A recent retrospective study evaluating the non-vitamin K antagonist oral anticoagulants (NOACs) including apixiban, dabigatran, and rivaroxaban in GI cancer detection was performed by Clemens and colleages.1

Patients receiving NOACs had GI bleeding rates of ranging from 1.42% to 3.52%, however each individual agent had higher GI bleeding rates when compared with warfarin. This difference may be due to the relatively higher absorption of warfarin and lack of anticoagulant effects within the lumen of the GI tract.3

The NOACs also have a lower bioavailability compared with warfarin, leading to higher intraluminal concentrations and direct contact with GI lesions.3


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The incidence of GI cancer ranged from 0.61% to 0.83% which was again higher than the incidence in the warfarin patients (0.37% to 0.73%).1

Patients who are started on one of the newer NOAC agents may be more likely to receive an endoscopic evaluation and subsequent new GI malignancy diagnosis based on their relatively higher GI bleeding rate compared with warfarin in addition to the relative inexperience with the newer agents.

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An alternate explanation may be that the newer NOAC agents predispose patients to GI malignancies, however there is no preclinical or clinical trial data to support this.4,5,6

Patients who are taking antiplatelets and/or anticoagulants should be closely monitored for potential GI bleeding, especially within the first year of initiation of the medications.

Although GI bleeding from a benign source is a more common explanation, the possibility of a malignant lesion within the GI tract should be kept on the differential diagnosis.

References

  1. Clemens A, Strack A, Noack H, et al. Anticoagulant-related gastrointestinal bleeding–could this facilitate early detection of benign or malignant gastrointestinal lesions? Ann Med. 2014;46(8):672-678.
  2. Asiimwe A, Li JJ, Weerakkody G, et al. Diagnoses of gastrointestinal cancers after gastrointestinal bleeding in patients receiving clopidogrel or warfarin. Curr Drug Saf. 2013;8(4):261-269.
  3. Desai J, Granger CB, Weitz JI, Aisenberg J. Novel oral anticoagulants in gastroenterology practice. Gastrointest Endosc. 2013;78(2):227-239.
  4. ELIQUIS (apixaban) Package Insert. Princeton, NJ; Bristol-Myers Squibb Company. http://packageinserts.bms.com/pi/pi_eliquis.pdf.
  5. PRADAZA (dabigatran etexilate mesylate) Package Insert. Ridgefield, CT; Boehringer Ingelheim Pharmaceuticals, Inc. http://bidocs.boehringer-ingelheim.com/BIWebAccess/ViewServlet.ser?docBase=renetnt&folderPath=/Prescribing%20Information/PIs/Pradaxa/Pradaxa.pdf.
  6. XARELTO (rivaroxaban) Package Insert. Gurabo, PR; Janssen Ortho, LLC.  http://www.xareltohcp.com/sites/default/files/pdf/xarelto_0.pdf.