The prognostic value of image-identified extranodal extension in laryngeal and hypopharyngeal carcinoma following definitive (chemo-)radiotherapy

Abstract

ObjectivesClinical extranodal extension (cENE) is a cN modifier in TNM-8 for laryngo-hypopharygeal carcinoma (LHC). We hypothesize that image-detected ENE (iENE) can provide additional prognostic value over cENE in LHC. MethodsBaseline CTs/MRIs of cN+ LHC patients treated with definitive (chemo-)radiotherapy between 2010–2019 were re-reviewed by a neuroradiologist using internationally accepted criteria for iENE-positive/negative (iENE+/iENE–). Overall survival (OS) was compared by iENE status. Multivariable analysis (MVA) was performed to confirm the prognostic value of iENE, adjusted for known potential confounders. ResultsA total of 232 LHC patients were identified, including 154 iENE–/cENE–, 60 iENE+/cENE–, and 18 iENE+/cENE+. A higher proportion of iENE+ (vs iENE–) patients had lymph node (LN) size > 3 cm [53 (67 %) vs 4 (3 %)], >=5 LNs [51 (65 %) vs 33 (21 %)], and retropharyngeal LN [12 (15 %) vs 6 (4 %)] (all p < 0.01). Median follow-up was 4.8 years. iENE+/cENE– and iENE+/cENE+patients had similarly low 5-year OS [28 % (18–44) and 29 % (13–63)] vs iENE–/cENE– [53 % (45–62)] (p < 0.001). On MVA, mortality risk was higher with iENE+vs iENE– [hazard ratio (HR) 2.22 (95 % CI 1.47–3.36)]. The prognostic value of iENE remained with MVA in larynx (n = 124) (HR 2.51 [1.35–4.68], p = 0.004] or hypopharynx (n = 108) (HR 1.87 [1.02–3.43], p = 0.04) patients, separately. ConclusionsOur study confirms the independent prognostic importance of iENE for LHC following definitive (chemo-)radiotherapy beyond TNM-8 cN status that already contains the cENE parameter. Further research is needed to explore whether iENE could replace cENE for future cN classification.