Using Data on Tumor Grade in Cancer Registries to Enhance Surveillance of Oropharyngeal Cancers in Relation to the Human Papillomavirus Epidemic.

BACKGROUND

Incidence rates have been increasing in US whites for squamous cell carcinoma (SCC) at anatomic sites involving the oropharynx (OP) and classified as potentially associated with human papillomavirus (HPV). Registries have not routinely collected data on HPV status of tumors. High tumor grade (poorly differentiated or undifferentiated), however, has been associated with HPV positivity in clinical studies. This study explored the potential value of adding data on tumor grade to registry-based surveillance efforts.

METHODS

Data were obtained on tumor grade for 39,907 OP SCCs diagnosed in 2000-2012 at HPV-associated OP sites in a research database for Surveillance, Epidemiology, and End Results (SEER) Program registries. Grade was compared by anatomic site. Annual percent change in the age-standardized incidence rate was estimated by joinpoint regression.

RESULTS

HPV-associated OP SCC sites were predominantly (87%) base of tongue and tonsils (BTT). High-grade comprised 40% for BTT vs 20%-30% for other HPV-associated sites. Temporal increases in total rates for BTT were evident for whites, who had statistically significant increases for high grade but persistently low rates for low grade. Rates increased for unknown grade, reflecting a decline in cancer-directed surgery.

CONCLUSIONS

Findings support the use of tumor grade for surveillance of OP SCC in relation to the HPV epidemic. Future studies should include non-SEER registries, and also examine HPV status for unknown grade and consistency in grading among pathologists.