Background: Merkel cell carcinoma (MCC) is an aggressive skin cancer with a recurrence rate of 40%. This prospective, multicenter study assessed whether circulating tumor DNA (ctDNA) can assess disease burden and detect early recurrence.
Methods: Whole-exome sequencing was performed on tumor tissue and matched to normal blood to create a personalized and multiplex PCR-NGS based ctDNA assay. 328 blood samples were collected from 125 patients between April 2020 to January 2022.
Results: Among 125 patients, 47 had clinically evident MCC and all were found to be ctDNA-positive at the first time point. Of the 125 patients, 73 (58%) were assessed in the surveillance setting. A total of 152 plasma samples were available for longitudinal ctDNA testing, 7 of which were positive, and recurrence developed after 5/7 of the positive tests. Of the remaining 2 without recurrence, one had <60 days of follow-up at time of analysis. After a negative ctDNA test, the risk of recurrence was 0% within 60 days and 3% between 60-90 days.
Conclusion: ctDNA can detect MCC recurrence early and is a promising clinical surveillance tool.
Background: Merkel cell carcinoma (MCC) is an aggressive skin cancer with high mortality and recurrence rates. Circulating tumor DNA (ctDNA) is a small fragment of DNA that is released from tumor cells, and can be found in the blood of cancer patients. This study looked at whether ctDNA can detect recurrence early and function as a “liquid biopsy.”
Methods: Tumor tissue and blood was collected on 125 patients with MCC between April 2020 and January 2022.
Results: Among 125 patients, 47 were ctDNA-positive at the first blood draw. After being treated for their cancer, 73 (58%) of the 125 patients were followed longitudinally, with a total of 152 plasma samples. 7 of the tests were positive, and recurrence was detected in 5 of these 7 patients. In contrast, after a negative ctDNA test, the risk of recurrence was 0% within 60 days and 3% between 60-90 days.
Conclusion: ctDNA can detect MCC recurrence early. After being treated for cancer, patients with a negative test may have a very low chance of recurrence.