Tamoxifen and/or aromatase inhibitors (AIs) (such as Aromasin) are a key part of treatment in women with hormone receptor-positive breast cancer. However, up to half of all women taking AIs, and a smaller number of women taking tamoxifen, experience joint pain and stiffness.

Tamoxifen is much less likely to cause joint pain than Aromasin. Symptoms may be experienced in the hands, arms, knees, feet, pelvic and hip bones, or back, which may coincide with starting therapy or develop after several months of therapy.

Experts aren't sure why the pain happens with AIs but attribute it to the acute drop in estrogen produced by these drugs.

While pain relievers such as acetaminophen and NSAIDs can help relieve the pain, NSAIDs themselves have their side effects and should not be taken long-term unless under a doctor's advice.

Exercise, especially weight-bearing exercise, has also been shown to be beneficial, as has abstaining from smoking, reducing alcohol intake, and relaxation.

In women with low vitamin D levels, taking vitamin D3 supplements may improve symptoms.