A B S T R A C T PurposeRecent increases in incidence and survival of oropharyngeal cancers in the United States have been attributed to human papillomavirus (HPV) infection, but empirical evidence is lacking.
Patients and MethodsHPV status was determined for all 271 oropharyngeal cancers collected by the three population-based cancer registries in the Surveillance, Epidemiology, and End Results (SEER) Residual Tissue Repositories Program by using polymerase chain reaction and genotyping (Inno-LiPA), HPV16 viral load, and HPV16 mRNA expression. Trends in HPV prevalence across four calendar periods were estimated by using logistic regression. Observed HPV prevalence was reweighted to all oropharyngeal cancers within the cancer registries to account for nonrandom selection and to calculate incidence trends. Survival of HPV-positive and HPV-negative patients was compared by using Kaplan-Meier and multivariable Cox regression analyses.
ResultsHPV prevalence in oropharyngeal cancers significantly increased over calendar time regardless of HPV detection assay (P trend Ͻ .05). For example, HPV prevalence by Inno-LiPA increased from 16.3% during 1984 to 1989 to 71.7% during 2000 to 2004. Median survival was significantly longer for HPV-positive than for HPV-negative patients (131 v 20 months; log-rank P Ͻ .001; adjusted hazard ratio, 0.31; 95% CI, 0.21 to 0.46). Survival significantly increased across calendar periods for HPV-positive (P ϭ .003) but not for HPV-negative patients (P ϭ .18). Population-level incidence of HPV-positive oropharyngeal cancers increased by 225% (95% CI, 208% to 242%) from 1988 to 2004 (from 0.8 per 100,000 to 2.6 per 100,000), and incidence for HPV-negative cancers declined by 50% (95% CI, 47% to 53%; from 2.0 per 100,000 to 1.0 per 100,000). If recent incidence trends continue, the annual number of HPV-positive oropharyngeal cancers is expected to surpass the annual number of cervical cancers by the year 2020.
ConclusionIncreases in the population-level incidence and survival of oropharyngeal cancers in the United States since 1984 are caused by HPV infection.
Background
Patients with HPV-positive oropharyngeal squamous cell carcinoma (OPC) have high survival rates when treated with radiotherapy plus cisplatin. Whether replacement of cisplatin with cetuximab, an antibody against the epidermal growth factor receptor, can preserve high survival rates and reduce treatment toxicity is unknown.
Methods
In a randomized, non-inferiority, multicenter trial, patients with locoregionally-advanced p16-positive OPC were stratified by American Joint Committee on Cancer T (T1-T2 vs. T3-T4) and N (N0-N2a vs. N2b-N3), Zubrod Performance Status (0 vs. 1), and tobacco smoking history (≤ vs. >10 pack-years) and randomized 1:1 to radiotherapy plus cetuximab 400 milligrams per square meter of body surface area (mg/m2), followed by 250 mgs/m2 for seven weekly doses or cisplatin 100 mgs/m2 for two doses, 21 days apart. The sample size was 800 eligible patients. The primary endpoint was overall survival (OS) with non-inferiority margin 1.45 (hazard ratio).
Findings
From June 2011 through July 2014, 849 patients (805 eligible; 399 cetuximab; 406 cisplatin) were randomized at 182 centers in the United States and Canada. With median follow-up 4·5 years, radiotherapy plus cetuximab did not meet the non-inferiority criterion for OS. Estimated 5-year OS was 77·9% (95% confidence interval [CI] 73·4-82·5) in cetuximab group versus 84·6% (95%CI=80·6-88·6) in cisplatin group (hazard ratio [HR], 1·45, 1-sided 95% upper CI, 1·94; non-inferiority p=0·5056; 1-sided log-rank p=0.0163). PFS was significantly lower in cetuximab group than in cisplatin group (HR 1·72, 95%CI=1·29-2·29; 5-year rates, 67·3% vs. 78·4%), and LRF was significantly higher (HR 2·05, 95%CI=1·35-3·10; 5-year rates, 17·3% vs. 9·9%). The rate of moderate-to-severe toxicity that was acute (77·4% vs. 81·7%, p=0·1586) and late (16·5 vs. 20·4%, p=0·1904) was similar in the cetuximab and cisplatin groups, respectively.
Interpretation
For patients with HPV-positive OPC, radiotherapy plus cetuximab demonstrated inferior OS and PFS compared to radiotherapy plus cisplatin; toxicity rates were similar (NCT01302834).
Funding
National Cancer Institute USA, Eli Lilly and The Oral Cancer Foundation
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