The quality of evidence is downgraded by imprecise results (few outcome events and wide confidence intervals).
A Cochrane review [Abstract] 1 included 10 studies with a total of 2 934 subjects to evaluate the efficacy and safety of oral anticoagulants in ambulatory people with cancer undergoing chemotherapy, targeted therapy, immunotherapy, or radiotherapy (either alone or in combination), with no standard therapeutic or prophylactic indication for anticoagulation. The oral anticoagulant was warfarin in 6 studies, and a direct oral anticoagulant (DOAC) in 4 studies (apixaban in 3 studies, and rivaroxaban in 1 study). The comparator was either placebo or no prophylaxis.
Compared to no prophylaxis, warfarin did not reduce statistically dignificantly mortality at 6 months (RR 0.93, 95% CI 0.77 to 1.13; 3 studies, n=946), and at 12 months (RR 0.95, 95% CI 0.87 to 1.03; 5 studies, n=1 281). One study assessed the effect of warfarin compared to no prophylaxis on thrombosis; no difference was observed for pulmonary embolism (RR 1.05, 95% CI 0.07 to 16.58; 1 study, n=311), and for symptomatic DVT (RR 0.08, 95% CI 0.01 to 1.42; 1 study, n=311). Warfarin increased major (RR 2.93, 95% CI 1.86 to 4.62; RD 107 more per 1000, 95% CI 48 more to 201 more; 5 studies, n=1 281) and minor bleeding (RR 3.14, 95% CI 1.85 to 5.32; RD 167 more per 1000, 95% CI 66 more to 337 more; 4 studies, n=863) at 12 months.
Compared to no prophylaxis, at 3 to 6 months, DOACs did not reduce statistically significantly mortality (RR 0.94, 95% CI 0.64 to 1.38; 3 studies, n=1 440) or symptomatic DVT (RR 0.58, 95% CI 0.30 to 1.15; 3 studies, n=1 440), but reduced the risk of pulmonary embolism slightly compared to no prophylaxis (RR 0.48, 95% CI 0.24 to 0.98; RD 24 fewer per 1000, 95% CI 35 fewer to 1 fewer; 3 studies, n=1 440). No statistically significant increases in major bleeding (RR 1.65, 95% CI 0.72 to 3.80; 3 studies, n=1 440), and minor bleeding (RR 3.58, 95% CI 0.55 to 23.44; 3 studies, n=1 440) were observed.
Primary/Secondary Keywords