Circulating Tumor DNA Blood Test May Aid Detection

Study looks back at recurrence of diffuse large-B-cell lymphoma


What is ctDNA? Liquid Biopsy?

When cells die, including cancer cells, some of their DNA ends up in the blood. Such DNA from dead cancer cells is called circulating tumor DNA, or ctCNA. In the case of DLBCL and other cancers, scientists have developed tests to detect this circulating DNA. This kind of approach is sometimes referred to as a “liquid biopsy,” and investigators point to potential benefits for monitoring disease, as well as predicting a person's response to therapy early on.

Circulating Tumor DNA Study

In a recently published study, investigators at the National Cancer Institute analyzed blood from 126 people with DLBCL for the presence of circulating tumor DNA. Diffuse large-B-cell lymphoma, or DLBCL, is the most common type of lymphoma, a blood cancer that begins in certain cells of the immune system.

Despite having a similar appearance under the microscope, different subsets of DLBCL can have different prognoses. According to the American Cancer Society, overall, about three out of four people will have no signs of disease after the initial treatment, and many are cured with therapy.

The cancer recurs in up to 40 percent of people, however, and it is then often incurable, especially when it comes back early and/or when levels of tumor cells in their blood are high, according to the National Cancer Institute.

Everyone in the present investigation had received treatment for DLBCL according to 3 different protocols, with drugs such as etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin, known as EPOCH, with or without rituximab, in clinical trials between May 1993 and December 2013.

Blood testing was done before each chemotherapy cycle, at the end of treatment, and every time staging was assessed. People were followed for many years after therapy, and CT scans were done at the same time as the blood testing. People in this study were followed for a median of 11 years after treatment -- that is, the middle number in the series was 11 years, but people were followed for both shorter and longer periods.

Blood Test Predicted Progression, Recurrence

Of the 107 people who had a complete remission of the cancer, those who developed detectable ctDNA in the blood samples were over 200 times more likely to have their disease progress than those who did not have detectable ctDNA.

The blood test was able to predict which people would not respond to therapy as early as the second cycle of anti-cancer treatment.

The blood test also enabled the detection of cancer recurrence a median of 3.4 months before there was any clinical evidence of disease, in advance of detection via CT scan.


Roschewski M, et al. Circulating tumour DNA and CT monitoring in patients with untreated diffuse large B-cell lymphoma: a correlative biomarker study. Lancet Oncology.

Circulating tumor DNA in blood can predict recurrence of the most common type of lymphoma. Accessed April 2015.

B-cell lymphomas.

Diffuse large B-cell lymphoma. Accessed April 2015.

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