HONOLULU – During the first month after a new cancer diagnosis, patients face a substantially elevated risk for an arterial thromboembolic event – an MI or stroke – consistent with the well-described increased risk newly diagnosed cancer patients face from venous thromboembolism, based on findings from a prospective study of more than 4,000 people.
In the new study, 836 patients newly diagnosed with cancer had a 480% increased rate of a fatal or nonfatal MI or stroke during the 30 days following their diagnosis, compared with 3,339 matched people without cancer and after adjustment for baseline differences in demographics and cardiovascular risk factors, Babak B. Navi, MD, said while presenting a poster at the International Stroke Conference sponsored by the American Heart Association.
An additional analysis that focused on 210 of the 836 patients with incident cancer who had any of seven of the cancers known to pose the highest venous thromboembolism risk (lymphoma; gynecologic cancer; or cancer of the pancreas, stomach, lung, bladder, or testes) showed an 1,750% greater rate of incident MI or stroke during the first 30 days after diagnosis, compared with matched people without cancer, reported Dr. Navi, chief of the stroke and hospital neurology at Weill Cornell Medicine, New York.
In contrast, during both the period 1-3 months after the cancer diagnosis and more than 3 months after, the rate of MI or stroke among recently diagnosed cancer patients was not significantly different from the rate in comparator individuals, although the data showed modest trends toward more arterial thromboembolic events after a month, and the lack of statistically significant differences may have been a power issue, Dr. Navi suggested.
Mitchel L. Zoler/MDedge News
Dr. Babak B. Navi
The reasons for this acutely increased risk for arterial thromboembolic events, as well as the early spike in venous thromboembolic events, are not completely clear, but they likely result from factors released by tumors, effects from the drugs that patients receive for cancer treatment, stress, and interruption of antithrombotic treatment. Dr. Navi fingered cancer-induced hypercoagulability as likely the biggest culprit. It may now be reasonable to test the idea of treating newly diagnosed cancer patients with agents that could reduce their risk for MI or stroke, such as aspirin or a statin, he said in an interview.
The new analysis used data collected in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study, which during 2003-2007 enrolled more than 30,000 U.S. residents who were at least 45 years old. Dr. Navi and his associates used data collected from all REGARDS participants who developed incident cancer and had continuous Medicare coverage for at least 1 year before entering REGARDS, excluding those with cancer before enrollment. They used the Medicare records to identify the cancer diagnoses, and matched each of these people with four similar but cancer-free people enrolled in the study. Follow-up continued through September 2015. The average age of this REGARDS subgroup at enrollment was 72 years old, and nearly half were women. The incident cancers included 640 patients with a solid tumor, 71 with hematologic cancers, 13 with brain tumors, and 112 with an unknown primary cancer site.
Dr. Navi and his associates designed this study to validate previously reported findings of increased arterial thromboembolic events in newly diagnosed cancer patients from studies of insurance claims databases. Although the increased risk for venous thromboembolism in cancer patients is already well established, documenting a similar risk for arterial events is important because they are “generally more impactful for patients than venous thromboembolism,” Dr. Navi said.
REGARDS has received no commercial funding. Dr. Navi reported no disclosures.
SOURCE: Navi BB et al. Stroke. 2019 Feb;50(Suppl_1): Abstract WMP53.