Background: PRO endpoints are increasingly being used in cancer RCTs. However, the PRO assessment in such trials often suffers from serious methodological shortcomings, and the results seldom impact on clinical policy or practice. Methods: We performed a systematic review to identify RCTs with a PRO endpoint in breast, colorectal, lung, prostate, gynaecological and bladder cancer. A checklist score for quality of PRO reporting (ranging between 0-100), based on that of the International Society for Quality of Life Research (ISOQOL) and the CONSORT PRO extension, was computed for each RCT. Analyses were also conducted by type of PRO endpoint (primary versus secondary) and year of publication (i.e. before and after the publication of the CONSORT PRO extension). Results: We identified 610 RCTs with a total of 323,482 patients. PROs were most frequently used in RCTs of breast (N = 176), followed by lung (N = 123), prostate (N = 108), colorectal (N = 103), gynaecological (N = 83) and bladder (N = 17) cancer. Quality of PRO reporting (mean score: 56.4) was highest in RCTs conducted in prostate cancer (PCa) (Table). Regardless of cancer type, quality of reporting was typically higher in RCTs where PROs were primary endpoints. Quality of reporting was higher for RCTs published after the CONSORT PRO Extension (2013), with the exception of RCTs conducted in PCa, where quality was stable over time. Conclusions: PRO reporting of RCTs conducted in PCa has better quality than in the other cancer sites that were reviewed. Regardless of cancer site, quality of PRO reporting has improved after the publication of the CONSORT PRO Extension.

^†Wilcoxon-Mann-Whitney test was used