Change in patterns of relapse after combined proton and photon irradiation for locally advanced paranasal sinus cancer

Abstract

To evaluate the outcome and patterns of failure of patients with locally advanced paranasal sinus cancer treated with combined proton and photon radiotherapy. Between 1988 and 2002, 91 patients with newly diagnosed non-metastatic American Joint Committee on Cancer (AJCC) stage III - IV paranasal sinus cancer received combined conformal proton and photon radiotherapy at the Massachusetts General Hospital. There were 43 females and 48 males, with a median age of 51 years (range 16 - 82). The histology was squamous cell carcinoma in 28, carcinoma with neuroendocrine differentiation in 34, adenoid cystic carcinoma in 20, and sarcoma in 9 patients. Sixty-seven percent of patients underwent surgical resection before radiation. The median total prescribed dose to the primary target volume was 73.6 Cobalt-Gray-Equivalent (CGE) (range 59.40–77.80). The median proportion of proton dose was 49% (range 23 - 84). Eighty-seven percent of patients received continuous accelerated hyperfractionated radiotherapy. Thirty-two patients received chemotherapy, and 84% of these received cisplatin and etoposide for carcinoma with neuroendocrine differentiation. The mean follow-up of patients in the study was 3.8 years. With a mean follow-up of 45 months, 11, 6, and 19 patients developed local recurrence, neck recurrence, and distant metastasis, respectively, as their first site of failure. Distant metastasis was the predominant pattern of relapse for squamous cell carcinoma, carcinoma with neuroendocrine differentiation, and adenoid cystic carcinoma. At 3 and 5 years, overall survival rates were 65% and 58%, respectively. The disease-free survival rates at 3 and 5 years were 59% and 52%, respectively. The overall freedom from distant metastatic rates at 3 and 5 years were 79% and 75%, respectively. The 3- and 5-year actuarial local control rates were 87% and 82%, respectively. The local control rate at 3 years was 83% for squamous cell carcinoma, 91% for carcinoma with neuroendocrine differentiation, 86% for adenoid cystic carcinoma, and 88% for sarcoma (figure 1). The ultimate local control rate after salvage treatment was 89% and 86% at 3 and 5 years, respectively. The neck control rate was 91% and 89% at 3 and 5 years, respectively. Combined proton and photon irradiation results in improved local control for patients with locally advanced paranasal sinus cancer. Distant metastasis is the predominant pattern of failure.