Prevalence of missing data in the National Cancer Database and association with overall survival

Abstract

AbstractImportanceCancer registries are important real-world data (RWD) sources that rely on data abstraction from the medical record, however, patients with unknown or missing data are under-represented in studies that use such data sources.ObjectiveTo determine the prevalence of missing data and its associated overall survival among cancer patientsDesign, Setting, and ParticipantsIn this retrospective cohort study, all variables within the National Cancer Database (NCDB) were reviewed for missing or unknown values for the three most common cancers in the United States diagnosed from 2006 to 2015. Prevalence of patient records with missing data and their associated overall survival were determined. Data analysis was performed from February to August 2020.ExposuresAny missing data field within a patient record among 63 variables of interest, from over 130 variables total in the NCDB.Main Outcome and MeasurePrevalence of cancer patient records with missing data and associated two-year overall survivalResultsA total of 1,198,749 non-small cell lung cancer (NSCLC) patients (mean [SD] age, 68.5 [10.9] years; 569,938 [47.5%] women), 2,120,775 breast cancer patients (mean [SD] age, 61.0 [13.3] years; 2,101,758 [99.1%] women), and 1,158,635 prostate cancer patients (mean [SD] age, 65.2 [9.0] years; 0 [0%] women) were included for analysis. For NSCLC, there were 851,295 (71.0%) patients with missing data in variables of interest; 2-year overall survival was 33.2% for patients with missing data and 51.6% for patients with complete data (p<0.001). For breast cancer, there were 1,161,096 (54.7%) patients with missing data; 2-year overall survival was 93.2% for patients with missing data and 93.9% for patients with complete data (p<0.001). For prostate cancer, there were 460,167 (39.7%) patients with missing data; 2-year overall survival was 91.0% for patients with missing data and 95.6% for patients with complete data (p<0.001).Conclusions and RelevanceWithin a large cancer registry-based RWD source, missing data that was unable to be ascertained from the medical record was highly prevalent. Missing data among cancer patients was associated with heterogeneous differences in overall survival. Improving documentation and data quality are needed to best leverage RWD for clinical advancements.