A large clinical trial is underway on an exciting new blood test designed to help doctors determine whether a patient needs to undergo chemotherapy following surgery to remove cancerous tumors.

The blood test is called a circulating tumor DNA test (ctDNA), and is designed to identify fragments of tumor DNA. The test was developed in an international collaboration between scientists in the United States and Australia, and early trials have demonstrated extraordinary success in allowing doctors to accurately identify patients most likely to suffer a cancer relapse following surgery.

The new trial taking place at more than 40 hospitals in Australia and New Zealand is focused on the association between ctDNA levels found in blood after cancer surgery and the risk of relapse. The hope is that the trial will be able to clearly identify what amount of ctDNA can be correlated with a high risk of relapse. If all goes well, the trial will lead to an effective blood test that can reduce the volume of unnecessary chemotherapy treatments patients must undergo.

"While chemotherapy is an essential, life-saving treatment, we don't want patients receiving it if they don't need it," says Jeanne Tie, a researcher working on the project. "We want to help these patients avoid serious and ongoing side-effects associated with chemotherapy."

The blood test was originally – and successfully – used to identify early stage bowel cancer patients, but more recently its use has been expanded to include ovarian cancer. The new trial will focus on both bowel cancer and ovarian cancer patients who have undergone surgery to remove tumors following either stage 2 or stage 3 diagnoses.

"We suspect that many women with early stage ovarian cancer can be treated with surgery alone, but we currently treat all these patients as though their cancer may recur, with high dose chemotherapy," explains Sumi Amanda, leading the ovarian cancer arm of the new trial.

The trials are set to run until around 2021, and if they prove successful will offer clinicians a valuable new diagnostic tool in personalizing cancer treatments for patients, as well as reducing unnecessary and aggressive chemotherapy doses.

Watch the researchers outline this new trial in the video below.

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