One year after breast cancer surgery, many women continue to experience pain, according to a recent study.

Researchers revealed that the factors associated with the women’s pain included chronic pain and depression before surgery, chemotherapy, and radiation therapy.

“Data on factors associated with persistent pain are needed to develop prevention and treatment strategies and to improve the quality of life for breast cancer patients,” the study authors said.

The research, published in the Journal of the American Medical Association, involved 860 women younger than 75 years of age who had undergone surgery for breast cancer that had not spread to other parts of their body.

The women were treated at the Helsinki University Central Hospital. Of these women, most experienced some degree of pain up to one year after their operation, the authors noted.