CDK4 and bone metastasis: Treatment with CDK4/6 inhibitors plus ET was associated with improved OS both for the visceral metastasis subgroup (HR, 1.31; 95% CI, 1.12-1.53; P < .001), with low heterogeneity across studies (I2 = 0%; P = .69), and for the bone-only metastasis subgroup (HR, 1.22; 95% CI, 0.88-1.68; P < .001), with low heterogeneity across studies (I2 = 0%; P = .45) (eFigure 4 in the Supplement).