• We assessed the value of rENE and the efficacy of chemotherapy in stage T1-2 N1 NPC. • Unequivocal rENE is an independent adverse prognostic factor for T1-2 N1 NPC. • Addition of chemotherapy did not affect prognosis in T1-2 N1 patients without rENE. • T1-2 N1 patients with rENE may benefit from higher doses of chemotherapy. This multicenter retrospective study aimed to investigated the prognostic value of unequivocal radiologic extranodal extension (rENE) and the efficacy of chemotherapy for stage T1-2 N1 nasopharyngeal carcinoma (NPC) in the IMRT era. We included 1,082 patients treated in 2005–2017 from three centers. rENE was recorded as G1 (coalescent nodal mass comprising ≥ 2 inseparable nodes) or G2 (invading beyond perinodal fat to frankly infiltrate adjacent structures). Multivariable analysis (MVA) evaluated the prognostic value of rENE. The value of chemotherapy was assessed in rENE-positive (rENE +) and rENE-negative (rENE −) subset separately. Centers 1, 2, and 3 had 139/515 (27.0 %), 100/365 (27.4 %), and 43/202 (21.3 %) cN + patients with rENE, respectively. Compared to rENE−, rENE + patients had a worse distant metastasis-free survival (DMFS) and overall survival (OS) (all p < 0.001). MVA confirmed the prognostic of both G1-rENE and G2-rENE for distant metastasis [G1: hazard ratio (HR): 2.933, G2: HR: 6.942, all p < 0.001] and death (G1: HR: 1.587, p = 0.040; G2: HR: 6.162, p < 0.001). There was no significant difference for DMFS and OS between chemo-radiotherapy and radiotherapy alone in rENE + and rENE − groups (all p > 0.1). However, rENE + patients with a cumulative cisplatin/nedaplatin dose (CCND) of > 160 mg/m2 had an improved DMFS (p = 0.033) but no OS (p = 0.197). Unequivocal rENE is prognostic in patients with T1-2 N1 NPC. Addition of chemotherapy to radiotherapy did not affect DMFS and OS in rENE − patients. Chemotherapy with a CCND of > 160 mg/m2 improved DMFS in rENE + patients. [ABSTRACT FROM AUTHOR]