Washington: Women with atypical hyperplasia of the breast, a precancerous condition, have a higher risk of developing breast cancer than previously thought, a Mayo Clinic study has found.

Atypia contains breast cells that are beginning to grow out of control (hyperplasia) and cluster into abnormal patterns (atypical).

Though atypia lesions are considered benign, by its risk and appearance and genetic changes, they show some of the early features of cancer.

“By providing better risk prediction for this group, we can tailor a woman’s clinical care to her individual level of risk,” said Lynn Hartmann, an oncologist at Mayo Clinic and lead author.

For their study the team followed 698 women with atypia who had been biopsied at Mayo Clinic between 1967 and 2001.

After five years, seven percent of these women had developed the disease; after 10 years, that number had gone up to 13 percent; and after 25 years, 30 percent had breast cancer.

After an average follow-up of 12.5 years, 143 women had developed the disease.

“Instead of relying on a statistical model, our study provides actual data of breast cancer cases that occurred in a population of women with atypia. These absolute risk data are preferable to a hypothetical model,” pointed out Amy Degnim, a breast surgeon at Mayo Clinic and co-lead author.

“We need to do more for this population of women who are at higher risk, such as providing the option of MRI screenings in addition to mammograms and encouraging consideration of anti-estrogen therapies that could reduce their risk of developing cancer,” Hartmann concluded.

The study appeared in the New England Journal of Medicine.