Evaluating cancer survival among American Indian and Alaska Native patients living in Purchased/Referred Care Delivery Areas (PRCDA) and non-PRCDA counties

American Indian and Alaska Native (AIAN) cancer patients living in non-Purchased/Referred Care Delivery Areas (PRCDA) counties are less likely to be identified as AIAN. Consequently, AIAN cancer statistics are commonly restricted to PRCDA counties—potentially resulting in biased AIAN cancer statistics. We quantified differences in patient and tumor characteristics and survival between AIAN cancer patients living in PRCDA and non-PRCDA counties. We used geography-matched life tables to calculate age-standardized 60-month net relative survival for PRCDA versus non-PRCDA county AIAN residents aged 15 + years diagnosed with malignant cancers during 2005–2019. Patients were classified as AIAN if so identified by a reporting facility or linked to Indian Health Service records. We analyzed 197,078 tumors. Cancer survival was lower in PRCDA than non-PRCDA counties for many primary sites: leukemia (PRCDA = 0.492, non-PRCDA = 0.575), liver (PRCDA = 0.133, non-PRCDA = 0.205), non-Hodgkin lymphoma (PRCDA = 0.611, non-PRCDA = 0.710), pancreatic (PRCDA = 0.086, non-PRCDA = 0.133), stomach (PRCDA = 0.231, non-PRCDA = 0.293), and urinary bladder (PRCDA = 0.669, non-PRCDA = 0.730). Differences were also noted for screenable cancers: female breast, colorectal, lung and bronchus, and prostate, which generally persisted in stage-stratified analyses. Excluding non-PRCDA-resident AIAN cancer patients from cancer statistics results in data erasure for 3 in 10 AIAN cancer cases and may mask important differences in survival disparities among AIAN people by geography. These findings highlight the urgent need to improve AIAN race classification and monitor cancer statistics for all AIAN cancer patients.