Tumor DNA in blood predicts recurrence of lymphoma

CANCER DIGEST – April 9, 2015 – Patients who have had the most common form of lymphoma might learn if their cancer has returned earlier with a blood test, researchers say.

In a study that followed 126 patients who achieved complete remission of their diffuse large B-cell lymphoma (DLBCL) for many years, researchers found that measuring blood levels of the tumor’s DNA enabled detection of microscopic disease before it could be seen on computerized tomography CT scans.

Led by National Cancer Institute researcher Dr. Wyndham at the Center for Cancer Research, the research team treated the patients with a combination chemotherapy involving etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin, known as EPOCH, and followed them with for a median of 11 years after treatment. The study appeared April 2, 2015, in Lancet Oncology.

Blood samples were collected before treatment, during treatment, and for many years after therapy.  The patients also had CT scans done at the same time as the blood testing as part of standard surveillance. 

Among the 107 patients who achieved complete remission, those who developed detectable circulating tumor DNA during surveillance were over 200 times more likely to have their disease progress than those who did not have detectable tumor DNA circulating in the blood.  

The researchers also found that measuring tumor DNA enabled the detection of cancer recurrence a median of 3.4 months before clinical evidence of disease. In addition, the circulating tumor DNA test was able to predict which patients would not respond to therapy as early as their second cycle of treatment.

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