TY - JOUR T1 - Anemia in Placebo Arms of Cancer Studies JF - Anticancer Research JO - Anticancer Res SP - 4543 LP - 4548 DO - 10.21873/anticanres.15266 VL - 41 IS - 9 AU - JOHANNES E. WOLFF Y1 - 2021/09/01 UR - http://ar.iiarjournals.org/content/41/9/4543.abstract N2 - 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. ER -