Prospective Long-term Patient-Reported Quality of Life Outcomes Following Intensity Modulated Radiation Therapy in Head and Neck Cancer

Abstract

Materials/Methods: Twenty-three patients without prior head and neck cancers or metastatic disease who were treated with PT to 70.0 Gy (RBE) (range, 61.2-74.4 Gy [RBE]) for major and minor salivary gland cancers were enrolled on an IRB-approved outcomes tracking protocol between 2006 and 2014. Twenty-one patients received postoperative PT and 2 received primary PT for unresectable disease. Gross residual disease was present in 7 patients at the time of PT. Five patients also received intensity modulated radiation therapy (median dose, 18 Gy; range, 16.2-50.4 Gy). Median follow-up was 2.5 years (range, 0.6-7.6 years). Grade 3 or higher toxicity was reported using the Common Terminology Criteria for Adverse Events, version 4. Results: The 3-year overall survival and disease-free survival rates were 81% and 73%, respectively. The 3-year local control, regional/neck control, and freedom from metastasis rates were 87%, 91%, and 81%, respectively. Gross residual disease was a major prognostic factor. The 3year local control, overall survival, and disease-free survival rates were 57%, 57%, and 29% for the 7 patients with gross disease, while for the remaining 16 patients who did not have gross disease at the time of PT, the 3-year local control, overall survival, and disease-free survival rates were 100% (PZ.0045), 92% (PZ.0136), and 94% (PZ.0003), respectively. Grade 3 toxicities occurred in 4 (17%) patients and included hearing loss, otitis externa with mastoiditis, double vision limiting activities of daily living, and a seizure secondary to radionecrosis. Median time after PT to grade 3 toxicity was 23 months. There were no grade 4 or 5 events. Conclusion: Proton therapy is an effective primary and postoperative therapy for salivary gland cancers. Nearly all patients who undergo gross total resection and proton therapy were cured. Unexpected serious toxicities were rare. The presence of gross disease at the time of proton therapy was the major negative prognostic factor. These patients are in need of innovative treatment strategies. Author Disclosure: T.L. Smith: None. C.M. Bryant: None. J.A. Bradley: None. D.J. Indelicato: None. C.G. Morris: None. R. Dagan: None.