Oropharyngeal squamous-cell carcinomas caused by human papillomavirus (HPV) are associated
with favorable survival, but the independent prognostic significance of tumor HPV
status remains unknown.
We performed a retrospective analysis of the association between tumor HPV status
and survival among patients with stage III or IV oropharyngeal squamous-cell carcinoma
who were enrolled in a randomized trial comparing accelerated-fractionation radiotherapy
(with acceleration by means of concomitant boost radiotherapy) with standard-fractionation
radiotherapy, each combined with cisplatin therapy, in patients with squamous-cell
carcinoma of the head and neck. Proportional-hazards models were used to compare the
risk of death among patients with HPV-positive cancer and those with HPV-negative
cancer.
The median follow-up period was 4.8 years. The 3-year rate of overall survival was
similar in the group receiving accelerated-fractionation radiotherapy and the group
receiving standard-fractionation radiotherapy (70.3% vs. 64.3%; P=0.18; hazard ratio
for death with accelerated-fractionation radiotherapy, 0.90; 95% confidence interval
[CI], 0.72 to 1.13), as were the rates of high-grade acute and late toxic events.
A total of 63.8% of patients with oropharyngeal cancer (206 of 323) had HPV-positive
tumors; these patients had better 3-year rates of overall survival (82.4%, vs. 57.1%
among patients with HPV-negative tumors; P<0.001 by the log-rank test) and, after
adjustment for age, race, tumor and nodal stage, tobacco exposure, and treatment assignment,
had a 58% reduction in the risk of death (hazard ratio, 0.42; 95% CI, 0.27 to 0.66).
The risk of death significantly increased with each additional pack-year of tobacco
smoking. Using recursive-partitioning analysis, we classified our patients as having
a low, intermediate, or high risk of death on the basis of four factors: HPV status,
pack-years of tobacco smoking, tumor stage, and nodal stage.
Tumor HPV status is a strong and independent prognostic factor for survival among
patients with oropharyngeal cancer. (ClinicalTrials.gov number, NCT00047008.)
2010 Massachusetts Medical Society