Table 2. Incidence of thromboembolic events with aromatase inhibitors and comparators.

	Thromboembolic events (% of patients)
Reference	Aromatase inhibitor	Comparator	P-value
ATAC (2002)	Anastrozole 64 (2.1%)	Tamoxifen 109 (3.5%)	=0.0006
Coombes et al (2004) (IES Trial)	Exemestane 30 (1.3%)	Tamoxifen 55 (2.4%)	=0.007
Dombernowsky et al (1998)	Letrozole (2.5 mg) 1 (0%)	Megestrol acetate 15 (7.9%)	Unknown
	Letrozole (0.5 mg) 2 (1%)
Goss et al (2003) (MA-17 trial) (cardiovascular events)	Letrozole (2.5 mg) 88 (4.1%)	Placebo 77 (3.6%)	=0.4