Association between event-free survival and overall survival after neoadjuvant treatment for non-small cell lung cancer: a systematic review and meta-analysis.

BACKGROUND: We wanted to evaluate if event-free survival (EFS) is a reliable surrogate for overall survival (OS) in patients with resectable non-small cell lung cancer (r-NSCLC) receiving neoadjuvant therapy. We conducted a systematic literature review and meta-analysis to investigate the statistical association between EFS and OS. RESEARCH DESIGN AND METHODS: Electronic databases were searched on 30 July 2021 to identify sources reporting both EFS and OS data in patients with stage I-IIIB r-NSCLC receiving neoadjuvant therapy. Correlation and regression analyses evaluated the association between the effect of treatment on EFS and OS using log-hazard ratios (HRs). Sources in which the entire population had epidermal growth factor receptor mutations were excluded from the analyses. RESULTS: We identified 74 sources, of which 8 reported EFS and OS HRs from randomized controlled trials. Based on these, we found a positive linear correlation and a strong association between EFS and OS log-HRs (weighted Pearson's correlation coefficient r = 0.864; 95% confidence interval 0.809-0.992; P = 0.006; random-effects meta-regression, R2 = 0.777). CONCLUSIONS: We found a strong association between treatment effects for EFS and OS, indicating that improvements in EFS are likely to be predictive of improvements in OS. EFS may therefore be a reliable surrogate for OS after neoadjuvant therapy in r-NSCLC.

Investigation of DNA repair pathway activity.

DNA is constantly being damaged from endogenous and exogenous sources and efficient repair of different types of DNA lesions is essential for the survival of the organism. Dictyostelium is highly resistant to DNA damage and its genome sequence has revealed the presence of multiple repair pathways conserved with vertebrates but lost in other genetically tractable invertebrate models. As such, Dictyostelium is a powerful model organism to study selected human DNA repair pathways and may provide insights into the molecular basis of how cells become resistant to DNA damage. Here we describe a range of assays used to study DNA repair in Dictyostelium. Genes required for repair of DNA damage can be identified and analyzed by comparing the ability of control or mutant cells to survive exposure to genotoxic agents that induce different types of DNA lesion. We also describe assays that assess the presence of markers for DNA repair within chromatin either in the form of posttranslational modification of proteins at sites of damage or the recruitment of repair factors to DNA lesions. Finally, we also describe more direct assays to assess repair of DNA double-strand breaks by either homologous recombination or non-homologous end joining.