CA-PROM: Validation of a general patient-reported outcomes measure for Chinese patients with cancer.

•The developed scale was used as an effective evaluation tool for QoL of cancer patients.•Two methods, including classical test theory and item response theory (IRT) was used to select items.•The method of calculating validity for ordinal categorical PRO data of small sample size: OBID.•Explore potential subgroups and determine Risk thresholds of PRO.