New blood test could spare patients from unnecessary chemotherapy

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Researchers have developed a new blood test that could revolutionise how chemotherapy is used for colon cancer by identifying the patients that need chemo and those that can be safely spared treatment. 

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

Most patients with stage 2 colon cancer are cured after surgery to remove the cancer from the bowel but the cancer will recur in around 20 per cent of patients. 

Chemotherapy is currently offered to all stage 2 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 in the US to develop a novel blood test to identify patients who require chemotherapy after surgery. 

The novel blood test, co-developed by WEHI, can detect invisible cells that release tiny amounts of circulating tumour DNA (ctDNA) into the bloodstream, enabling researchers to identify which patients should be offered chemotherapy based on whether micrometastases have been detected. 

Associate Professor Jeanne Tie said, “Our trial has conclusively shown how the ctDNAblood 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.

“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.” 

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

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