The blood test finds remnants of cancer DNA in the blood stream in order to inform decisions about whether a patient needs chemotherapy after surgery.
A diagnosis of cancer can be terrifying—but sometimes the treatments themselves can be just as frightening for patients. Surgery, chemotherapy, radiation therapy, and immunotherapy can be daunting and some of the side effects from these life-saving technologies can be life-changing.
Chemotherapy is still the mainstay of most cancer treatment and has saved countless lives—but the new test is a step toward identifying when chemotherapy may not be necessary. Finding and measuring cancer DNA in patient’s blood could revolutionize cancer care, according to a new study.
The blood test is currently in clinical trials at more than 40 hospitals in Australia and New Zealand—making it one of the largest trials both in Australia and around the world that’s investigating a predictive blood test to guide cancer treatment.
PREVENTING CANCER’S RETURN
For the study, which appears in Gut, researchers were specifically investigating bowel cancer. At the time of diagnosis, many early stage bowel cancer patients have tumors that appear to be limited to the bowel, with no evidence they have spread to elsewhere in the body.
But, following successful surgery to remove the cancer, around a third of these patients get a recurrence elsewhere in the body in later years. That means the cancer cells had already spread at the time of diagnosis, but couldn’t be detected using current standard blood tests and scans.
If these patients had received treatment with chemotherapy after surgery to eradicate microscopic residual cancer cells responsible for the cancer’s return, it would have prevented about a third of relapses.
Currently, doctors base their decision to use chemotherapy on pathological assessment of the bowel cancer removed at the time of surgery.
For example, the discovery of cancer cells in the lymph glands next to the bowel (known as a Stage III cancer) means there is an increased probability that the cancer has already spread.
But while pathology information is useful, it lacks precision. Some high-risk patients won’t have cancer recurrence because surgery alone has cured their cancer, while other apparently low-risk patients will suffer recurrence.
This lack of ability to accurately determine who has microscopic disease and is most at risk of relapse means that many patients currently get treatment with six months of chemotherapy.
This means dealing with the sometimes tough side effects of chemotherapy, even though they may not need to have the treatment. Meanwhile, other patients that would potentially benefit don’t receive the necessary chemotherapy, because they appear to be at low risk.
|Read on: Blood test spots microscopic cancer to predict relapse risk|