Patterns of lymphatic spread in laryngeal squamous cell carcinoma and personalization of the elective clinical target volume.

Abstract

Aiming for personalization of elective clinical target volumes (CTV), we are reporting on regional lymphatic spread patterns in laryngeal squamous cell carcinoma (SCC), considering not only subsite, T-stage, and lateralization of the primary tumor, but also involvement of adjacent lymph node levels (LNLs). LNL involvement in 1005 patients with laryngeal SCC treated at University Hospital Zurich between 2013 and 2021 and UMCG Groningen between 2006 and 2023 was analyzed. LNL involvement was assessed based on imaging and, if available, pathology. Patterns of LNL involvement can be visualized on https://lyprox.org/. For T2-glottic tumors (N = 193), involvement was <4% in all LNLs, supporting the hypothesis that ENI could potentially be omitted. In T3/T4-glottic patients without ipsilateral LNL II involvement (N = 198), involvement of LNLs III and IV was 5% and 1%, suggesting that ENI of LNL IV could be omitted in cN0 patients. For T3/T4-glottic tumors (N = 239) almost no contralateral involvement was observed for lateralized tumors (N = 37), suggesting contralateral treatment could potentially be omitted or limited to LNL II in patients with clinically negative contralateral neck. For supraglottic SCC without midline extension of the primary tumor (N = 75), contralateral LNL involvement was below 3%. In patients with midline extension but without contralateral LNL II involvement (N = 193), involvement of downstream levels was rare (LNL III 5%, LNL IV 3%). We provided detailed information about lymphatic spread patterns of laryngeal SCC, depending on subsite, T-stage, lateralization, and upstream involvement. Subgroups of patients can be identified in whom the elective CTV or surgical approach may be reduced compared to current guidelines.