Human papillomavirus (HPV) load is higher in HPVDNA/p16 positive than in HPVDNA positive/p16 negative oropharyngeal squamous cell carcinoma but does not differ significantly between various subsites or correlate to survival.

Objective: Patients with human papillomavirus DNA positive (HPVDNA) and p16 overexpressing (p16) oropharyngeal squamous cell carcinoma (OPSCC), especially those with cancer in the tonsillar and base of tongue subsites as compared to other OPSCC subsites have a better outcome than those with only HPVDNA or only p16 cancer. Likewise having a high viral load has been suggested to be a positive prognostic factor. We therefore hypothesized, that HPV viral load could vary depending on OPSCC subsite, as well as with regard to whether the cancer was HPVDNA and p16, or only HPVDNA, or only p16 and that this affected outcome.

Material And Methods: To address these issues HPV viral load was determined by HPV digital droplet (dd) PCR in tumor biopsies with previously known HPVDNA/p16 status from 270 OPSCC patients diagnosed 2000-2016 in Stockholm, Sweden. More specifically, of these patients 235 had HPVDNA/p16, 10 had HPVDNA/p16, 13 had HPVDNA/p16 and 12 had HPVDNA/p16 cancer.

Results: We found that HPVDNA/p16 OPSCC had a significantly higher viral load than HPVDNA/p16 OPSCC. Moreover, there was a tendency for a higher viral load in the tonsillar and base of tongue OPSCC subsites compared to the other subsites and for a low viral load to correlate to a better clinical outcome but none of these tendencies reached statistical significance.

Conclusion: To conclude, the mean viral load in HPVDNA/p16 OPSCC was higher than in HPVDNA/p16 OPSCC, but there was no statistically significant difference in viral load depending on OPSCC subsite or on clinical outcome.