MedicalResearch.com Interview with:
Jeanne Tie MBChB, FRACP, MD
Division of Systems Biology and Personalised Medicine, Walter and Eliza Hall Institute of Medical Research
Department of Medical Oncology, Western Health, St Albans, Victoria, Australia.
Department of Medical Oncology,
Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne
Parkville, Victoria, Australia
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: This study investigated the ability of circulating tumor DNA (ctDNA) in detecting residual microscopic cancer after surgery with curative intent in patients with stage II colon cancer. Although the majority of patients with stage II colon cancer are cured by surgery alone, our ability to accurately predict the risk of cancer relapse based on current clinical and pathological criteria is imprecise. Population-based study indicated that adjuvant chemotherapy is given to up to 40% of stage II colon cancer patients, meaning that we are over-treating a significant number of patients with cytotoxic therapy. A better indicator of residual disease and recurrence would be very useful clinically.
The current study collected tumor and blood samples from 230 patients with stage II colorectal cancer. A personalised assay was then designed to detect patient-specific tumor DNA in the plasma samples collected four to ten weeks after surgery. The presence of ctDNA (positive test) in the post-operative blood sample predicted recurrence in 100% of patients, while the relapse rate is only 10% in those with negative ctDNA test. We have also shown that the ctDNA test is a better predictor of recurrence than the standard clinic-pathological criteria.
MedicalResearch.com: What should readers take away from your report?
Response: The presence of ctDNA after potentially curative surgery is a direct indicator of residual microscopic cancer and predicts for subsequent clinical relapse.
MedicalResearch.com: What recommendations do you have for future research as a result of this study?
Response: This study highlights the promising role of ctDNA as a marker of minimal residual disease in early stage cancer. The next step would to demonstrate the clinical utility of this test in a randomised study, that is to show that using this test can lead to better patient outcomes such as reducing chemotherapy usage or improving survival.
MedicalResearch.com: Is there anything else you would like to add?
Response: In patients who were treated with adjuvant chemotherapy, we also collected blood samples during and after treatment. Data from the small number of patients suggest that serial ctDNA results could reflect the effectiveness of treatment in real time. For example, the two patients where the initial post-operative positive ctDNA remained detectable after completion of chemotherapy have both experienced disease relapse.
MedicalResearch.com: Thank you for your contribution to the MedicalResearch.com community.
J. Tie, Y. Wang, C. Tomasetti, L. Li, S. Springer, I. Kinde, N. Silliman, M. Tacey, H.-L. Wong, M. Christie, S. Kosmider, I. Skinner, R. Wong, M. Steel, B. Tran, J. Desai, I. Jones, A. Haydon, T. Hayes, T. J. Price, R. L. Strausberg, L. A. Diaz, N. Papadopoulos, K. W. Kinzler, B. Vogelstein, P. Gibbs.
Circulating tumor DNA analysis detects minimal residual disease and predicts recurrence in patients with stage II colon cancer. Science Translational Medicine, 2016; 8 (346): 346ra92 DOI: 10.1126/scitranslmed.aaf6219
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