The new study shows Breast-specific gamma imaging (BSGI) appears to be comparable to magnetic resonance imaging (MRI) in its ability to detect additional occult breast cancer lesions in women who already have biopsy-proven breast cancer. The study involved 159 women. BSGI, which is also known as molecular breast imaging, found occult cancer in the same breast as the index lesion in 9 women (6%) and in the contralateral breast in 5 women (3%).

"Our study demonstrates that the detection of occult foci of breast cancer with BSGI is comparable to that reported for MRI," write the authors, led by Rachel Brem, MD, from the George Washington University Hospital in Washington, DC.

The study appears in the June issue of the Academic Radiology.

The authors say that BSGI, which requires that patients receive a radiotracer injection to image physiologic changes potentially related to breast cancer, has a number of advantages over MRI.

BSGI is more comfortable than MRI (patients are seated during imaging) and allows for "more rapid physician interpretation" because the technology generates 4 to 10 images "compared with hundreds or more for breast MRI," they write.

A radiology expert not involved with the study agreed with the authors about their comparison of BSGI and MRI.

"Patients hate MRIs," said Kathryn Evers, MD, from Fox Chase Cancer Center in Philadelphia, Pennsylvania, adding that patient comfort is greatly improved with BSGI. "It is also much easier to interpret," she said about BSGI.

Nevertheless, Dr. Evers is currently not lobbying her administrators to purchase a BSGI camera for her department of diagnostic imaging.

Currently, there is no standard of care on the use of imaging to see if additional occult breast cancer is present in the same breast as an index lesion or in the contralateral breast, said Dr. Evers.

She noted that neither the National Comprehensive Cancer Network nor the American Society of Clinical Oncology have fully codified "staging MRI" in their breast cancer guidelines.

There is ongoing debate about the use of staging MRI, and weighing benefits and risks is complex, Dr. Evers observed. "Nobody has a good answer."

Nevertheless, Dr. Evers thinks that a stronger argument can be made for imaging the contralateral breast than the breast with the index lesion because many women will receive whole-breast radiation as part of treatment.

"The contralateral breast findings are more compelling to me," she said about both MRI and BSGI, which have similar rates of finding an additional cancer in the opposite breast in women with breast cancer. "Three percent is very small number but a real number," she said about the rate of detection.

Source: Academic Radiology