Oropharyngeal Squamous Cell Carcinoma With Discordant p16 and HPV mRNA Results: Incidence and Characterization in a Large, Contemporary United States Cohort.

Early studies estimate that 5% to 10% of oropharyngeal squamous cell carcinomas overexpress p16 but are unassociated with transcriptionally-active high-risk human papillomavirus (HPV). Patients with discordant HPV testing may experience clinical outcomes that differ from traditional expectations. To document the rate of p16 and HPV mRNA positivity, characterize patients with discordant testing, and identify features that may warrant selective use of HPV-specific testing after p16 IHC, a multi-institutional, retrospective review of oropharyngeal squamous cell carcinoma patients with p16 IHC and HPV mRNA testing by reverse transcriptase polymerase chain reaction was performed. Of the 467 patients, most had T1 or T2 tumors (71%), 82% were p16 positive, and 84% were HPV mRNA positive. Overall, most tumors were nonkeratinizing (378, 81%), which was strongly associated with p16 and HPV positivity (93% and 95%, respectively). Overall, 81% of patients were double positive, 14% double negative, and 4.9% discordant (3.4% p16 negative/HPV mRNA positive and 1.5% p16 positive/HPV mRNA negative). The survival rates of these discordant patient groups fell squarely between the 2 concordant groups, although in multivariate analysis for both disease-free survival and overall survival, discordant patients were not found to have statistically significantly different outcomes. Reclassifying patients by applying HPV mRNA testing when p16 results and morphology do not match, or when p16 results are equivocal, improved prognostication slightly over p16 or HPV mRNA testing alone. Patients with discordant testing demonstrate a borderline significant trend toward survival differences from those with concordant tests. When evaluated independently, patients who were p16 negative but HPV mRNA positive had a prognosis somewhat closer to double-positive patients, while those who were p16 positive, but HPV mRNA negative had a prognosis closer to that of double-negative patients. We suggest an algorithm whereby confirmatory HPV mRNA testing is performed in patients where p16 status is not consistent with tumor morphology. This captures a majority of discordant patients and improves, albeit modestly, the prognostication.

The Natural History of Oral Human Papillomavirus in Young Costa Rican Women.

BACKGROUND: Oral human papillomavirus (HPV) infection and related oropharyngeal cancer are uncommon in lower-income countries, particularly compared to HPV-associated cervical cancer. However, little is known about the natural history of oral HPV in less-developed settings and how it compares to the natural history of cervical HPV. METHODS: Three hundred fifty women aged 22 to 33 years from the Costa Rica Vaccine Trial provided exfoliated cells from the cervical and oral regions at 2 visits 2 years apart. Samples from both visits were tested for 25 characterized α HPV types by the SPF10 PCR-DNA enzyme immunoassay-LiPA25 version 1 system. Risk factors for oral HPV persistence were calculated utilizing generalized estimating equations with a logistic link. RESULTS: Among the 82 women with characterized α oral HPV DNA detected at baseline, 14 persisted and were detected 2 years later (17.6%; 95% confidence interval [CI], 10.9-28.5%) and was similar to the persistence of α cervical HPV (40/223; 17.7%; 95% CI, 13.1-23.9%; P = 0.86). Acquisition of new α oral HPV type was low; incident infection (1.7%; 95% CI, 0.6-3.7%). CONCLUSIONS: Oral HPV DNA is uncommon in young women in Latin America, and often appears to clear within a few years at similar rates to cervical HPV.

Reduced prevalence of vulvar HPV16/18 infection among women who received the HPV16/18 bivalent vaccine: a nested analysis within the Costa Rica Vaccine Trial.

BACKGROUND: Vaccine efficacy (VE) against vulvar human papillomavirus (HPV) infection has not been reported and data regarding its epidemiology are sparse. METHODS: Women (n = 5404) age 22-29 present at the 4-year study visit of the Costa Rica Vaccine Trial provided vulvar and cervical samples. A subset (n = 1044) was tested for HPV DNA (SPF10/LiPA25 version 1). VE against 1-time detection of vulvar HPV16/18 among HPV vaccinated versus unvaccinated women was calculated and compared to the cervix. Prevalence of and risk factors for HPV were evaluated in the control arm (n = 536). RESULTS: Vulvar HPV16/18 VE (54.1%; 95% confidence interval [CI], 4.9%-79.1%) was comparable to cervix (45.8%; 95% CI, 6.4%-69.4%). Vulvar and cervical HPV16 prevalence within the control arm was 3.0% and 4.7%, respectively. Independent risk factors for vulvar HPV were similar to cervix and included: age (adjusted odds ratio [aOR] 0.5 [95% CI, .3-.9] ≥28 vs 22-23]); marital status (aOR 2.3 [95% CI, 1.5-3.5] single vs married/living-as-married); and number of sexual partners (aOR 3.6 [95% CI, 1.9-7.0] ≥6 vs 1). CONCLUSIONS: In this intention-to-treat analysis, VE against vulvar and cervical HPV16/18 were comparable 4 years following vaccination. Risk factors for HPV were similar by anatomic site. CLINICAL TRIALS REGISTRATION: NCT00128661.

Prevalence of and risk factors for oral human papillomavirus among young women in Costa Rica.

BACKGROUND: Little is known about the epidemiology of oral human papillomavirus (HPV) in Latin America. METHODS: Women (N = 5838) aged 22-29 in the control and vaccine arms of an HPV-16/18 vaccine trial in Costa Rica had oral, cervical, and anal specimens collected. Samples were tested for alpha mucosal HPV types (SPF10/LiPA25 version 1); a subset of oral samples (n = 500) was tested for cutaneous HPV types in the genera alpha, beta, gamma, mu, and nu. RESULTS: In the control arm (n = 2926), 1.9% of women had an oral alpha mucosal HPV detected, 1.3% had carcinogenic HPV, and 0.4% had HPV-16; similar patterns for non-16/18 HPV types were observed in the vaccine arm. Independent risk factors for any oral alpha mucosal HPV among women in the control arm included marital status (adjusted odds ratio [AOR], 3.2; 95% confidence interval [CI], 1.8-5.7 for single compared to married/living as married), number of sexual partners (AOR, 2.4; 95% CI, 1.0-6.1 for ≥4 partners compared to 0-1 partners), chronic sinusitis (AOR, 3.1; 95% CI, 1.5-6.7), and cervical HPV infection (AOR, 2.6; 95% CI, 1.4-4.6). Detection of beta HPV was common (18.6%) and not associated with sexual activity. CONCLUSIONS: Unlike cutaneous HPV types, alpha mucosal HPV types were uncommon in the oral region and were predominately associated with sexual behavior. Clinical Trials Registration. NCT00128661.