Table 2 Clinical studies of aromatase inhibitors and cognitive function
From: Do aromatase inhibitors have adverse effects on cognitive function?
| Â | Â | Â | Â | Â | Â | Powera | Â | |
|---|---|---|---|---|---|---|---|---|
Study | Study design | Timing of measures | Number at baseline | Number at last follow-up | Treatment comparison | ES = 0.50 | ES = 0.35 | Conclusions |
IBIS II [28] | RCT | Pre-Rx, at 6 months on Rx, and at 2 years on Rx | 227 | 151 | Anastrozole Placebo | 94% (6-month analysis), 87% (2-year analysis) | 71% (6-month analysis), 58% (2-year analysis) | No statistically significant difference in cognitive function between arms was observed. |
TEAM [29] | RCT and control group | Pre-Rx and at 1 year on Rx | 179 + 120 healthy controls | 179 + 120 | Exemestane Tamoxifen (→ exemestane) | 93% (tamoxifen compared with exemestane), 93% (tamoxifen compared with control), 96% (exemestane compared with control) | 67% (tamoxifen compared with exemestane), 68/% (tamoxifen compared with control), 73% (exemestane compared with control) | No statistically significant effect of exemestane on cognition was observed; tamoxifen was associated with worse verbal memory, executive function, and information-processing speed |
RCT | At 5 years on Rx and 1 year after ceasing Rx | 120 | 100 | Tamoxifen or letrozole → tamoxifen Letrozole or tamoxifen → letrozole | 78% | 48% | Overall cognitive function was significantly better in patients taking letrozole rather than tamoxifen at year 5. Significant improvement in cognition after completion of endocrine therapy was observed. | |
ATAC [26] | Crosssectional | At 1 to 5 years on Rx (mean of 3 years) | 94 + 35 healthy controls | N/A | Anastrozole or tamoxifen (combined) Untreated | 71% | 42% | Endocrine therapy users had worse verbal memory and processing speed compared with untreated controls |
Bender, et al. [27] | Crosssectional, nonrandomized | At >3 months on Rx | 31 | N/A | Anastrozole Tamoxifen | 28% | 16% | Poorer verbal and visual learning in patients taking anastrozole compared with patients taking tamoxifen was observed. |
Collins, et al. [31] | Nonrandomized | Around start of Rx and at 5 to 6 months on Rx | 45 + 28 healthy controls | 'Attrition <10% in all groups' | Anastrozole Tamoxifen | 48% (tamoxifen), 33% (anastrozole) | 27% (tamoxifen), 19% (anastrazole) | No significant difference between treatments, relative to healthy controls, was observed. |
Hermelink, et al. [30] | Nonrandomized | Before start of CT, before final cycle of CT, and at 1 year (after baseline) | 101 | 92 | Anastrozole or letrozole Tamoxifen | 61% | 35% | No statistically significant difference between tamoxifen and aromatase inhibitor on any cognitive domain was observed. |