The following is a summary of “Clinical Outcomes and Risk Stratification of Early-Stage Melanoma Micrometastases From an International Multicenter Study: Implications for the Management of American Joint Committee on Cancer IIIA Disease” published in the December 2022 issue of Oncology by Moncrieff et al.

There was a debate concerning the justifications for administering adjuvant systemic therapy to patients with early-stage melanomas with sentinel node (SN) micrometastases with modest disease burden or stage IIIA disease, according to the American Joint Committee on Cancer (AJCC; eighth edition). For a study, researchers sought to identify AJCC stage IIIA patients with high-risk SN positivity who were more likely to benefit from adjuvant systemic therapy.

Nine high-volume cancer hospitals across three continents (North America, Europe, and Australia) were used to source patients for the study. All underwent SN biopsy between 2005 and 2020 and were adult patients with pathologic stage pT1b/pT2a primary cutaneous melanomas. The features of the original tumor, the SN, and the patient data were examined.

About 3,600 seven patients were included. Around 34 months was the average follow-up. There was no discernible survival difference between the N1a and N2a groupings, according to pairwise illness comparison. An SN tumor deposit with a maximum diameter of 0.3 mm was shown to be the ideal cut point for survival analyses. Patients with SN metastatic tumor deposits that were ≥0.3 mm and < 0.3 mm had five-year disease-specific survival rates of 80.3% and 94.1%, respectively (hazard ratio, 1.26 [1.11 to 1.44]; P< .0001). For overall disease-free survival and distant metastasis-free survival, comparable results were observed. Between low-risk (<0.3 mm) AJCC IIIA patients and AJCC IB patients 142 (34.8%) had SN tumor deposits with a maximum size of >1 mm, while 271 (66.4%) of the AJCC IIIA cohort belonged to the newly identified high-risk ( 0.3 mm) subgroup.

A clinical trial or adjuvant systemic therapy may be beneficial for patients with AJCC IIIA melanoma who have SN tumor deposits that are ≥0.3 mm in maximum dimension because they are at an increased risk of the disease progressing. Patients with SN deposits that are <0.3 mm in maximum dimension can be treated in a manner similar to that of their SN-negative, AJCC IB counterparts, avoiding the need for more frequent radiological monitoring.

Reference: ascopubs.org/doi/full/10.1200/JCO.21.02488