Circulating Tumor DNA (ctDNA) – A Potential Adjunct to FDG-PET Imaging in Cancer Follow Up

TEACHING POINTS

With the continuous advances in healthcare - Next Generation Sequencing and PET-CT are revolutionising cancer diagnostics
Survival outcomes in cancer can be improved by early detection of metastatic disease or relapse during follow up
Next Generation sequencing is an extremely high end modality wherein hundreds to millions of DNA molecules are sequenced in parallel
CtDNA is an application of NGS to monitor the amount of tumor specific DNA in the peripheral blood of patient
Using ctDNA, a non-invasive investigation, to monitor the remission status can potentially reduce the frequency of imaging required at follow up, hence reducing the side effects and discomfort
According to Wong R et al, for colorectal cancer patients with indeterminate findings on routine investigations, ctDNA detection increases the probability that the findings indicate metastatic disease, including in a nonpredefined subset that also underwent FDG-PET imaging
Hence, using ctDNA as an adjunct to FDG-PET imaging during cancer follow-up seems to be an acceptable proposition.