More than 10 percent of women with breast cancer stopped taking a commonly prescribed drug because of joint and muscle pain, according to a new study

Researchers at the University of Michigan Comprehensive Cancer Center looked at women taking aromatase inhibitors, a drug usually given after surgery, chemotherapy and radiation treamtments.

It is meant to be taken for five years. But Dr. N. Lynn Henry said 13 percent stop taking it because of muscle and joint problems. She said more than one-quarter of women on the drug report aches and pains.

All of the 100 women in the study had been through menopause and had the type of breast cancer that is driven by estrogen, which the pills are meant to block.

Women who felt the pains generally got them within two months of starting treatment. The symptoms almost always went away after they stopped taking the drug.