Extracapsular extension is associated with worse distant control and progression-free survival in patients with lymph node-positive human papillomavirus-related oropharyngeal carcinoma.

OBJECTIVES

To determine the prognostic utility of pathologic extracapsular extension (ECE) in human papillomavirus (HPV) associated oropharyngeal squamous cell carcinoma (OPSCC).

MATERIALS AND METHODS

Retrospective analysis was performed on patients who underwent surgery for primary HPV-related OPSCC and received adjuvant radiotherapy (RT) between 2006 and 2015. Locoregional control (LRC), distant control (DC), progression-free survival (PFS) and overall survival (OS) were compared between the groups with and without ECE using univariate Kaplan-Meier and multivariate Cox regression survival analyses.

RESULTS

75 patients were identified and ECE was demonstrated on the surgical pathology of 26 patients. ECE(+) patients more frequently received chemotherapy (76.9% vs. 32.7%; p<0.0001) and RT doses>66Gy (76.9% vs. 16.3%; p<0.001). With a median follow-up of 29months, patients with ECE had a significantly worse 5-year DC rate than those without ECE (76.7% vs. 97.9%; p=0.046), and patients with ECE had a significantly worse 5-year PFS (54.5% vs. 93.6%; p=0.021) than those without ECE. On multivariate Cox regression analysis, ECE was independently prognostic of worse DC (hazard ratio: 8.26; 95% confidence interval: 1.24-55.21; p=0.029) and worse PFS(HR: 4.64; 95% CI: 1.18-18.29; p=0.028). There was no statistically significant difference in 5-year LRC (93.3% vs. 95.7%) or OS (66.9% vs. 97.0%) between ECE(+) and ECE(-) patients, respectively.

CONCLUSION

This study suggests that ECE is independently prognostic of worse DC and PFS in patients who undergo surgery prior to adjuvant RT for primary HPV-related OPSCC.