As previously reported, COMPASS participants on rivaroxaban plus aspirin had a 3.1% major bleeding rate as defined according to modified International Society on Thrombosis and Hemostasis criteria, for a statistically significant 70% increase in risk, compared with the 1.9% rate in patients on aspirin alone. Rivaroxaban monotherapy also was associated with increased bleeding risk. Of note, most of the excess in bleeding involved GI bleeding, and it was front-loaded during the first year of the trial. Also, reassuringly, there was no increased incidence of intracranial or fatal bleeding in patients on rivaroxaban.
A total of 1,082 patients were diagnosed with a new cancer during 23 months of follow-up. Nearly a quarter (23%) of the new GI cancers and 45% of the new GU cancers were diagnosed after bleeding from those sites.
The incidence of GI cancer diagnosed after GI bleeding was 7.8%, whereas patients with no prior GI bleeding had a mere 0.9% rate of newly diagnosed GI cancer during the study period. Thus, roughly 1 out of every 12 cases of GI bleeding was associated with diagnosis of a new GI cancer, and GI bleeding was associated with a 13-fold increased risk of subsequent GI cancer diagnosis. Put another way, the number of cases of GI bleeding occurring in patients on rivaroxaban that needed to be investigated in order to find one new GI cancer was 12.
Similarly, 13% of COMPASS participants who developed GU bleeding were subsequently diagnosed with a new GU cancer, compared with just 0.3% of subjects without GU bleeding. That translates into an 83.4-fold increased risk of GU cancer in patients with GU bleeding.
