Every woman fears the worst when she gets atypical results on her yearly mammogram. But certain abnormalities may not need surgery.

Women diagnosed with lobular carcinoma in situ (LCIS) or atypical lobular hyperplasia (ALH), tissue abnormalities associated with an increased risk of breast cancer, can be monitored effectively with continued exams and mammography, a new study has found.

The findings could help many women avoid surgery, which involves general anesthesia and possible disfigurement, according to Kristen Atkins, an author on the study and a professor of pathology at the University of Virginia. Women with ALH and LCIS do have a four- to 10-times greater risk of developing breast cancer than those who do not. Because of this increased risk of cancer, most doctors believe that it is best to excise the abnormal tissue.

These findings show that some women can avoid surgery, and that yearly mammograms along with MRI or ultrasound as second-line screening tools may suffice.

Researchers studied 10 years of pathology and radiology data on 50 ALH and LCIS tissue abnormalities from 49 women aged 40 to 73 years. They were interested in seeing how many of the ALH and LCIS cases were upgraded to cancer after surgery or follow-up and the concordance or degree of agreement between mammograms and post-surgical pathology findings — the lab reports on tissue removed surgically and examined microscopically.

The surgical and mammography results agreed in 43 of the 50 cases. None of the benign concordant cases were subsequently upgraded to cancer. This strongly suggests that continued observation would have been a viable alternative to surgery. Of the seven cases where post-surgery pathology results and mammograms did not agree, two were upgraded to an early-stage, noninvasive form of breast cancer, ductal carcinoma in situ, or DCIS.

Researcher Michael Cohen, formerly at UVA and now a professor of radiology at the Emory University School of Medicine in Atlanta, repeated the study at Emory and got similar results.

“These findings show that some women can avoid surgery, and that yearly mammograms along with MRI or ultrasound as second-line screening tools may suffice,” said Cohen in a statement.

The researchers suggested that their findings will help physicians and patients make informed decisions about ALH and LCIS and potentially spare many women unnecessary surgery.

The study is published online, ahead of publication, in the journal Radiology.