Study: Abdominal Blood Clots May Indicate Undiagnosed Cancer
Published on: June 18, 2015
(WASHINGTON, June 18, 2015) – New research published online today in Blood, the Journal of the American Society of Hematology (ASH), concludes that a blood clot in an abdominal vein may be an
indicator of undiagnosed cancer. The study also suggests that these clots predict
poorer survival in patients with liver and pancreatic cancer.
Compared to the general population,
individuals who develop blood clots in their legs (deep-vein thrombosis, or
DVT) or lungs (pulmonary embolism, or PE) are two to four times more likely to
be diagnosed with cancer within the next year. In the presence of cancer, the
blood can clot more easily. An expanding tumor may compress a vein in its path,
reducing or minimizing blood flow. In other cases, surgery, inflammation, or
tumor growth can injure blood vessels, promoting clotting.
While much is known about the
association between DVT, PE, and subsequent cancer diagnoses, less is known
about how clots in the veins that carry blood through the liver and other
abdominal organs could serve as a marker for cancer. These clots, called
splanchnic venous thrombosis (SVT), are rare and typically only form as the
result of another complication.
To better understand whether SVT could
indicate an undiagnosed cancer, researchers analyzed the medical discharge
diagnoses of more than 1,000 Danish patients diagnosed with the abdominal clots
from 1994-2011. Researchers followed the 1,191 patient records for a median of
1.6 years, calculating their risk of having a subsequent cancer diagnosis compared
to the expected risk in the general population in Denmark. Researchers also
assessed the survival outlook of patients with SVT as compared to cancer
patients without blood clots.
“As we learn more about the
association between many types of thromboses and cancer, we also want to better
understand these more rare clots and how they can perhaps signal a hidden
cancer,” said lead study author Kirstine K.
Søgaard, MD, of Aarhus University Hospital in Aarhus, Denmark. “In this case, we
had access to comprehensive data that we believed could provide insights
useful to clinicians caring for patients with this condition.”
After linking the SVT patient records
to the Danish Cancer Registry, the investigators observed that 183 of the 1,191
patients were later diagnosed with cancer, and more than half (n=95) of these cancers were identified within
three months of SVT diagnosis. The majority of these cancers occurred in the liver,
pancreas, or blood. After comparing cancer incidence among SVT patients with
national Danish cancer rates, investigators estimated that patients with SVT
were 33 times more likely to be diagnosed with cancer than expected during the
first three months following SVT diagnosis.
Seeking to understand how SVT might affect
survival in those patients with cancer, the research team compared survival in
these patients with a matched cohort of cancer patients without the blood clots.
While patients with liver or pancreatic cancer had a poor outcome regardless of
SVT, patients with SVT and these cancers had markedly worse three-month
survival outcomes than cancer patients without the clots (44% v. 55% for
patients with liver cancer, and 33% v. 53% for patients with pancreatic cancer).
While researchers did not observe a significant difference in survival between
blood cancer patients with and without SVT, they noted a higher incidence of
myeloproliferative neoplasms beyond 12 months following SVT diagnosis,
potentially indicating delayed diagnosis.
“This study is the first to
demonstrate in a large population that patients who develop splanchnic venous
thrombosis are likely to be diagnosed with cancer within a relatively short
time period,” said Dr. Søgaard. “As we continue to learn more about patients
who suffer from these blood clots, it will be important to examine the pros and
cons of screening for these hidden cancers.”
Blood (www.bloodjournal.org), the most
cited peer-reviewed publication in the field of hematology, is available weekly
in print and online. Blood is the
official journal of the American Society of Hematology (ASH) (www.hematology.org), the world’s
largest professional society concerned with the causes and treatment of blood
mission is to further the understanding, diagnosis, treatment, and prevention
of disorders affecting blood, bone marrow, and the immunologic, hemostatic, and
vascular systems by promoting research, clinical care, education, training, and
advocacy in hematology.
blood® is a
registered trademark of the American Society of Hematology.
Amanda Szabo, American
Society of Hematology
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