Earlier Recurrence Detection Using Routine FDG PET-CT Scans in Surveillance of Stage IIB to IIID Melanoma: A National Cohort Study of 1480 Patients

BACKGROUND: The effect of routine imaging in melanoma surveillance is unknown. In 2016, Denmark was the first country in the world to implement routine imaging with positron emission tomography-computed tomography with fluorodeoxyglucose (FDG PET-CT) in a nationwide, population-based surveillance program. This study aimed to determine the impact of surveillance with routine FDG PET-CT on hazard, cumulative incidence, and absolute risk of overall, locoregional, and distant recurrence detection in patients with stage IIB to IIID cutaneous melanoma.

METHODS: This retrospective, population-based, nationwide cohort study used prospectively collected data from five national health registries to compare hazard, cumulative incidence, and absolute risk of recurrence in patients with cutaneous melanoma diagnosed in 2008-2010 (cohort 1, followed with clinical examinations) and patients with cutaneous melanoma diagnosed in 2016-2017 (cohort 2, followed with clinical examinations and routine FDG PET-CT at 6, 12, 24, and 36 months).

RESULTS: The study included 1480 patients with stage IIB to IIID cutaneous melanoma. Cumulative incidences of overall and distant recurrence were higher in cohort 2, with a peak difference at three years (32.3 % vs 27.5 % and 25.8 % vs. 18.5 %, respectively). The hazard of recurrence was higher in cohort 2 during the first two years, with hazard rates for overall and distant recurrence of 1.16 (95 % confidence interval [CI], 0.93-1.44) and 1.51 (95 % CI, 1.16-1.96), respectively. The patterns persisted in absolute risk estimates.

CONCLUSIONS: Patients with stage IIB to IIID melanoma followed with routine FDG PET-CT had a 51 % increased hazard of distant recurrence detection within the first two years of surveillance. Future studies must determine whether this earlier recurrence detection translates into improved survival.