.70) in stages I-H NSCLC (n=19), 1.68 (1.23-2.29) in stages I-IIIB NSCLC (n=5), 1.68 (1.30-2.18) in stages III-IV NSCLC (n=9), 1.48 (1.29-1.70) in surgically resected NSCLC (n=20), 1.37 (1.02-1.85) in squamous cell carcino ma (n=9), 2.24 (1.70-2.95) in adenocarcinoma (n=9), 1.57 (1.28-1.91) for a positive immunohistochemistry with antibody 1801 (n=8), 1.25 (1.09-1.43) fo r a positive immunohistochemistry with antibody DO-7 (n=16), and 1.65 (1.35 -2.00) for an abnormal molecular biology test (n=13). Data were insufficien t to determine the prognostic value of p53 in small cell lung cancer. In each subgroup of nonsmall cell lung cancer, p53 abnormal status was show n to be associated with a poorer survival prognosis.