A new study has found that exercise helps reduce joint pain caused by aromatase inhibitors.

The study is called “Randomized trial of exercise vs. usual care on aromatase inhibitor-associated arthralgias in women with breast cancer: The hormones and physical exercise (HOPE) study”. The findings were presented on Dec. 12, 2013 at the 2013 San Antonio Breast Cancer Symposium.

Aromatase inhibitors are commonly used in postmenopausal women who have been diagnosed with breast cancer. These drugs work by blocking the enzyme called aromatase, which converts androgens (male hormones) into estrogen.  Androgens produced in the adrenal glands are converted into estrogen by the enzyme aromatase, which is mostly produced in fat cells.  The more overweight a woman is, the more aromatase she has; therefore the more estrogen she manufactures in her body fat.

Aromatase inhibitors reduce the total amount of estrogen in the body.  Less estrogen in the bloodstream means that less estrogen reaches estrogen receptors in breast cancer cells, therefore the cells are not stimulated to grow.  Aromatase inhibitors are taken in tablet form, usually for five years or longer.

There are currently three different aromatase inhibitors: anastrozole (brand name Arimidex), letrozole (brand name Femara) and exemestane (brand name Aromasin).  An increasing amount of evidence is showing that aromatase inhibitors are more effective than tamoxifen in the treatment of breast cancer in post-menopausal women.  They also seem to be more effective than tamoxifen in post-menopausal women with HER2 positive tumours (which don’t respond as well to tamoxifen).  The side effects of aromatase inhibitors are mostly related to estrogen suppression.  Side effects include:

  • Hot flushes.  Aromatase inhibitors are less likely to produce hot flushes than tamoxifen and they are less intense.
  • Joint and muscle pains.
  • Increased risk of osteoporosis.  The risk of osteoporosis increases at menopause because of declining estrogen levels. Aromatase inhibitors reduce estrogen levels even further; therefore bones do become thinner and weaker as a result of treatment.  Drugs called bisphosphonates are often given to breast cancer patients taking aromatase inhibitors in order to slow bone loss.  Examples of bisphosphonates are Fosamax, Actonel and Didrocal.
  • Fatigue
  • Vaginal dryness and loss of libido
  • Possible increase in cholesterol levels

Apart from reducing joint pain, regular exercise helps to improve mood, energy levels and even improves prognosis for women currently in treatment for cancer.

For more information, read our book “Breast Cancer Prevention Guide“.