Extensive screening of patients with blood clots may help detect cancer earlier

September 1, 2008

More extensive screening of patients with unexplained blood clots could increase the rate of cancer detection among these patients by 21 per cent, according to a research analysis published in the September 2, 2008 issue of Annals of Internal Medicine.

Dr. Marc Carrier and Dr. Marc Rodger of Ottawa made the finding after pooling data from nearly 10,000 patients from 34 studies. They found that the routinely used basic cancer screening strategy only detects 49 per cent of cancers, while an extensive screen that includes a CT scan of the abdomen and pelvis detects 70 per cent. They are currently testing a modified CT scanning procedure than may increase the rate of detection even further.

It has long been known that blood clots in the legs, arms and lungs (called venous thromboembolism) can be an early sign of an underlying cancer. The systematic review and meta-analysis published in Annals is the largest and most comprehensive examination of cancer screening in this group of patients. Venous thromboembolism affects up to five per cent of people in their lifetime. Up to 10 per cent of these patients will be diagnosed with cancer in the year following the venous thromboembolism.

“To treat cancer effectively, it is essential that we detect it as early as possible and our analysis shows that CT scanning may help us do this in this high-risk group of patients,” said Dr. Marc Carrier, an Associate Scientist at the Ottawa Hospital Research Institute, Hematologist at The Ottawa Hospital and Assistant Professor of Medicine at the University of Ottawa. “We’re now piloting an extensive screening strategy at The Ottawa Hospital and we have been able to detect a number of cases of cancer much earlier than we would have otherwise been able to. We need further research to confirm and validate the results, but it is promising.”

“The potential impact of this research is great, but we also need to look at the cost-effectiveness of extensive screening and possible complications for patients,” said Dr. Marc Rodger, a Senior Scientist at the Ottawa Hospital Research Institute, Hematologist at The Ottawa Hospital and Associate Professor of Medicine the University of Ottawa. “Anyone worried about blood clots and the risk of cancer should speak with their doctor.”

This study was funded by the Canadian Institutes of Health Research.

About the Ottawa Hospital Research Institute
The Ottawa Hospital Research Institute (OHRI) is the research arm of The Ottawa Hospital and is an affiliated institute of the University of Ottawa, closely associated with the University’s Faculties of Medicine and Health Sciences. The OHRI includes more than 1,300 scientists, clinical investigators, graduate students, postdoctoral fellows, and staff conducting research to improve the understanding, prevention, diagnosis and treatment of human disease.

Media contact
Jennifer Paterson
Director, Communications and Public Relations
Ottawa Hospital Research Institute
613-798-5555 x 19691