Evidence of survival benefit was often ambiguous in randomized trials of cancer treatments.

Objectives: The objective of the study is to estimate the proportion of statistically significant survival improvements reported in randomized trials of cancer treatments that are also compatible with a clinically negligible benefit.

Study Design And Setting: This is a cross-sectional study of reports of randomized clinical trials of cancer treatments that reported a statistically significant increase in overall survival, published in leading journals between 2009 and 2019. The main outcome variable was the hazard ratio (HR) for overall survival and its upper 95% confidence limit. An HR of 0.95 implies an absolute survival gain ≤1.9%, and an HR of 0.90 implies an absolute survival gain ≤3.8%; we reasoned that such survival gains can be considered clinically negligible, given the potential toxicity of oncologic treatments.

Results: Among 234 trial results, the mean point estimate of the HR was 0.664, and all HRs were below 0.90. The mean upper 95% confidence limit for the HR was 0.897, but 37.6% of the values were ≥0.95, and 59.0% were ≥0.90. These proportions were lower when overall survival was the primary outcome of the trial (29.9% ≥ 0.95 and 51.3% ≥ 0.90).

Conclusions: Considering only point estimates of HRs, all trials reported clinically meaningful improvements in overall survival. However, the upper confidence limits of a large proportion of HRs were also compatible with clinically negligible survival gains. Acknowledging the uncertainty regarding treatment benefits presents a challenge for the reporting of trial results and for clinical decision-making.