1076O Primary analysis of the EORTC 1208 Minitub trial: Prospective registry of sentinel node (SN) positive melanoma patients with minimal SN tumor burden

Published Date: 20th September 2024

Publication Authors: Brackley. P

Background
Retrospective studies have shown the prognostic value of SN tumor burden (van der Ploeg et al. JCO 2011). There are different ways to assess SN tumor burden, e.g. as the microanatomic location (Dewar et al. JCO 2004) or the diameter of the largest deposit (van Akkooi et al. Ann Oncol 2006). The aim of this study was to determine outcomes of patients (pts) with minimal SN tumor burden, managed without complete lymph node dissection (CLND).

Method(s)
Melanoma pts with minimal SN tumor burden were prospectively followed. Pts were seen every 4 months (yr 1-2), 6 months (yr 3-5) and annually (yr 6-10). They had baseline imaging. An ultrasound of the lymph nodes at every visit was advised. The hypothesis was that the cumulative incidence of distant metastasis at 5 years was lower than 20% in pT2-3 pts.

Result(s)
Between 2015 and 2021, 296 pts were recruited from 21 centers in 9 countries; 17 CLND and 279 observation (OBS), incl. 201 with pT2-3; 149 were eligible (main group). Central pathology review demonstrated 33 pts (11%) did not harbor metastases (macrophages/benign capsule nevi) and 36 (12%) no minimal SN tumor burden. Median follow-up was 4.5 yrs (IQR 3.0 - 5.5 yrs). The cumulative incidence of distant metastasis and death due to melanoma at 5 yrs were 15% (90% CI 10-21%, one-sided p=0.096) and 8% in the main group and 8% & 6% among all patients from OBS group with AJCC8 stage IIIA. SN tumor burden (> 0.1 vs < 0.1 mm)[HR 2.35, P=0.022] and AJCC stage [HR 3.09 for IIIB vs IIIA and 5.01 for IIIC vs. IIIA, P<0.001] were independent prognostic factors. [Formula presented]

Conclusion(s)
Central review revealed overdiagnosis in 11%. This first and only prospective study of melanoma pts with minimal SN tumor burden demonstrated low rates of distant metastases or death. SN tumor burden was an independent prognostic factor, and it should be considered to be added to future staging systems for improved prognostication, allowing to spare low-risk stage III pts the potential toxicity of adjuvant therapy.

van Akkooi, ACJ; Brackley, P et al. (2024). 1076O Primary analysis of the EORTC 1208 Minitub trial: Prospective registry of sentinel node (SN) positive melanoma patients with minimal SN tumor burden. Annals of Oncology. 35(Supplement 2), p.S712. [Online]. Available at: https://doi.org/10.1016/j.annonc.2024.08.1144 [Accessed 2 October 2024].

 

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