Human Papillomavirus Testing in Head and Neck Squamous Cell Carcinoma: Impact of the 2018 College of American Pathologists Guideline Among Referral Cases at a Large Academic Institution.

CONTEXT.—: Given the growing clinical significance of human papillomavirus status in oropharyngeal squamous cell carcinoma, the College of American Pathologists established a set of evidence-based recommendations for high-risk human papillomavirus testing. OBJECTIVE.—: To evaluate the impact of the recommendations on human papillomavirus ancillary test ordering habits by comparing compliance before and after the guideline was published. DESIGN.—: We retrospectively reviewed head and neck squamous cell carcinoma biopsy or resection specimens from outside institutions during a 2.5-year period around guideline publication for whether or not human papillomavirus testing was performed in accordance with the guideline. RESULTS.—: Human papillomavirus testing deviated from the guideline in 45 of 107 cases (42.1%) before and 93 of 258 cases (36.0%) after their publication (P = .29). This included 6 of 26 cases of oropharyngeal squamous cell carcinoma (23.1%) before and 5 of 55 cases (9.1%) after (P = .16), with 5 of 5 (100.0%) after due to not performing p16 immunohistochemistry. This also included 30 of 68 cases of nonoropharyngeal carcinoma (44.1%) before and 69 of 163 (42.3%) after the guideline was published (P = .88), with 29 of 30 (96.7%) before and 67 of 69 (97.1%) after due to unnecessary use of p16 immunohistochemistry. Nodal metastasis testing deviated in 9 of 13 cases (69.2%) before and 19 of 40 cases (47.5%) after (P = .21) with marked variability in testing, including 3 of 9 (33.3%) before and 8 of 19 (42.1%) after, for not confirming certain p16 immunohistochemistry-positive tumors with human papillomavirus-specific testing. CONCLUSIONS.—: Pathologists continue to deviate from the testing guideline significantly in everyday practice. Further education and discussion about the appropriate handling of head and neck cancer specimens may be needed.