Risk Stratification of Sentinel Node Metastasis Disease Burden and Phenotype in Stage III Melanoma Patients

Abstract

Background Currently, all patients with American Joint Committee on Cancer (AJCC) pT2b-pT4b melanomas and a positive sentinel node biopsy are now considered for adjuvant systemic therapy without consideration of the burden of disease in the metastatic nodes. Methods This was a retrospective cohort analysis of 1377 pT1-pT4b melanoma patients treated at an academic cancer center. Standard variables regarding patient, primary tumor, and sentinel node characteristics, in addition to sentinel node metastasis maximum tumor deposit size (MTDS) in millimeters and extracapsular spread (ECS) status, were analyzed for predicting disease-specific survival (DSS). Results The incidence of SN+ was 17.3% (238/1377) and ECS was 10.5% (25/238). Increasing AJCC N stage was associated with worse DSS. There was no difference in DSS between the IIIB and IIIC groups. Subgroup analyses showed that the optimal MTDS cut-point was 0.7 mm for the pT1b-pT4a SN+ subgroups, but there was no cut-point for the pT4b SN+ subgroup. Patients with MTDS <0.7 mm and no ECS had similar survival outcomes as the N0 patients with the same T stage. Nodal risk categories were developed using the 0.7 mm MTDS cut-point and ECS status. The incidence of low-risk disease, according to the new nodal risk model, was 22.3% (53/238) in the stage III cohort, with 49% (26/53) in the pT2b-pT3a and pT3b-pT4a subgroups and none in the pT4b subgroup. Similar outcomes were observed for overall and distant metastasis-free survival. Conclusion We propose a more granular classification system, based on tumor burden and ECS status in the sentinel node, that identifies low-risk patients in the AJCC IIIB and IIIC subgroups who may otherwise be observed.

The “Great Debate” at Melanoma Bridge 2022, Naples, December 1st–3rd, 2022

“…In a retrospective study of 1377 patients with pT1–pT4b primary cutaneous melanoma, the optimal maximum tumour deposit size cut-point was 0.7 mm for the pT1b-pT4a SLN-positive subgroups, but there was no cut-point for SLN-positive patients with pT4b melanoma [ 46 ]. Nodal risk categories were developed using the 0.7 mm maximum tumour deposit size cut-point and extracapsular spread status.…”

ASO Author Reflections: Risk Stratification of Sentinel Node Metastases in Stage III Melanoma Patients in the Era of Adjuvant Systemic Therapy

“…This work by Hussain et al 3 is an extension of the research recently undertaken by an international consortium, which stratified the risk recurrence and death in a pT1b-pT2a SNB-positive (American Joint Committee on Cancer [AJCC] IIIA) cohort of patients. 4 In that study, maximum tumor deposit size (MTDS) was found to be the optimal phenotypical biomarker for this ostensibly low-risk group.…”