Correlation between circulating tumour DNA and metabolic tumour burden in metastatic melanoma patients
Ashleigh McEvoy, Edith Cowan UniversityFollow
Michelle R. Pereira
Muhammad A. Khattak
Tarek M. Meniawy
Mel R. Ziman Dr, Edith Cowan UniversityFollow
Elin S. Gray, Edith Cowan UniversityFollow
BioMed Central Ltd.
Place of Publication
School of Medical and Health Sciences
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.