Breast and colorectal cancer recurrence-free survival estimates in the US: Modeling versus active data collection

Background: A modeling method was developed to estimate recurrence-free survival using cancer registry survival data. This study aims to validate the modeled recurrence-free survival against "gold-standard" estimates from data collected by the National Program of Cancer Registries (NPCR) Patient-Centered Outcomes Research (PCOR) project.

Methods: We compared 5-year metastatic recurrence-free survival using modeling and empirical estimates from the PCOR project that collected disease-free status, tumor progression and recurrence for colorectal and female breast cancer cases diagnosed in 2011 in 5 U.S. state registries. To estimate empirical recurrence-free survival, we developed an algorithm that combined disease-free, recurrence, progression, and date information from NPCR-PCOR data. We applied the modeling method to relative survival for patients diagnosed with female breast and colorectal cancer in 2000-2015 in the SEER-18 areas.

Results: When grouping patients with stages I-III, the 5-year metastatic recurrence-free modeled and NPCR-PCOR estimates are very similar being respectively, 90.2 % and 88.6 % for female breast cancer, 74.6 % and 75.3 % for colon cancer, and 68.8 % and 68.5 % for rectum cancer. In general, the 5-year recurrence-free NPCR-PCOR and modeled estimates are still similar when controlling by stage. The modeled estimates, however, are not as accurate for recurrence-free survival in years 1-3 from diagnosis.

Conclusions: The alignment between NPCR-PCOR and modeled estimates supports their validity and provides robust population-based estimates of 5-year metastatic recurrence-free survival for female breast, colon, and rectum cancers. The modeling approach can in principle be extended to other cancer sites to provide provisional population-based estimates of 5-year recurrence free survival.