Evaluation of the attributable fraction and burden of HPV-related oropharyngeal cancers in Greece-the ORPHEAS study

Background: Herein, we evaluated the attributable fraction (AF) of human papillomavirus (HPV)-mediated (HPV+) oropharyngeal carcinomas (OPCs) in Greece over a recent calendar period.

Patients and methods: ORPHEAS, a retrospective, observational, multicenter, cross-sectional study with prospective recruitment, included adult patients with OPC in 2017-2022, each of them with a high-quality, treatment-naïve tumor specimen. The primary endpoint was the HPV-AF, defined as combined positivity for p16^INK4a (p16) overexpression and HPV DNA presence by central laboratory testing, among included patients. Other endpoints evaluated the HPV+/HPV- patient/disease characteristics at OPC diagnosis and the HPV subtypes for HPV+ patients.

Results: 144/147 patients with available HPV status by central laboratory testing were analyzed [median age: 60.0 years; males: 111 (77.1%)]. The most common tumor anatomical sites were the tonsils (70/147, 48.6%) and the base of the tongue (51, 35.4%), and most patients were at the American Joint Committee on Cancer eighth edition TNM (tumor-node-metastasis) stages III (25, 22.7%) and IV (43, 39.1%). The HPV-AF was 52.1% (75/144; 95% confidence interval 43.6% to 60.5%). Most HPV+ patients were infected by an HPV type targeted by the 9-valent HPV vaccine (72/75, 96.0%), especially HPV16 (70/75, 93.3%). HPV+ compared with HPV- patients were younger (median age 58.0 versus 64.0 years; P = 0.003); more likely to have tumors in the tonsils (65.0% versus 30.4%; P < 0.001); less likely to have tumors in the base of the tongue (25.3% versus 46.4%; P = 0.008); and less frequently at TNM stage IV (20.4% versus 57.1%; overall P < 0.001).

Conclusions: In Greece, we observed a high HPV-AF (52.1%) in OPC, approximating the AFs reported for some Northern European countries. HPV+ versus HPV- patients were younger, more frequently with tonsillar tumors, and less frequently at TNM stage IV. Since most patients were infected by ≥1 HPV type targeted by the 9-valent vaccine, the HPV+ OPC burden could be mitigated through a routine HPV gender-neutral vaccination program.