Relationships between epidermal growth factor receptor expression and human papillomavirus status as markers of prognosis in oropharyngeal cancer.

PURPOSE

This study examines the prognostic significance of epidermal growth factor receptor (EGFR) expression in relation to human papillomavirus (HPV) status in oropharyngeal squamous cell carcinoma (SCC).

MATERIALS AND METHODS

Pathological diagnosis of 270 oropharyngeal SCCs was verified by the study pathologist; clinical details were extracted from institutional databases. Recurrence in any form or death from any cause was recorded for a median of 2.5 (range: 0-19.3) years after diagnosis. HPV status was determined by HPV E6-targeted multiplex real-time PCR/p16 immunohistochemistry; EGFR expression was evaluated by semiquantitative immunohistochemistry. Determinants of recurrence and mortality hazards were modelled using Cox regression with censoring at dates of last follow-up.

RESULTS

Thirty-seven percent of cancers were HPV-positive (91% type 16). HPV was a predictor of loco-regional recurrence, event-free and overall survival after adjustment for clinicopathological variables and EGFR. Patients with EGFR-positive cancers were 5-fold more likely to have loco-regional failure relative to those with EGFR-negative cancers. Patients with HPV-negative/EGFR-positive cancers had an adjusted 13-fold increased risk of having a loco-regional failure, an almost 4-fold increased risk of having an event and more than a 4-fold increased risk of dying of any cause relative to those with HPV-positive/EGFR-negative cancers. There was weak evidence that the effects of EGFR on outcome were limited to patients with HPV-negative cancers.

CONCLUSIONS

HPV and EGFR are independent prognostic markers in oropharyngeal SCC. Combining testing for HPV and EGFR appears to provide additional prognostic information.