Hazard rates and implications for follow-up schedules of melanoma patients with 0.8–1.0 mm tumor thickness: An analysis of the German Central Malignant Melanoma Registry in 12,132 patients

<h2>Abstract</h2><h3>Background</h3> Understanding the risk of recurrence is crucial for planning of follow-up in cutaneous melanoma patients. <h3>Objectives</h3> This study aims to analyze time-dependent hazard rates (HR) for recurrences concerning follow-up recommendations for thin melanomas. <h3>Methods</h3> 12,132 patients in stages IA/IB were recorded by the German-Central-Malignant-Melanoma-Registry in 2000–2010. Survival rates, based on Kaplan-Meier estimates, and HR were calculated comparing three groups of tumor thickness (TTH). <h3>Results</h3> Recurrences were recorded in 916/12,132 patients (7.6 %), in 3.7 % with TTH < 0.8 mm, 9.8 % with TTH 0.8–1.0 mm and 15.8 % with TTH > 1.0–2.0 mm. Median follow-up-time was 48.0 months (IQR: 23.0;78.0) in tumors < 0.8 mm; 54.0 months (25.0;84.0) in tumors of 0.8–1.0 mm, 61.0 months (30.0;91.0) in tumors of 1.01–2.0 mm. Ten-year recurrence-free survival (RFS) was 91.5 % (95 %-CI: 90.1 %;92.9 %) in tumors with TTH < 0.8 mm; 81.9 % (79.0 %;84.8 %) with TTH 0.8–1.0 mm and 74.0 % (71.5 %;76.6 %) with TTH 1.01–2.0 mm. In years 1–5, HR for recurrences showed levels of ≤ 1:1111 per year for TTH < 0.8 mm, undulating but higher HR up to 1:313 in TTH of 0.8–1.0 mm and up to 1:222 in TTH of ≥ 1.01 mm. <h3>Limitations</h3> Few information can be given beyond a follow-up of 10 years. <h3>Conclusion</h3> Low HR were found for stage IA patients and TTH < 0.8 mm, therefore reduced surveillance intervals seem appropriate. Melanoma with a TTH of 0.8–1.0 mm showed higher HR rates, similar to stage IB patients. These data indicate that these patients may need more intensive follow-up in the first years.