Table 2.

Associations between ESR1 single nucleotide polymorphism rs9322336 and toxicity-related treatment discontinuation using a recessive statistical model.

Drug	Reason for discontinuation	Genotype	Number patients discontinued AI/total with genotype	HR (95% CI)	P value
Both AIs	Any toxicity	All combined	141/396 (35.6%)	2.4 (1.3–4.5)	0.005
		TT	82/241 (34.0%)
		TC	48/137 (35.0%)
		CC	11/18 (61.1%)
	AIMSS	All combined	107/396 (27.0%)	3.0 (1.6–5.7)	0.001
		TT	63/241 (26.1%)
		TC	34/137 (24.8%)
		CC	10/18 (55.6%)
Letrozole	Any toxicity	All combined	63/198 (31.8%)	1.5 (0.5–4.1)	0.44
		TT	39/121 (32.2%)
		TC	20/68 (29.4%)
		CC	4/9 (44.4%)
	AIMSS	All combined	48/198 (24.2%)	2.0 (0.7–5.6)	0.18
		TT	30/121 (24.8%)
		TC	14/68 (20.6%)
		CC	4/9 (44.4%)
Exemestane	Any toxicity	All combined	78/198 (39.4%)	4.2 (1.9–9.2)	0.0003
		TT	43/120 (35.8%)
		TC	28/69 (40.6%)
		CC	7/9 (77.8%)
	AIMSS	All combined	59/198 (29.8%)	5.0 (2.1–11.8)	0.0002
		TT	33/120 (27.5%)
		TC	20/69 (29.0%)
		CC	6/9 (66.7%)

Number of patients in total cohort or divided by aromatase inhibitor (AI) who discontinued therapy because of toxicity is given by genotype. Hazard ratios (HR) and corresponding p values are given for both aromatase inhibitors (AI) combined and for each AI individually. AIMSS: AI-associated musculoskeletal syndrome; CI: confidence interval.