The ECS-absent SLN– disease group had the most favorable survival outcomes, while those with ECS-present N+ disease had the worst outcomes. The prognosis of ECS-present, SLN+ patients was statistically similar to the ECS-absent, N+ group, she said.
In patients with SLN+ disease, Breslow thickness and N-stage were independent prognostic indicators for progression-free survival (hazard ratio 2.4, P less than .0001) and disease-free survival (HR 2.3, P less than .0001), Dr. Lo noted that median progression-free survival in SLN+ and N+ disease was 20 and 10 months, respectively. “Within our cohort of patients with ECS present in the micrometastatic group, their disease progressed within 3 years,” she said.
A multivariate analysis showed the survival data from this study was consistent with American Joint Committee on Cancer staging criteria, Dr. Lo said. “ECS is well recognized in the macrometastatic group, but we demonstrated from our data that the incidence of ECS in the micrometastatic group is one in six. It’s an independent risk factor for disease progression and an independent risk factor for worst disease-specific and overall survival, and it upstages micrometastatic disease.” ECS upstages stage III disease in a fashion similar to that of ulceration in primary melanoma, she said.
“In the absence of data to suggest otherwise, we would still recommend completion lymph node dissection in our micrometastatic group where ECS is present, and we would advocate that ECS should be included as an independent staging variable in the future,” Dr. Lo said.
Dr. Lo and her coauthors reported having no financial disclosures.
SOURCE: Lo M, et al. SSO 2018 Abstract 70.