New diagnostic to reduce physical and financial toxicity brought on by unnecessary chemo treatments

MedTech News: A new test aims to spare thousands of bowel cancer patients from unnecessary chemotherapy.

More than 450 patients and over 20 hospitals from across Australia were involved in the world-first clinical trial, which investigated the blood test as a promising aid to cancer treatment decision-making. 

While most patients with stage II bowel cancer are cured after surgery, the cancer will recur in around 20% of patients. Chemotherapy is currently offered to all stage II colon cancer patients despite a majority not needing it. 

WEHI’s Associate Professor Jeanne Tie and Professor Peter Gibbs collaborated with the Johns Hopkins Kimmel Cancer Centre to develop a novel blood test to identify patients who require chemo after surgery. 

Associate Professor Tie said the DYNAMIC study solved a significant health barrier that has been intensely researched for decades: how experts can decide which patients should be recommended for chemotherapy and which patients can safely avoid the treatment. 

“Our trial has conclusively shown how the ctDNA blood test can be used to direct post-surgical therapy in stage II colon cancer and substantially reduce the number of patients treated with chemotherapy, without impacting the risk of cancer relapse,” Associate Professor Tie said. 

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

The findings are globally significant as previously there was no way of determining whether all the cancer had been removed through colon surgery.

“While chemotherapy can be essential and lifesaving, many patients are receiving the treatment and its associated toxicities without any benefit,” Associate Professor Tie said. 

“This ctDNA blood test could be used to spare around 600 Australians and over 100,000 people worldwide from unnecessary chemo treatments each year.” 

While previous studies have suggested ctDNA measurements could be used to determine the risk of cancer recurrence, the DYNAMIC study is the first randomised study in the world to provide the clinical evidence required to move this from a promising blood test to one that should be routinely used in clinical practice.

Co-lead author Professor Peter Gibbs said the study would not have been possible without the 23 Australian hospitals that enrolled 455 patients for the multi-centre trial since 2015. 

Associate Professor Gibbs said “Randomised studies like this are needed to deliver meaningful patient outcomes, but they are not possible without the support of our collaborators and philanthropic efforts.” 

Victoria’s Western Health hospital contributed the largest number of patients for the trial, while Peter McCallum Cancer Centre was the lead clinical site. 

Researchers hope to demonstrate the value of ctDNA-informed treatment in other stages of colon cancer and other cancer types, including pancreas and ovarian cancer, with three additional randomised studies already underway. 

“Our ctDNA test can be used to reduce the physical and financial toxicity brought on by unnecessary chemo treatments and believe our findings bring us closer to significantly improving treatment options for many patients across a broad range of cancer types,” Professor Gibbs said.