Stopping Femara (Letrozole) After 10 Years
After completing 10 years of letrozole therapy, you should stop the medication, as no evidence supports aromatase inhibitor use beyond 10 years total duration, and the risk-benefit ratio becomes unfavorable with continued treatment. 1, 2
Why Stop at 10 Years?
The maximum recommended duration for any aromatase inhibitor therapy is 10 years total. 1, 2 This recommendation is based on:
No survival benefit beyond 10 years: The MA.17R trial, which evaluated extending letrozole from 5 to 10 years, showed only a modest 4% improvement in disease-free survival (95% vs 91%) but no overall survival benefit 3
Progressive accumulation of toxicity: Bone-related adverse effects increase significantly with extended therapy, including bone pain (18% vs 14%), fractures (14% vs 9%), and new-onset osteoporosis (11% vs 6%) 3, 1
Lack of evidence beyond 10 years: No clinical trials have evaluated aromatase inhibitors beyond 10 years of total therapy, making continued use unsupported by evidence 3, 1
What Happens After Stopping
The primary benefit of extended therapy was prevention of contralateral breast cancer (0.21% vs 0.49% annually), not improved survival. 3 After stopping:
Late recurrence risk persists for years 5-20 after initial diagnosis, but this does not justify indefinite therapy 3, 1
Quality of life typically improves with cessation of menopausal symptoms and musculoskeletal complaints that persist during therapy 3
Critical Actions Before Stopping
Before discontinuing letrozole, you must address bone health: 1
Obtain a final bone density assessment (DEXA scan) to determine if bone-directed therapy (bisphosphonates or denosumab) should continue 1
Continue calcium and vitamin D supplementation indefinitely 1
Consider ongoing bone-protective therapy if osteoporosis or significant osteopenia is present 1
This Applies to All Risk Levels
Even if you have high-risk features (node-positive disease, young age at diagnosis), the 10-year maximum still applies. 1, 2 The lack of overall survival benefit in the MA.17R trial held across all risk subgroups studied, including those with lymph node involvement 3, 1
Common Pitfall to Avoid
Do not continue therapy "just to be safe" beyond 10 years. 1, 2 The accumulating bone toxicity, cardiovascular risks, and quality of life impairment outweigh any theoretical benefit, particularly given the absence of survival improvement even in the 5-10 year extension period 3, 1