PT - JOURNAL ARTICLE AU - WOLFF, JOHANNES E. TI - Anemia in Placebo Arms of Cancer Studies AID - 10.21873/anticanres.15266 DP - 2021 Sep 01 TA - Anticancer Research PG - 4543--4548 VI - 41 IP - 9 4099 - http://ar.iiarjournals.org/content/41/9/4543.short 4100 - http://ar.iiarjournals.org/content/41/9/4543.full SO - Anticancer Res2021 Sep 01; 41 AB - Background/Aim: Adverse event (AE) frequencies observed in interventional clinical trials are difficult to interpret when the placebo control is missing. Materials and Methods: Systematic literature review of AEs reported from the placebo arms of randomized cancer trials between 2008 and 2021. Imputation of missing values assuming normal distribution of hemoglobin values. Results: Anemia grade 1 or higher was reported in 46 of 100 placebo monotherapy cohorts with a mean frequency of 23.4% (SD=27%) of the enrolled patients. The reported frequency depended on the type of cancer; other demographic variables had no significant influence on anemia frequency. Conclusion: External controls for anemia in clinical trials should be disease specific.