Consistency Between State's Cancer Registry and All-Payer Claims Database in Documented Radiation Therapy Among Patients Who Received Breast Conservative Surgery.

PURPOSE: Arkansas is one of only four known states that have linked All-Payer Claims Database (APCD) to state's cancer registry (Arkansas Cancer Registry [ACR]). We evaluated the reporting consistency of radiation therapy (RT) between the two sources.

METHODS: Women age ≥ 18 years diagnosed in 2013-2017 with early-stage hormone receptor-positive breast cancer who received breast-conserving surgery were identified. Patients must have continuous insurance coverage (any private plans, Medicaid, and Medicare) in the 13 months (month of diagnosis and 12 months after). Receipt of RT was identified independently from ACR and APCD. We calculated sensitivity, specificity, positive predictive value, and negative predictive value for receipt of RT coded by the registry compared with APCD billing claims as the gold standard. We assessed the degree of concordance between the data sources by Cohen's kappa statistics.

RESULTS: The final sample included 2,695 patients who were in both databases and satisfied our inclusion/exclusion criteria. Using APCD as the gold standard, there were high sensitivity (88.1%) and positive predictive value (87.7%) and moderate specificity (71.1%) and negative predictive value (71.8%). The overall agreement between the two sources was 83.0%, with a kappa statistic of 0.59 (95% CI, 0.56 to 0.63). Consistency measures varied by age, stage, and insurance type with Medicare fee-for-service coverage only having the best and private insurance only the worse consistency.

CONCLUSION: In patients with early-stage hormone receptor-positive breast cancer who received breast-conserving surgery, recording of RT receipt was moderately consistent between Arkansas APCD and ACR. Future studies are needed to identify factors affecting reporting consistency to better use this unique resource in addressing population health problems.