Is the Cancer Treatment Working? Liquid Biopsies Provide Answers.

A newly-developed tool could help physicians monitor the performance of colorectal cancer therapies simply by examining a patient’s blood or urine. This liquid biopsy technique can flag for the presence of trace amounts of cancer after treatment, providing a guide for whether to stop or continue further courses of treatment. The study was published in the Journal of Clinical Oncology Precision Oncology. 

Liquid biopsies are tests that look for DNA originating from tumor cells circulating in the blood. They are typically used to sniff out the early signs of cancer, but by taking multiple samples over time, doctors can map a tumor’s responses to cancer treatments. A handful of liquid biopsies for lung, prostate, and breast cancers have been approved for clinical use, but none are available for colorectal cancer applications. 

“Being able to measure the response to early chemotherapy without prior knowledge of the tumor’s mutations is a novel idea and important for being able to determine whether the patient responded well to the therapy,” said the study’s senior author, Aadel A. Chaudhuri.

Not all patients with colorectal cancer respond to chemotherapy in the same way. Sequencing the genome of cancer biopsies could help guide this prediction; however, not all patients can access this service. Therefore, the new liquid biopsy could help with tracking the progress of cancer therapies.

“This can provide guidance on how to treat oligometastatic disease. For example, if the liquid biopsy indicates that a patient responded well to the early chemotherapy, perhaps they should be offered the possibility of more surgery, which could potentially cure their disease,” said Chaudhuri.

“But if they didn’t respond well, it’s likely the cancer is too widespread and can’t be eradicated with surgery, so those patients should receive more chemotherapy to control their disease.”

While the test’s sensitivity limits meant that tumor DNA was detected more accurately in blood samples than in urine samples, the authors say developments in diagnostic technologies could help bridge this gap.

This study’s findings are a step in the right direction towards a future of customized, personalized treatment regimens for colorectal cancer patients.

“Based on mutations in the blood biopsy, we could identify patients who might benefit from a type of immune therapy called immune checkpoint inhibitors after their initial therapy is complete,” commented Chaudhuri.

“We also found mutations that could be targeted with drugs approved for other cancers. Our current study is observational, but it paves the way for designing future clinical trials that could test some of these potential therapies.”

Sources: JCO Precision Oncology, Washington University in St. Louis.