Melanoma Mortality Rises at 0.8-mm Thickness, Study Finds

TOPLINE:

The risk for melanoma-related death was higher in individuals with tumors with a Breslow thickness of 0.8-1.0 mm than in individuals with tumors smaller than 0.8 mm, in an Australian study that used registry data.

METHODOLOGY:

• The study analyzed 144,447 individuals (median age, 56 years, 54% men) diagnosed with thin (T1) primary invasive melanomas (Breslow thickness, ≤ 1.0 mm) between 1982 and 2014 from all eight Australian state and territory population-based cancer registries.
• The researchers evaluated the associations between Breslow thickness (
• The primary endpoint was time to death attributable to a melanoma-related cause, with death due to a nonmelanoma-related cause as a competing event.

TAKEAWAY:

• The 20-year cumulative incidence of melanoma-related deaths was 6.3% for the whole cohort. The incidence was higher for tumors with a thickness of 0.8-1.0 mm (11%) than for those with a thickness
• The overall 20-year melanoma-specific survival rate was 95.9%, with rates of 94.2% for tumors
• A multivariable analysis revealed that a tumor thickness of 0.8-1.0 mm was associated with both a greater absolute risk for melanoma-related deaths (subdistribution hazard ratio, 2.92) and a higher rate of melanoma-related deaths (hazard ratio, 2.98) than a tumor thickness
• The 20-year incidence of death from nonmelanoma-related causes was 23.4%, but the risk for death from these causes showed no significant association with Breslow thickness categories.

IN PRACTICE:

“The findings of this large-scale population–based analysis suggest the separation of risk for patients with melanomas with a Breslow thickness above and below 0.8 mm,” the authors wrote, adding: “These results suggest that a change of the T1 threshold from 1.0 mm to 0.8 mm should be considered when the AJCC [American Joint Committee on Cancer] staging system is next reviewed.”

SOURCE:

The study was led by Serigne N. Lo, PhD, Melanoma Institute Australia, The University of Sydney, Sydney, Australia. It was published online on December 11, 2024, in JAMA Dermatology.

LIMITATIONS:

The study was registry-based and did not capture details such as tumor characteristics and treatment modalities. Inaccuracies in reporting the cause of death may have led to an underestimation of melanoma-specific mortality risks across all thickness groups and an overestimation of nonmelanoma mortality risks.

DISCLOSURES:

The study received funding support from Melanoma Institute Australia and two grants from the Australian National Health and Medical Research Council (NHMRC). Several authors reported receiving grants or personal fees from or having ties with various sources, including NHMRC.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.