The detection of circulating tumour DNA (ctDNA) in blood or urine, known as ‘liquid biopsies’, is an established method for non-invasive monitoring of many cancers, such as breast, lung and colorectal cancer. The current study was the most extensive analysis of ctDNA in kidney cancer patients to date, involving urine and blood samples from 91 kidney cancer patients.
However, the researchers were surprised to find that the levels of ctDNA in blood and urine were much lower in patients with kidney cancer tumours than those observed for other solid cancers of a similar size and stage. This was an unexpected finding, given that kidney cancer is an aggressive cancer in an organ with a profuse blood supply. Using a combination of advanced DNA sequencing methods, the researchers were able to detect ctDNA in the blood and urine of about half of the patient samples.
The researchers suggest that regular testing of urine and blood can identify if tumour cells are still present after treatment for some patients, and could be used in the future to aid the clinical management of kidney cancer patients.