[1145] Integration of HPV Testing into the Standard Pathology Assessment of Head and Neck Cancer

AD Singhi, WH Westra. The Johns Hopkins Medical Institutions, Baltimore, MD

Background: Human papillomavirus 16 (HPV16) has recently been confirmed as a causative agent in the development of a subset of head and neck squamous cell carcinomas (HNSCCs). These HPV16-positive tumors have a clinical profile that diverges from that of HPV16-negative HNSCCs including response to therapy. Accordingly, HPV testing may soon become integrated into the standard pathologic assessment of HNSCCs. We report a clinical experience of prospective HPV testing in patients with HNSCC.
Design: Pathologic and clinical data was prospectively collected for all patients with HNSCC that had undergone HPV testing at the Johns Hopkins Hospital as part of clinical care during a 51 month period (6/2004 9/2008). Standard HPV testing included p16 immunohistochemistry (IHC), HPV16 in-situ hybridization (ISH), and wide spectrum HPV ISH for p16 positive/HPV16 negative cases.
Results: HPV analysis was performed on 195 HNSCCs to facilitate tumor localization (21%) and tumor subclassification (10%), determine patient eligibility for HPV vaccine trials (10%), satisfy patient curiosity (7%), and estimate treatment response (52%). Patients ranged in age from 28 to 82 years (median, 54; mean, 54); and 145 (74%) were male. Overall, 135 (69%) tumors were HPV16-positive. HPV positivity correlated with oropharyngeal site (81% vs. 2%, p < .0001) and male gender (p = .002). Indeed, for men with oropharyngeal carcinoma, the HPV-positivity rate was 85%. The correlation between HPV16 detection and p16 overexpression was 95%: All HPV16-positive cases were strongly p16 positive; however p16 positivity was present in 25% of the HPV16-negative cases. In 45% of these discordant cases, high p16 expression was due to the presence of some other HPV type.
Conclusions: Our prospective experience with HPV testing in the clinical arena confirms HPV16 as an important agent in oropharyngeal carcinomas. HPV status is becoming an increasingly important parameter in the pathologic evaluation of HNSCCs: testing is frequently requested by the oncologist to estimate response to therapy and clinical outcome, and by the pathologist as a tool to aid tumor classification and discern tumor origin. A rational and feasible detection strategy that incorporates both p16 IHC and HPV ISH is able to detect HPV in a remarkably high percentage of oropharyngeal cancers.
Category: Head & Neck

Monday, March 9, 2009 1:00 PM

Poster Session II # 169, Monday Afternoon