Development and Evaluation of a Multisource Approach to Extend Mortality Follow-Up for Older Adults With Advanced Cancer Enrolled in Randomized Trials

PURPOSE Mortality data can complement primary end points from cancer clinical trials. Yet, identifying deaths after trial completion is challenging, as timely and comprehensive vital status data are unavailable in the United States. We developed and evaluated a multisource approach to capture death data after clinical trial completion. METHODS Individuals age 70 years and older with incurable solid tumors or lymphoma and ≥1 aging-related condition were enrolled from October 2014 to March 2019 (ClinicalTrials.gov identifier: NCT02107443 and NCT02054741 ). Participants provided consent to link trial information to external sources. We developed a stepped approach for extended death capture using (1) active trial follow-up up to 1 year, (2) linkage to the National Death Index (NDI), and (3) obituary searches, thus generating a 5-year survival curve. In a random sample of 50 participants who died during trial follow-up, we estimated sensitivity of death data using NDI and obituary sources and computed survival times by data source. RESULTS The two trials enrolled 1,169 participants; mean age was 76 years; 46% were female; and gastrointestinal cancer (30%) and lung cancer (26%) were the most common cancer types. Across data sources, maximum follow-up was >7 years; 5-year survival was 18%. In total, there were 841 deaths: 603 identified during trial follow-up; 199 from the NDI; and 39 from obituary searches. The sensitivity for death capture was 92% for the NDI and 94% for the obituary searches compared with the trial data, and computed survival times were similar across data sources. CONCLUSION Extending clinical trial mortality follow-up through linkage with external data sources was feasible and accurate. Future cancer clinical trials should collect necessary consent and patient identifiers for vital status linkages that can enhance understanding of longer-term outcomes.