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Updated: Feb 8, 2026

Electrochemotherapy of Tumours
Published on: December 15, 2008
Correlation between circulating tumour DNA and metabolic tumour burden in metastatic melanoma patients
Ashleigh C McEvoy1, Lydia Warburton2, Zeyad Al-Ogaili3
1School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA, 6027, Australia.
Background:
Circulating tumour DNA (ctDNA) may serve as a measure of tumour burden and a useful tool for non-invasive monitoring of cancer. However, ctDNA is not always detectable in patients at time of diagnosis of metastatic disease. Therefore, there is a need to understand the correlation between ctDNA levels and the patients' overall metabolic tumour burden (MTB).
Methods:
Thirty-two treatment naïve metastatic melanoma patients were included in the study. MTB and metabolic tumour volume (MTV) was measured by 18F-fluoro-D-glucose positron emission tomography/computed tomography (FDG PET/CT). Plasma ctDNA was quantified using droplet digital PCR (ddPCR).
Results:
CtDNA was detected in 23 of 32 patients. Overall, a significant correlation was observed between ctDNA levels and MTB (p < 0.001). CtDNA was not detectable in patients with an MTB of ≤10, defining this value as the lower limit of tumour burden that can be detected through ctDNA analysis by ddPCR.
Conclusions:
We showed that ctDNA levels measured by ddPCR correlate with MTB in treatment naïve metastatic melanoma patients and observed a limit in tumour size for which ctDNA cannot be detected in blood. Nevertheless, our findings support the use of ctDNA as a non-invasive complementary modality to functional imaging for monitoring tumour burden.
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