Accuracy of the HPV status site-specific factor 10 (SSF-10) variable for patients with oropharyngeal cancers in the Iowa Cancer Registry, 2010-2014

Abstract

Background: Surveillance, Epidemiology, and End Results Cancer Registries (SEER) began collecting human papillomavirus (HPV) status for upper aerodigestive tract cancers in 2010. However, classification of p16-testing was not included in the Collaborative Stage coding guidelines, potentially leading to inconsistent coding. Methods: The HPV values for Iowa patients with oropharyngeal cancers (n = 824) were recoded based on modified guidelines that included p16 test results, and compared with the original guidelines. Results: Forty percent of patients were recoded to a different value, and the HPV testing rate increased from 45% to 55%; 56% received p16-testing only. Of those originally coded as HPV-type 16 (n = 187), 89% were recoded to HPV-not otherwise specified (NOS). When comparing high-level positive/negative/not done categories, original coding captured 81% of patients with HPV-positive cancers. Conclusion: p16 was the most common HPV test but was inconsistently coded as HPV-testing. p16-positivity was also erroneously equated with HPV-type 16. Adding a separate p16 variable would improve consistency and accuracy of HPV coding.