Defining radical cystectomy using the ICD-10 procedure coding system

•No consensus list of ICD-10-PCS codes to identify radical cystectomy (RC) exists.•We developed and internally validated a list of ICD-10-PCS codes to identify RC.•Identified 222/225 (99%) in training cohort and 227/234 (97%) in validation cohort.•Codes may be useful to bladder cancer researchers working with administrative data. The International Classification of Diseases-10-Procedure Coding System (ICD-10-PCS) is markedly more complex than the preceding ICD-9 system, which has increased the difficulty of identifying radical cystectomy (RC) in administrative datasets. Given the absence of a consensus code definition for RC, we sought to develop and internally validate a list of ICD-10-PCS codes for RC. All RCs performed from January 2019 to December 2020 were identified from our prospectively maintained registries and split into training (2019) and validation (2020) cohorts. A list of candidate ICD-10-PCS codes to identify RC were compiled using an online ICD-9 to ICD-10 converter. Codes were used to identify RCs from hospital billing data and referenced against registry cases in the training cohort; when discrepancies were found, the working ICD-10 code definition was iteratively revised. Accuracy of the consensus code list was verified in the validation cohort. We identified 459 RCs over the study period, including 225 in 2019 and 234 in 2020. In the training cohort, our codes identified 241 procedures, including 222 of 225 (99%) RCs performed for bladder cancer. Misidentified cases included 15 (6.2%) RCs for benign disease or nonurologic cancers and 4 (1.7%) non-RC cases. In the validation cohort we identified 239 cases, including 227 of 234 (97%) RCs for bladder cancer and 12 (5%) RCs for benign disease or nonurologic cancers. Given high fidelity to actual procedures performed, this list of ICD-10-PCS codes may be useful for researchers seeking to identify RC within administrative datasets.