Bone thinning on letrozole: monitoring and protection

Oestrogen helps keep bones strong by slowing the natural breakdown of old bone. After menopause, bone loss speeds up as oestrogen falls. Letrozole lowers oestrogen even further, so it can speed up bone thinning beyond what normally happens with age. Over several years, this can lead to osteopenia, where bone density is lower than normal, or osteoporosis, where bones become fragile and break more easily, especially in the spine, hip and wrist. Bone loss is silent, causing no pain until a fracture happens, which is why monitoring matters. Most women starting letrozole have a bone density scan, often called a DEXA scan, at the start of treatment and then repeated every one to two years, depending on the results and other risk factors. Blood tests may check vitamin D, calcium and kidney function. Everyone on letrozole is usually encouraged to protect their bones with weight-bearing and strength exercise, enough calcium from food or supplements, adequate vitamin D, not smoking, limiting alcohol and preventing falls. Women whose bones are already thin, or who have a higher fracture risk, are often offered a bone-strengthening medicine, such as zoledronic acid given as a drip, alendronic acid tablets, or denosumab injections. These medicines greatly reduce bone loss and fracture risk. Some bone density usually recovers after letrozole is stopped. With good monitoring and protection, most women can complete their full course of letrozole safely.

Letrozole speeds bone thinning

Lower oestrogen means faster bone loss than with age alone.

Bone scans track changes

A DEXA scan at the start and during treatment shows how your bones are doing.

Protection works

Exercise, calcium, vitamin D and bone medicines lower fracture risk.

Bone protection is effective, but a few realities are worth knowing.

Bone loss is silent

You will not feel bones thinning, so scans are the only reliable way to know.

Scans are not available everywhere

Some women need to travel for a DEXA scan, but it is worth arranging.

Bone medicines have their own side effects

Flu-like symptoms after a zoledronic acid drip, stomach upset with tablets and rare jaw bone problems can occur.

Recovery after stopping is partial

Some bone density returns after letrozole ends, but not always to the starting level.

What this page cannot tell you

It cannot interpret your scan. Your doctor will explain your results and fracture risk.

Fewer falls mean fewer fractures, whatever your bone density.

Make floors safer

Remove loose mats, keep wires tidy and wipe up water quickly, especially in bathrooms.

Improve lighting

Use night lights on the way to the toilet and keep stairs well lit.

Use grab rails

Rails near the toilet and bathing area, and non-slip footwear, reduce slips.

Check eyesight and medicines

Poor vision and medicines that cause drowsiness or dizziness raise fall risk.

Improve balance

Yoga, tai chi and simple balance exercises strengthen legs and steady walking.