Regression may predict good prognosis in stage 1 and 2 cutaneous melanomas
Disease regression was associated with improved recurrence-free survival and overall survival among certain patients with stage 1 and 2 cutaneous melanomas, according to a study.
“Although regression is commonly observed in cutaneous melanoma, it is uncertain whether it is associated with patient prognosis,” Mary-Ann El Sharouni, MD, of the Melanoma Institute Australia at The University of Sydney and the department of dermatology at University Medical Center Utrecht at Utrecht University, the Netherlands, and colleagues wrote.
In the cohort study involving 17,271 Dutch patients and 4,980 Australian patients with stage 1 and 2 primary cutaneous melanomas, the researchers aimed to determine whether histologically confirmed regression was associated with better or worse survival. Population-based data were used to accrue Dutch patients, while data from a large, specialized melanoma treatment center were used in Australia.
Eligible participants underwent treatment between 2000 and 2014. Dutch patients were followed for a median duration of 4.5 years, while those in Australia were followed for a median of 11.1 years.
Recurrence-free survival (RFS) and overall survival (OS) served as the primary outcome measures.
Results from the Dutch cohort showed that disease regression predicted RFS (HR = 0.55; 95% CI, 0.48-0.63; P < .001) and OS (HR = 0.87; 95% CI, 0.79-0.96; P = .004).
A similar outcome was reported in the Australian cohort, with disease regression predicting both RFS (HR = 0.61; 95% CI, 0.52-0.72; P<.001) and OS (HR = 0.73; 95% CI, 0.64-0.84; P<.001).
Looking at subgroups, in patients with superficial spreading melanoma (SSM), regression yielded improvement in RFS in both the Dutch cohort (HR = 0.54; 95% CI, 0.46-0.63; P<.001) and the Australian cohort (HR = 0.67; 95% CI, 0.52-0.85; P=.001). Regression among patients with SSM also carried an association with improved OS in the Dutch (HR = 0.86; 95% CI, 0.76-0.96; P=.009) and Australian (HR = 0.72; 95% CI, 0.59-0.88; P=.001) populations.
Regarding tumor thickness, regression was associated with improved RFS among patients with both thin and intermediate Breslow thickness melanomas.
Digging deeper into these findings, regression improved OS in patients with thin melanomas in the Australian cohort only (HR = 0.66; 95% CI, 0.50-0.88; P = .004), not in the Dutch cohort.
For patients with thick melanomas, regression failed to correlate with either RFS (HR = 0.74; 95% CI, 0.53-1.02;) or OS (HR = 1.07; 95% CI, 0.83-1.38) in the Dutch cohort. For Australian patients with thick tumors, again, regression failed to improve RFS (HR = 0.91; 95% CI, 0.65-1.29) or OS (HR = 0.78; 95% CI, 0.57-1.08).
“Consistent with several previous reports, the results of this study, by far the largest reported to date, indicate that regression can be considered a favorable prognostic factor for patients with stage 1 and stage 2 melanomas,” the researchers wrote. “Those with thin and intermediate-thickness tumors (Breslow thickness 4.0 mm) and those with SSM subtype are most likely to have an improved prognosis when regression is present.”