HPV-positive patients had a two-year overall survival of 88% compared with 66% for HPV-negative patients (P<0.001), said Maura Gillison, M.D., of Ohio State University in Columbus.
The difference between groups increased with follow-up. HPV infection also was associated with a reduced risk of locoregional recurrence and second cancers, Dr. Gillison reported at a press briefing in advance of the American Society of Clinical Oncology annual meeting.
Cancer of the oropharynx arises from two principal causes: chronic use of tobacco and alcohol or HPV infection. Previous studies had suggested that HPV status of a patient’s tumor might have prognostic implications.
“HPV-positive patients have important associations with other favorable prognostic factors,” said Dr. Gillison. “They tend to be younger; they have smaller tumors; they present with better performance status. Therefore, improvement in survival for this patient population may be explained by these factors and not by HPV.”
To explore the role of HPV status in survival of oropharyngeal cancer, Dr. Gillison and colleagues reviewed data from a randomized clinical trial conducted by the Radiation Therapy Oncology Group.
Its principal objective was to compare standard chemotherapy with an investigational regimen.
The trial involved 721 patients. Of those, 60% had cancer of the oropharynx and 64% were HPV positive.
The two-year results demonstrated a clear survival advantage associated with HPV infection. Follow-up to five years revealed an overall survival of >75% in HPV-positive patients versus <50% in HPV-negative patients.
The difference remained largely unchanged in an analysis that accounted for other factors, including treatment assignment.
“HPV-positive patients had less than half the risk of dying from their cancer at five years than HPV-negative patients, after considering the effects of other important factors,” said Dr. Gillison.
“HPV-positive patients similarly had about half the risk of tumor progression or death, due in part to lower recurrence rates in the radiation field but not lower distant metastases.”
As a result of the findings, RTOG and the Eastern Cooperative Oncology Group will begin to stratify all clinical trials by HPV status and possibly design trials specifically for HPV-positive or negative patients, she added.
| Dr. Gillison reported no competing interests. |
Source reference:
Gillison ML, et al “Human papillomavirus and survival of patients with oropharynx cancer”ASCO 2009.
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