Ovarian cancers have one of the highest mortality rates, ranking fifth in cancer deaths among women. Of the 22,000 new estimated cases of ovarian cancer this year, only 10-15 percent of patients will be successfully treated. Unfortunately, in the large percent of remaining patients, the cancer doesn’t respond to treatment, or will inevitably return with a vengeance.
Now researchers at the Mayo Clinic say a new non-invasive test could predict whether the cancer is likely to return years before it compromises the survival of the patients. This diagnostic test could transform how doctors monitor and preemptively treat ovarian cancer to increase patient outcome.
The diagnostic test for ovarian cancer relapse relies on measuring the amount of tumor DNA in the blood – a process known as a liquid biopsy. Circulating tumor DNA (ctDNA), also known as cell-free tumor DNA, is genetic material from the tumor that’s freely floating in the bloodstream of cancer patients. ctDNA represents a non-invasive cancer biomarker that can indicate the presence of disease.
In this case, the research team asked whether ctDNA can predict the recurrence of a disease. They sampled blood from 10 patients with ovarian cancer before and after surgery. They also collected DNA from the actual tumor that was removed during surgery. Using mate-pair sequencing, the team showed that patients whose post-surgery blood have DNA matching that of the tumor were more likely to have cancer relapse. By contrast, patients whose post-surgery blood DNA didn’t align with the tumor DNA were more likely to be in remission.
"With liquid biopsies, we don't have to wait for tumor growth to get a DNA sample," said George Vasmatzis, researcher at the Mayo Clinic Center for Individualized Medicine, and senior author of the study. "This important discovery makes it possible for us detect recurrence of the disease earlier than other diagnostic methods. We can repeat liquid biopsies to monitor the progression of the cancer. That gives hope of a better treatment plan over time."
Advantages of this test could be multifold. First, sequencing the tumor identifies specific mutations that could define which treatment option would be best for patients. Second, that the test can predict cancer recurrence will allow doctors to monitor and treat the cancer preemptively, leading to more positive survival outcomes. And considering that the median survival for recurrent ovarian cancer is only 1-2 years, every effort counts.
Additional source: Mayo Clinic press release