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QS22. Survival and recurrence outcomes for stage IIB/IIC melanoma: risk stratification for immunotherapy and surveillance

Thursday, March 5, 2026
3:45 PM - 3:49 PM MST
Location: Immuno-Oncology HUB Zone
Introduction:

Stage IIB/IIC cutaneous melanoma (CM) has a poor prognosis. Adjuvant immunotherapy (IO) is offered to these patients (pts); however, it benefits only a small subset. Current benchmarks of the AJCC and German national registries (CMMR) vary significantly in survival estimates for this important group. This study provides an additional, international assessment of this group and identifies factors associated with increased risk of recurrence to guide adjuvant IO and surveillance.



Methods:

This multi-institutional, international retrospective cohort study analyzed the Sentinel Lymph Node (SLN) Working Group database on pts with pathologic (p) tumor category T3b/T4a/T4b and pN0 disease who underwent surgical resection and SLN biopsy from 1994- 2025. Clinicopathologic and demographics variables were correlated with recurrence risk, recurrence location and survival.



Results:

We identified 2514 pts (1648 stage IIB CM (65.6%) and 866 stage IIC (34.4%)) from 19 sites in 4 countries. Median age was 66.9 years (IQR 57, 76) and 1579 (62.8%) were male. Median Breslow thickness was 4.5 mm (IQR 3.1,6.0). 136 pts (5.4%) received adjuvant IO. 679 pts recurred (92 (14%) local, 238 (35%) regional and 345 (51%) distant as initial site). Median follow-up was 53.2 and 49.7 months for stage IIB and IIC respectively. On Kaplan-Meier analysis, stage IIB pts demonstrated improved recurrence free survival (RFS; 58% vs 43%, p< 0.0001), disease-specific survival (DSS; 86% vs 79%, p< 0.0001) and overall survival (OS; 74% vs 63%) at 5 years.



On multivariable analysis, OS (HR 0.81) and RFS (HR 0.83) were higher for female pts. Lymphovascular invasion (LVI) and ulceration were associated with worse OS (HR 1.84, 1.43), DSS (HR 2.07, 1.49) and RFS (HR 1.54, 1.43). Increasing Breslow thickness was associated with a higher risk of recurrence and worse survival outcomes, with tumors >4mm RFS, DSS, and OS (HR 1.70, 1.98, 1.62) and tumors 3-4mm RFS and DSS (HR 1.69,1.30).



Mitotic rate, tumor regression, preexisting lesions and presence of tumor infiltrating lymphocytes were not significant.



Conclusions:

In this large, international cohort; LVI, ulceration, male sex and thickness >3mm were independent predictors of worse survival and higher risk of recurrence. This supports using these factors to better stratify pts for consideration of adjuvant IO and increased surveillance. Additionally, survival outcomes were consistent with previous benchmarks, particularly for stage IIB pts. Five year DSS for stage IIC fell between AJCC (82%) and CMMR (76.6%) which may indicate that the true outcome is intermediate to these.

Learning Objectives:

  • Identify key clinicopathologic and demographic predictors of recurrence and survival in patients with Stage IIB/IIC cutaneous melanoma
  • Describe the 5-year survival outcomes (RFS, DSS, OS) for patients with stage IIB/IIC melanoma from our study and compare these findings to established benchmarks
  • Consider how high-risk features, such as lymphovascular invasion and ulceration, can be utilized to better stratify patients for adjuvant immunotherapy and surveillance