Grant: Master's Award: Canada Graduate Scholarships

Loss to follow-up (LTFU) happens when participants in clinical trials drop out, making it difficult to assess their treatment outcomes. This issue is particularly important in cancer trials, as it can distort the results and affect the reliability of treatment effect estimates. Despite its potential impact, LTFU is often underreported in clinical studies. A review of 235 trials found that in many cases, assuming a worst-case scenario for LTFU would change the study main conclusions. Smaller trials are especially vulnerable to the effects of LTFU.The Canadian Cancer Trials Group (CCTG) has conducted over 200 phase III cancer trials, which include detailed data on LTFU, including when it happens, who it happens to, and the reasons for it. This presents a valuable opportunity to better understand how LTFU influences trial outcomes. The goal of this study is to document the rate of LTFU in CCTG cancer trials and analyze its impact by looking at the involvement of factors, such as cancer type, disease stage, treatment type, and length of study. This study aims to answer three key questions: (1) What are the overall and subgroup-specific rates of LTFU? (2) How does LTFU affect the estimated treatment effect? (3) What baseline factors are linked to higher or lower LTFU rates?The hypothesis is that LTFU varies based on factors like treatment type and cancer stage, and that it can bias treatment effect estimates. The study will analyze data from 150-200 CCTG trials, using advanced statistical methods to evaluate the impact of LTFU on trial results and to identify characteristics that predict LTFU. The findings will help improve how LTFU is reported in trials, with implications for drug approval, clinical guidelines, and the overall reliability of clinical research.