Risk of recurrence of stage I to III melanoma in Norway, 2008-2022

Contemporary population-based data on patterns of melanoma recurrence remain limited, yet are required for planning treatment and surveillance. We aimed to estimate the risk of recurrence following a first primary invasive melanoma, by time since diagnosis, and by patient and tumour characteristics.

This nationwide cohort study included patients aged ≥ 18 years with a first primary melanoma, stage I-III (American Joint Committee on Cancer, 8th Edition), recorded by the Cancer Registry of Norway in 2008-2021. Patients were followed-up until the first melanoma recurrence, death (without recurrence), or 10 years post-diagnosis, whichever occurred first. Study outcomes were cumulative risk, overall and by patient and tumour characteristics, were estimated using the Aalen-Johansen estimator.

Among 24,095 included patients, 3276 experienced a recurrence, while 2844 died without recurrence. The cumulative recurrence risk increased rapidly from 5.8% (95% confidence interval, (CI): 5.5-6.1%) at 1 year to 11.1% (CI: 10.6-11.5%) at 3 years and then rose more gradually to a 10-year recurrence risk of 16.7% (CI: 16.2-17.3%). Death without recurrence increased steadily throughout follow-up. The highest 10-year recurrence risks were observed in men (20.6%), patients aged 70-79 (20.8%), TNM stage III (47.8%) and those with tumours > 4.00 mm thick (43.4%), or melanomas that were ulcerated (37.0%), nodular (31.5%), or on the head/neck (21.7%).

10-year recurrence risk after diagnosis of a first primary melanoma was 16.7%, compared with 17.8% risk of death without recurrence. These findings provide an empirical basis for risk-stratified surveillance strategies, particularly during the early follow-up period.