Landmark test sparks hope for thousands of colon cancer patients

Landmark test sparks hope for thousands of colon cancer patients

Illuminate newsletter header, Spring 22
September 2022
Researchers have shown for the first time that a blood test can identify colon cancer patients who need chemotherapy after surgery and those that can be safely spared.

The DYNAMIC study is the first to use circulating tumour DNA (ctDNA) to precisely predict whether a patient should have chemotherapy following surgery to remove their cancer. Use of the ctDNA test, co-dveloped by WEHI and the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins University in the US, could save hundreds of thousands of colon cancer patients worldwide from undergoing chemotherapy unnecessarily.

Revolutionising treatment


Above: Researchers discover tumour DNA fragments
like this can direct post- surgical therapy in colon
cancer patients. Credit: Drew Berry, WEHI.TV

Chemotherapy is currently offered to all patients with stage II colon cancer after surgery, despite the majority not needing it.

Its goal is to eradicate micrometastases – cancer cells that have travelled from the original tumour in the bowel via the bloodstream to seed at another site.

In their early stages, these deposits of cancer cells are minuscule and can’t be seen at surgery or on radiological images.

However, these invisible cells release tiny but detectable amounts of ctDNA into the bloodstream.

WEHI’s Associate Professor Jeanne Tie said the blood test enabled researchers to identify which patients required chemotherapy based on whether micrometastases were present.

“We found that when a patient’s blood test does not reveal ctDNA after colon surgery, chemotherapy can be avoided as there are no tumour fragments left to kill and the likelihood of micrometastases is very low,” Associate Professor Tie said.

“By proving ctDNA can be used to direct post-surgical therapy in these patients, we have overcome a significant health barrier and can substantially reduce the number of patients unnecessarily given chemotherapy.”

Collaborative effort

Co-lead author Professor Peter Gibbs said the success of the test in guiding post-surgery cancer treatment could not have been proven without the 23 Australian hospitals that enrolled 455 patients in the clinical trial, beginning in 2015.

“These hospitals were critical for us to complete this study, the first randomised trial in any solid tumour type worldwide that used a blood test to determine which patients can safely forgo chemotherapy after surgery,” Professor Gibbs said.

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