Researchers from The University of Sydney have found that patients with thin primary melanomas measuring 0.8 to 1.0 millimeters face a significantly higher risk of melanoma-related death compared to those with thinner lesions.
The findings, published in JAMA Dermatology, analyzed data from Australian cancer registries spanning 1982 to 2014. Australia, which has the world’s highest melanoma incidence, provided a robust dataset for this analysis, given its decades-long practice of tracking thin melanomas, typically classified as 1.0 mm or less in thickness.
The study highlights the importance of subtle increases in Breslow thickness — measured in 0.1-mm increments — in predicting survival outcomes. Of the 144,447 patients included in the study, those with tumors under 0.8 mm had a 20-year survival rate of 94.2%, while survival dropped to 87.8% for patients with tumors measuring 0.8 to 1.0 mm. The overall 20-year melanoma-specific survival rate across all groups was 91.9%.
As reported by medicalxpress, the results support the use of the 0.8-mm Breslow thickness threshold as a key factor in cancer staging criteria set by the American Joint Committee on Cancer. They also highlight the need for long-term follow-up, as melanoma-related deaths continued to accumulate beyond 20 years after diagnosis.
“These findings emphasize the clinical significance of even slight increases in tumor thickness,” the researchers noted, adding that the data could inform personalized monitoring and management strategies for melanoma patients.