Lymph node metastasis in sinonasal squamous cell carcinoma treated with IMRT/3D-CRT

Abstract

To analyze the patterns of neck and retropharyngeal lymph nodes (RPLNs) metastases with magnetic resonance imaging (MRI) in patients with sinonasal squamous cell carcinoma (SCC), and to explore the patterns of treatment failure treated with intensity modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3D-CRT). We also attempt to discuss the role of elective neck irradiation (ENI) in the treatment of cervical negative patients. Between July 2004 and February 2011, 59 patients with histopathologically proven sinonasal SCC were treated with curative intent at our hospital. Among them, 18 (30.5%) patients had neck or RPLN lymph node involvement at diagnosis. RPLN, level Ib, and level IIa were the most common sites of initial nodal involvement. All patients received IMRT or 3D-CRT, while 19 patients further received surgical resection, and other 40 patients received cisplatin based chemotherapy. Median follow-up durations were 28 months (range, 6-81 months) for the entire patient population and 40 months (range, 7-81 months) among the surviving patients, respectively. The estimated 3-year local-regional control rate, distant-metastasis free survival rate, disease-free survival rate, and overall survival rate were 63.3%, 81.9%, 60.1%, and 68.9%, respectively. On multivariate analysis, old age (>60 years) significantly influenced the overall survival rate(HR=9.428, p=0.000). As for the pattern of treatment failures developed in 26 patients in the follow-up time, local failure, neck recurrence, and distant metastases were seen in 18, 7, and 9 patients, respectively. Level Ib and level IIa were the most common sites of cervical nodal recurrence. None of the 11 patients who received ENI developed failure in the neck. For sinonasal SCC patients treated with IMRT or 3D-CRT, our results were generally consistent with findings of other studies, local failure still remain the predominant pattern of treatment failure. However, RPLN metastasis occurred more frequently than previously recognized through detection by MRI in our study. ENI seems to have effectively prevented regional relapse. We recommend ipsilateral level Ib and level IIa neck irradiation for T3-4 sinonasal SCC patients.