Routine imaging with PET-CT demonstrated high sensitivity and specificity in patients with asymptomatic, high-risk melanoma, according to study results published in the European Journal of Surgical Oncology.
The study authors explained that the utility of routine imaging with PET-CT in melanoma is “debated,” and “evidence of its diagnostic value and yield in asymptomatic patients is limited.”
The study was based on prospectively registered clinical data from the Danish Melanoma Database and retrospectively collected data from patient records.
The study cohort comprised 138 patients diagnosed with asymptomatic, stage IIB-III melanoma at 2 Denmark University Hospitals in 2016 and 2017. Routine surveillance with PET-CT in patients with high-risk melanoma started in Denmark in 2016.
Overall, 243 routine PET-CTs were done for 138 patients within a median follow-up of 17.7 months after primary treatment.
There were 43 recurrences identified in 25 patients (18.1%), including 19 patients (13.8%) with distant recurrence.
Recurrence rates by disease stage were 11.1% for IIB, 40.0% for IIC, 13.9% for IIIA, 23.5% for IIIB, and 20.0% for IIIC.
The median time to recurrence detected by routine PET-CT was 7.0 months. The numbers-needed-to-scan was 8.1 patients for any recurrence and 12.8 patients for distant recurrence.
Results from scans led to management changes for 24 situations in 20 patients (14.5%).
Routine PET-CT showed a 100% sensitivity and a 94.7% specificity as well as a negative predictive value of 100% and a positive predictive value of 74.4%.
The false-positive rate was 4.5% for both melanoma recurrence and findings of other cancers. False-positive findings led to additional investigations in 17 patients (12.3%), including invasive procedures for 9 patients (6.5%).
“We recommend that early surveillance imaging with PET-CT at 6 months be considered for stage IIC-III patients, whereas early routine imaging appears to have a limited yield in stage IIB patients,” the study authors wrote. “Routine PET-CT for the surveillance of high-risk melanoma patients has a high diagnostic value, but large-scale prospective studies . . . must show whether the shorter time-to-recurrence detection translates into earlier treatment and ultimately improved survival.”
Disclosures: This research was supported by the Danish Cancer Society, the Danish Cancer Research Foundation, and the Research Council at Herlev Gentofte Hospital. The study authors disclosed no competing interests.
Helvind NM, Mardones CAA, Hölmich LR, et al. Routine PET-CT scans provide early and accurate recurrence detection in asymptomatic stage IIB-III melanoma patients. Eur J Surg Oncol. Published online June 6, 2021. doi:10.1016/j.ejso.2021.06.011