Phase 2 bioadjuvant study of interferon alfa-2a, isotretinoin, and vitamin E in locally advanced squamous cell carcinoma of the head and neck: long-term follow-up

Abstract

Objective: To evaluate the long-term effects of the combination of isotretinoin, interferon alfa-2a, and vitamin E in locally advanced squamous cell carcinoma of the head and neck.

Design: Phase 2 prospective study.

Setting: Tertiary care academic medical centers.

Patients: Forty-five patients entered this study. All patients had stage III or IV squamous cell carcinoma of the head and neck and had been treated with surgical resection, radiation, or both. All patients were then treated with bioadjuvant chemopreventive treatment for 12 months. We previously reported a 24-month median follow-up of this phase 2 trial of the combination of isotretinoin, interferon alfa-2a, and vitamin E as bioadjuvant therapy after definitive local therapy. In that study, all 45 patients completed treatment, but 1 patient was excluded from analysis of recurrence and development of second primary tumors. Main Outcome Measure Longer-term (49.4-month median) follow-up.

Results: Among the 45 patients treated under the protocol, only 7 patients (16%) had died. Nine (20%) of 45 patients experienced progressive disease. Only 1 second primary tumor (acute promyelocytic leukemia) occurred during follow-up, and no aerodigestive second primary tumors occurred among the 45 patients. The 5-year progression-free survival and overall survival percentages were 80% (95% confidence interval, 65.1%-89.1%) and 81.3% (95% confidence interval, 63.7%-90.9%), respectively. These results are significantly better than the historical 5-year overall survival for advanced squamous cell carcinoma of the head and neck (approximately 40%).

Conclusion: The bioadjuvant combination is highly effective in preventing recurrence and second primary tumors, and its role as standard therapy in advanced squamous cell carcinoma of the head and neck is being investigated in a randomized phase 3 study.