A new staging system for oropharyngeal carcinoma—one that more accurately predicts outcomes for patients with human papillomavirus (HPV)–related disease—has been proposed by researchers at The University of Texas MD Anderson Cancer Center.
Although HPV status is a strong prognostic factor in patients with oropharyngeal carcinoma, the current TNM guidelines for cancer staging (AJCC Cancer Staging Manual, seventh edition) do not adequately account for biological and clinical differences between HPV-positive and HPV-negative oropharyngeal carcinoma.
The researchers evaluated the prognostic value of the current staging system by reviewing the records of 661 patients with HPV-positive oropharyngeal carcinoma treated at MD Anderson from January 2003 through December 2012 and found no differences in overall survival among groups of patients stratified by disease stage.
Next, the researchers analyzed the current TNM categories individually as predictive factors for survival in the same patient population. The T category was the strongest predictive factor, whereas the N category appeared to have no predictive value.
Whereas the current N category criteria for oropharyngeal carcinoma are similar to those for head and neck cancers that are not associated with a viral infection, the N category criteria for nasopharyngeal carcinoma—which is associated with Epstein-Barr virus infection—include not only the number and laterality of positive lymph nodes but also whether supraclavicular nodes are involved. The researchers therefore adapted the N category criteria for nasopharyngeal carcinoma and repeated their analysis.
With the revised criteria, the N category became a significant predictor of survival. On the basis of their findings, the researchers developed a new staging system for HPV-positive oropharyngeal carcinoma that combined the current oropharyngeal carcinoma T category and nasopharyngeal carcinoma N category criteria. When the new system was applied to the cohort of 661 patients with HPV-positive oropharyngeal cancer, the risk of death increased with each disease stage.
“The revised staging system has greater predictive power than the current system, which has been shown to be insufficient for HPV-positive oropharyngeal carcinoma,” said Erich Sturgis, M.D., a professor in the Department of Head and Neck Surgery and the corresponding author of the study’s report, which was published in February in the Journal of Clinical Oncology. However, Dr. Sturgis added that the study’s findings need to be confirmed in cohorts of patients treated elsewhere.
OncoLog, May 2016, Volume 61, Issue 5