Post menopausal adjuvant hormone therapy for DCIS
| Aspect | Anastrozole | Tamoxifen | Notes |
| Dosing | 1 mg orally once daily | 20 mg orally once daily | Standard duration is 5 years for both drugs |
| Overall recurrence (11.6 years median follow-up) | 103 events | 118 events | 11% nonsignificant reduction favoring anastrozole |
| ER-positive recurrences (5-year treatment period) | 18 events | 33 events | 44% significant reduction with anastrozole (HR = 0.56, 95% CI = 0.31–0.99) |
| ER-positive recurrences (post-treatment period) | 40 events | 49 events | Nonsignificant difference (HR = 0.83, 95% CI = 0.55–1.27) |
| Fractures | No excess reported | Not specified | No significant difference in fracture rates |
| Cardiovascular disease | No excess reported | Not specified | No significant difference in cardiovascular events |
| Musculoskeletal events | 57% | 49% | Significantly higher with anastrozole (p < 0.0001) |
| Joint-related effects | More common | Less common | – |
| Menopausal symptoms | More common | Less common | – |
| Non-breast cancers | 147 cases | 200 cases | Significant decrease with anastrozole (OR 0.72, 95% CI 0.57–0.91) |
| Bone mineral density | May decrease | May increase | Consider bone mineral density monitoring with anastrozole |
| Total cholesterol | May increase | – | Consider cholesterol monitoring with anastrozole |
- Both drugs are taken orally once daily for a standard duration of 5 years.
- Anastrozole shows a slight, non-significant advantage in preventing overall recurrence.
- Anastrozole is more effective in reducing ER-positive recurrences during the active treatment period.
- Musculoskeletal events, joint-related effects, and menopausal symptoms are more common with anastrozole.
- Anastrozole may lead to decreased bone mineral density and increased cholesterol levels, requiring monitoring.
- Anastrozole is associated with a significant decrease in non-breast cancers.