Omitting elective neck irradiation in clinically N0 sinonasal adenoid cystic carcinoma: A propensity score-matched analysis

Abstract

Objective: To explore the effects of elective neck irradiation (ENI) in clinically node-negative (cN0) sinonasal adenoid cystic carcinoma (SNACC).

Materials and methods: Between January 2000 and December 2016, 60 patients with cN0 sinonasal adenoid cystic carcinoma receiving surgery combined with radiotherapy were analyzed retrospectively, there were 39 received ENI (ENI group) and 21 with no ENI (non-ENI group). Propensity score matching (PSM) was performed to balance clinical factors and match patients. Kaplan-Meier method and Cox proportional hazard model were used to evaluate the impact of ENI on regional relapse risk and survival outcomes.

Results: The median follow-up time for our cohort was 82.0 months (12.4-190.7 months). Four patients (6.7%) developed neck nodal relapses, with a median time to progression of 38.8 months. Among them, two patients in ENI group but failed out-field. After PSM, 21 patients were matched in each group. The 7-year regional relapse-free survival (RRFS), distant metastasis free survival (DMFS), progression-free survival (PFS), and overall survival (OS) between ENI group and non-ENI group were 85.4% vs 73.3% (p = 0.845), 65.2% vs 65.6% (p = 0.548), 68.3% vs 66.2% (p = 0.425), and 87.3% vs 84.0% (p = 0.953). Multivariate Cox analysis showed ENI was not an independent prognostic factor associated with RRFS, DMFS, PFS and OS.

Conclusion: Our findings firstly demonstrated the omission of elective neck irradiation in the management of cN0 sinonasal adenoid cystic carcinoma might be safe without compromising disease control and should be further investigated.

Keywords: Elective neck irradiation; Radiotherapy; Regional relapse; Sinonasal adenoid cystic carcinoma.