New Staging for HPV-Positive Oropharygeal Cancer

http://jco.ascopubs.org/content/early/2016/02/11/JCO.2015.64.6448.full

New Staging System for HPV-Positive Oropharyngeal Cancer

Veronica Hackethal, MD

February 24, 2016 Researchers at the University of Texas MD Anderson Cancer Center, in Houston, have shown that the current staging system for human papilloma virus (HPV)–positive oropharyngeal cancer is not adequate.
They have proposed a new staging system for these cancers, and they have reported results that show that the new system may allow physicians to better predict survival and plan treatment accordingly.
Their research was published online January 16 in the Journal of Clinical Oncology.
The new system has two key components, according to lead author Erich M. Sturgis, MD, professor in the Department of Head and Neck Surgery, University of Texas MD Anderson Cancer Center.
First, it uses a statistical technique called recursive patterning analysis that combines the T and N categories from the T (tumor) N (node) M (metastasis) staging system to yield overall staging categories. Second, it uses N categories derived from the nasopharyngeal cancer staging system. Nasopharyngeal cancer is virally induced by Epstein-Barr virus, and its natural history may be similar to that of HPV-positive oropharyngeal cancer, the authors comment.
The study is the first to apply the N category from nasopharyngeal cancer to cancer staging in HPV-positive oropharyngeal cancer, they note.
"When we used the N category from the nasopharyngeal cancer staging system and combined the T and N categories, it stratified patients much better as far as survival outcomes, and patients were distributed across the four stages much more evenly," Dr Sturgis said.
At present, the American Joint Commission on Cancer/Union for International Cancer Control oropharyngeal cancer staging system is used to stage both HPV-positive and HPV-negative oropharyngeal cancer, even though it was derived from tobacco-related HPV-negative oropharyngeal cancer. Although other groups have shown that the current staging system works very well for patients with HPV- negative oropharyngeal cancer, it does not differentiate patients with HPV-positive cancer well in terms of prognosis. In addition, it classifies virtually all patients as having stage IV disease, Dr Sturgis explained.

 

HPV-positive oropharynx cancer is becoming an epidemic. It's dominating what we're seeing in the head and neck clinics. Dr Erich Sturgis

 

"The current staging system does not work for many oropharynx cancers because now most of these cancers are HPV-related," he stressed. "HPV-positive oropharynx cancer is becoming an epidemic. It's dominating what we're seeing in the head and neck clinics, and we desperately need a staging system for these cancers."
Study Details
The study analyzed 661 patients with HPV-positive oropharyngeal cancer who received care at the MD Anderson Cancer Center between January 2003 and December 2012.
Using the current staging system, results showed no significant difference in overall survival (P = .141) and an unbalanced distribution of patients across stages, with 82% of patients categorized as having stage IV disease. The T category was the most important predictor of survival, whereas the N category was nonsignificant.
After replacing the old N category with the one from the nasopharyngeal cancer staging system, the N category became a significant predictor of overall and progression-free survival across stages (P < .001 for both). The risk for death also increased with higher stages (P for trend < .001). The T category, however, remained most important.
On the basis of these findings, the researchers proposed the following system:

• Stage IA: T1, N0-N2
  
• Stage IB: T2, N0-N2
  
• Stage II: T1-T2, N3 or T3, N0-N3
  
• Stage III: T4, regardless of nodal involvement
  
• Stage IV: All M1 tumors
  

Further analyses suggested that use of the new system would result in more evenly balanced groups compared with the current system. The new system also differentiated groups better in terms of overall and progression-free survival. Results showed that patients with stage III disease had five times greater risk for death compared with those with stage IA disease (hazard ratio, 5.0; 95% confidence interval, 2.0 - 12.2).
"The real key shift is that patients who have involvement of the supraclavicular fossa are a higher N category than in the previous staging system," Dr Sturgis pointed out. "The other key shift is that if lymph node metastases are not low in the neck but are bilateral in nature, then it's N category 2."
The new system may allow physicians to better identify patients who have worse prognoses and who may benefit from more aggressive therapy. It may also lead to less overtreating of those who need only the standard treatment.
Because this was a single-center study, results may differ at other institutions, Dr Sturgis emphasized, and the new staging system needs validation in other settings.
He concluded, "We would advocate keeping the current staging system for HPV-unrelated OPC [oropharyngeal cancer] and that this would be the new staging system for HPV-related OPC."
The authors have disclosed no relevant financial relationships.
J Clin Oncol. Published online February 16, 2016. Full text

 

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Cite this article: New Staging System for HPV-Positive Oropharyngeal Cancer. Medscape. Feb 24, 2016.