Does Tamoxifen Become Less Effective Over Time?

— -- Question:Does tamoxifen become less effective over time?

Answer: Five years of tamoxifen therapy appears to give the maximum benefit, and continuing beyond five years doesn't add to the benefit in most women. It can add to toxicity and it certainly adds to costs. The benefits of tamoxifen however don't stop with the last tablet; we can show that those original five years of tamoxifen continue to reduce the risk of recurrence for at least an additional ten years. However breast cancer is a chronic disease; it's not at all rare for there to be recurrences -- five, ten, fifteen years or more after original diagnosis. We've now been able to show that switching to an aromatase inhibitor after five years of tamoxifen, even, is more effective in preventing a recurrence. Women who are post-menopausal and completing their five years of tamoxifen should indeed discuss that option with their doctors.

Next: Are there different types of hormonal therapy for breast cancer and what are my options if my cancer does not respond to the type prescribed?

Previous: What is tamoxifen and what are its benefits?