Long-term survival after distant metastasis in patients with oropharyngeal cancer

Objectives: For patients with oropharyngeal squamous cell carcinoma (OPSCC), especially for those with HPV-positive tumors, locoregional control is excellent. Distant metastasis, however, remains a substantial problem. The purpose of our study was to evaluate outcomes and predictors of survival after distant metastasis in OPSCC.

Materials and methods: Between June 2002 and January 2011, 25 OPSCC patients treated with curative intent subsequently developed distant metastasis. The primary end-points evaluated were time-to-distant metastasis and overall survival after development of distant metastasis. Predictors of outcome were evaluated with median regression analysis or Cox regression. Best subset models were chosen to minimize the Bayesian Information Criterion (BIC). A prognostic index for survival after distant failure was created based on the selected model.

Results: Median time-to-distant metastasis after completion of radiation was 7.9 months (range, 1.6-25.4). Median overall survival from distant metastasis was 18.3 months (95% CI, 14.3-39.8). The overall survival rates at 1- and 2-year after development of distant metastasis were 72.0% (95% confidence interval [CI], 53.4-89.6) and 40.8% (95% CI, 20.6-61.0), respectively. In multivariate analysis, Karnofsky Performance Status score (KPS) > or = 80 (p=0.01, hazard ratio [HR] 0.15, 95% CI, 0.04-0.52) and limited, single-organ disease (p=0.003, HR 0.13, 95% CI 0.03-0.61) predicted for increased survival from distant metastasis. Patients with both limited disease and good KPS formed the most favorable risk group with a 2-year survival of 100%. Two patients with human papilloma virus (HPV)-positive tumors were alive without any evidence of disease at 64.6 and 60.4 months, respectively, after aggressive local treatment of solitary metastasis.

Conclusion: For OPSCC patients with limited, single-organ disease and good KPS, long-term survival can be achieved.