Conference Coverage

Rivaroxaban bonus: Early unmasking of occult GI cancers

 

Key clinical point: GI bleeding in patients on rivaroxaban may represent unmasking of an occult GI cancer.

Major finding: Among patients on rivaroxaban, 1 in 12 GI bleeding events was associated with an occult GI cancer.

Study details: This was a secondary analysis looking at cancers in COMPASS, a randomized trial of more than 27,000 patients on rivaroxaban and/or aspirin for vascular prevention.

Disclosures: The presenter reported receiving research grants from Bayer, which sponsored the COMPASS trial.


 

REPORTING FROM THE ESC CONGRESS 2018

– The increased risk of major GI bleeding documented with dual-antiplatelet therapy using rivaroxaban and aspirin when compared with aspirin alone for vascular protection in the previously reported massive COMPASS trial may turn out to be a blessing in disguise.

Dr. John W. Eikelboom, a hematologist at McMaster University in Hamilton, Ont. Bruce Jancin/MDedge News

Dr. John W. Eikelboom

That’s because a new secondary analysis of COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies), a randomized trial that included 27,395 patients with stable coronary or peripheral artery disease followed for a mean of 23 months at more than 600 centers in 33 countries, identified a strong association between early bleeding in rivaroxaban-treated patients and subsequent early diagnosis of new GI cancer. Ditto for rivaroxaban-associated genitourinary bleeding and subsequent GU cancer.

“Among COMPASS patients with vascular disease receiving long-term antithrombotic therapy, more than 1 in 5 new diagnoses of cancer are preceded by bleeding. GI and GU bleeding are powerful and relatively specific predictors of new GI and GU cancer diagnoses, respectively, and more than 75% of these cancers diagnosed after bleeding are diagnosed within 6 months of the bleed,” John W. Eikelboom, MD, reported at the annual congress of the European Society of Cardiology.

These findings strongly suggest that rivaroxaban (Xarelto), a direct-acting oral anticoagulant (DOAC), may be unmasking occult GI and GU cancers earlier than the malignancies would otherwise have declared themselves.

“Although overall cancer rates were similar in the three treatment groups [rivaroxaban at 2.5 mg twice daily plus aspirin at 100 mg/day, rivaroxaban monotherapy at 5 mg twice daily, or aspirin alone at 100 mg/day], the early increase in GI bleeding with rivaroxaban-based therapy resulted in earlier diagnosis of GI cancer in these patients. By reducing major cardiovascular events and mortality, the combination of rivaroxaban and aspirin already produces a clear net benefit, and by unmasking GI cancers at an earlier stage, the combination could potentially lead to the added benefit of improved GI cancer outcomes,” commented Dr. Eikelboom, a hematologist at McMaster University in Hamilton, Ont., and lead investigator of the previously published COMPASS trial (N Engl J Med. 2017 Oct 5;377[14]:1319-30).

This possibility that unmasking of occult GI cancer might result in improved survival deserves to be a high research priority in light of the enormous death toll caused by colorectal cancer. Planned longer-term follow-up of the COMPASS participants should be helpful in this regard, he added.

This new COMPASS finding effectively makes a silk purse out of a sow’s ear. When the primary outcomes of COMPASS were announced, many physicians reasoned that if the other commercially available DOACs also outperform warfarin but don’t pose a significantly increased threat of serious bleeding events, why not preferentially turn to them rather than rivaroxaban in patients with high HAS-BLED scores? But now rivaroxaban’s increased GI bleeding risk has begun to look like a potentially important advantage.

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