Meta-analysis of cancer stage compared with mortality as end points in randomized clinical trials of cancer screening

Randomized clinical trials of cancer screening typically use cancer-specific mortality as the primary end point. The incidence of stage III-IV cancer is a potential alternative end point that may accelerate completion of trials. In a systematic review and meta-analysis that included 41 randomized clinical trials of cancer screening, correlation between the reduction in stage III and IV cancer and the reduction in cancer-specific mortality varied by cancer type. The correlation was high in trials that screened for ovarian (Pearson p=0.99) and lung (0.92) cancers, moderate for breast cancer (0.70), and weak for colorectal (0.39) and prostate (-0.69) cancers. The authors conclude that the end point of late-stage cancer may be an appropriate alternative to cancer-specific mortality for randomized clinical trials of screening for some types of cancer, but not for others.