How long will you be on letrozole?

For early hormone-receptor-positive breast cancer, letrozole is most often taken for five years. Some women take it for the whole five years straight after surgery, while others start with tamoxifen for two to three years and then switch to letrozole to complete about five years in total. For women whose cancer had a higher chance of returning, such as those with cancer in several lymph nodes or a large tumour, doctors may suggest continuing hormone therapy for longer, so that the total time on hormone tablets reaches seven to ten years. This is called extended hormone therapy. Research shows that extending treatment lowers the chance of the cancer returning a little further, mainly by preventing late recurrences and new cancers in the other breast, but the extra benefit is smaller for women whose risk was low to begin with, and the side effects, especially bone thinning, continue. So the decision about how long to go on is personal and is usually made around the five-year mark, weighing your original cancer details, how you have coped with side effects and the health of your bones. When breast cancer has spread, letrozole is used differently. It is taken for as long as it keeps the cancer under control and the side effects are manageable, which may be months or many years. Never stop early on your own, as missing years of treatment can reduce its protective effect.

Five years is the usual starting point

Most plans for early breast cancer are built around five years of hormone therapy.

Longer for some women

Extended treatment up to about ten years in total is considered when the risk of return is higher.

Advanced cancer is different

With spread, letrozole continues as long as it keeps working and you tolerate it.

There is no single right answer to how long letrozole should be taken, and experts still debate the best length for women at moderate risk.

The extra benefit of going longer is modest

Trials of extended treatment show a smaller gain than the first five years give. For some women the gain is worthwhile; for others the side effects outweigh it.

Tests do not settle it for everyone

Some genomic tests try to predict late recurrence risk, but they are not routinely used for this decision and are not always available.

Stopping early is common but costly

Many women stop because of joint pain or other side effects. Talking to your team first often finds a way to continue, such as switching to anastrozole or exemestane.

What this page cannot tell you

It cannot set your treatment length. Your oncologist can, with your full history.

Finishing hormone therapy can bring relief and also some worry, because the tablet may have felt like protection.

Side effects often ease

Joint stiffness and hot flushes usually improve over the following weeks to months, and bone density may partly recover.

Follow-up continues

You will still have regular reviews and breast imaging, often for many years.

Keep healthy habits

Staying active, keeping a healthy weight and limiting alcohol support your long-term health.