Zhenzhen Yin 

Radiation, Cancer Institute (Hospital), Chinese Academy of Medical Sciences, Peking union     Medical College.

Objective:Esthesioneuroblastoma (ENB) is a rare malignant neoplasm with great controversies on management of the neck. The aim of this study is to characterize the incidence and regional lymphatic spread patterns of N+ disease, assess the role of elective neck irradiation (ENI) in patients with N0 disease, and explore the reasonable neck treatment target. 

Method:This is a retrospective analysis of 116 patients with treated naïve ENB in our institution between Jun. 1979 and Jun. 2014. According to Kadish classification, the distribution was 1% (1 patient) in stage A, 20% (23 patients) stage B, 79% (92 patients) stage C. 32 patients showed cervical lymph node metastasis in initial staging (including 4 patients with distant organ metastasis simultaneously). Among 84 patients with N0 disease, the managements of neck in 80 patients with Kadish B/C were available, treatment modalities consisted of primary RT in 27 patients, preoperative RT in 10 patients, postoperative RT in 40 patients, surgery alone in 3 patients. 50 patients were delivered with ENI and 30 patients without any prophylactic neck treatment. 

Result:32/116 (28%) patients were identified as N-positive in initial diagnosis. The common sites were level II (81%), IB (53%), level III (28%) and retropharyngeal nodes (22%). The 5-year regional failure-free survival rate was 98% in N-negative patients treated with ENI and 75% in patients without ENI (P=0.005), 5-year disease-free survival rate was 71% and 50% (P=0.178), 5-year overall survival rate was 77% and 62% (P=0.424). Regional failure occurred in 1 of 50 (2%) patients treated with ENI, while in 7 of 30 (23%) patients without ENI (P=0.002). Neck occurrences most developed on level Ib and II. Multivariate analysis suggested ENI was an independent predictor for regional control (HR, 0.093; 95% CI: 0.011-0.756; P=0.026). 

Conclusion:ENB presented predictable patterns of cervical node metastases. Prophylactic elective neck irradiation reduced the regional failure significantly, should be recommended as a part of initial treatment strategy for N-negative patients in advanced disease. The treatment target of ENI should at least encompass the bilateral level IB-III and RPNs.

Key Words: Esthesioneuroblastoma, Lymphatic spreading, Elective