The impact of type 2 diabetes on sex- and stage-specific melanoma recurrence and mortality: A Danish cohort study, 2004 to 2024

Jens E Lyngstrand; Eeva-Liisa Røssell; Marie L Bønnelykke-Behrndtz; Tinne Laurberg

doi:10.1093/bjd/ljag097

The impact of type 2 diabetes on sex- and stage-specific melanoma recurrence and mortality: A Danish cohort study, 2004 to 2024

Br J Dermatol. 2026 Mar 15:ljag097. doi: 10.1093/bjd/ljag097. Online ahead of print.

Authors

Jens E Lyngstrand^{1

2}, Eeva-Liisa Røssell¹, Marie L Bønnelykke-Behrndtz², Tinne Laurberg^{1

3}

Affiliations

¹ Steno Diabetes Centre Aarhus, Aarhus University Hospital, Aarhus, Denmark.
² Department of Plastic and Breast Surgery, Aarhus University Hospital, Aarhus, Denmark.
³ Department of Pathology, Aarhus University Hospital, Aarhus, Denmark.

PMID: 41831481
DOI: 10.1093/bjd/ljag097

Abstract

Background: The incidence of both melanoma and type 2 diabetes (T2D) is increasing. Recent studies suggest that T2D is associated with a more advanced melanoma stage at diagnosis, but its impact on melanoma prognosis remains unclear.

Objectives: To examine the impact of T2D on sex- and stage-specific melanoma recurrence, melanoma-specific mortality, and overall mortality.

Methods: This population-based cohort study included all Danish patients diagnosed with melanoma between 2004 and 2022, excluding those with prior cancer or type 1 diabetes. The impact of T2D on melanoma recurrence, melanoma-specific mortality, and overall mortality was assessed by stage (AJCC stage I-II [localised], stage III [locoregional], and stage IV [metastatic]) and stratified on sex. Cumulative incidence proportions and risk differences (RD) were estimated. Furthermore, regression analyses using competing risk models to estimate adjusted hazard ratios (aHR) were applied, adjusting for age, comorbidity, calendar year, and stage at diagnosis. Patients were from date of melanoma diagnosis and followed until death, emigration, or the end of the study period (December 31, 2024).

Results: This study included 30,365 individuals diagnosed with melanoma; 14,343 were males (1,195 with T2D) and 16,022 were females (816 with T2D), with higher event frequencies in males than females. Among males with localised melanoma, T2D was associated with higher 5-year risks of recurrence (15.0% vs 8.3%, aHR 1.30, 95% CI 1.08-1.56) and melanoma-specific mortality (8.5% vs 4.2%, aHR 1.28, 1.00-1.64). Among women with localised melanoma, the T2D associated risk differences were less pronounced and no associations was observed after adjustment: Recurrence aHR: 1.04 (0.78-1.38), and Melanoma-specific mortality aHR: 1.10 (0.75-1.61). For both sexes with either locoregional or metastatic melanoma, T2D had no prognostic impact.

Conclusion: T2D was associated with poorer prognosis among males with localised melanoma, whereas no prognostic impact was observed among females or patients with more advanced disease. These findings indicate the need for closer follow-up of males with early-stage melanoma and T2D, and for further studies to clarify underlying mechanisms and the potential benefits of optimised diabetes management.