Toward predicting colorectal cancer recurrence: the α-CORRECT study of circulating tumor DNA - a plain language summary of the original publication.

What is this summary about? This summary describes the α-CORRECT study and its key results. The study evaluated a new blood test that looks for tiny traces of cancer in patients with stage III colorectal cancer after treatment. What is the purpose of this plain language summary? The purpose of this plain language summary is to help readers understand the main findings of the α-CORRECT study. Why was this study done? Colorectal cancer is a leading cause of cancer death. Many patients with stage III colorectal cancer are treated with surgery to remove the tumor, followed by chemotherapy to kill any remaining cancer cells. However, some cancer cells may stay in the body after surgery and chemotherapy, and potentially grow, causing cancer recurrence - when cancer returns with tumors and/or symptoms, even years later. Patients with traces of cancer remaining in the body after standard treatment have what is called molecular residual disease (MRD). Because only a few cancer cells remain, the signs of disease (such as symptoms or abnormal physical exam findings) are typically absent, and even imaging methods like computed tomography (CT) or Positron Emission Tomography (PET) may not detect the cancer. However, the presence of these cancer cells can sometimes be detected by a new type of MRD test that looks for fragments of tumor genetic material - circulating tumor DNA (ctDNA) - that cancer cells release into the blood. The α-CORRECT study was designed to find out whether a new MRD test that looks for ctDNA in the blood could detect the presence of cancer cells in the body after treatment, and how well detection of ctDNA predicted cancer return. What did the study show? The study showed that the new MRD test can accurately predict the likelihood of cancer return after treatment. The chances of cancer returning were about 10 times higher for a person with MRD detected after surgery and about 50 times higher for a person with MRD detected during the follow-up (surveillance) period than for a person with no MRD detected. During the follow-up period, the MRD test detected ctDNA about 10 months before cancer was found by symptoms or by imaging methods. In other words, the new blood test warned doctors about cancer returning many months earlier than usual tests. Why is this study important? Finding evidence of MRD can help predict the likelihood of cancer return and may help doctors decide who needs more treatment and who may safely avoid additional chemotherapy: Patients with ctDNA detected (meaning MRD is present and the risk of cancer recurrence is high) may be candidates to receive additional treatment, which may improve their survival.Patients with no ctDNA detected (meaning MRD is likely absent, and the risk of cancer recurrence is low) may not require chemotherapy, helping them to avoid side effects and costs from treatment that may not provide benefit. The α-CORRECT study was not meant to set exact MRD levels for changing treatment. Other ongoing clinical studies are looking at how MRD test results should be used to make better treatment decisions.