Breast-Specific Gamma Imaging more effective than ultrasound in finding cancers

Results of a study on Breast-Specific Gamma Imaging (BSGI) presented at the annual breast meeting of the American Society of Clinical Oncology in Washington, D.C., showed that BSGI was nearly twice as effective in finding cancers and more than three times as likely to lead to the correct diagnosis when compared to ultrasound.

Breast-specific gamma imaging (BSGI) is a molecular breast imaging technique being used more frequently as a diagnostic tool in breast centers across the nation. BSGI complements the anatomical imaging of mammography and is performed using an injection of the radiopharmaceutical Sestamibi, an imaging agent that when paired with breast-optimized gamma cameras helps determine the function of breast tissue.

A dedicated breast surgeon in Philadelphia, Dr. Ann Rosenberg, was the lead author on the retrospective, multicenter study. Rosenberg and her group compared the results of BSGI and ultrasound in patients who had dense breast tissue and a remaining diagnostic concern after mammography. The study was performed using a Dilon 6800 Gamma Camera with the standard recommend dose of approximately 20 millicuries of Sestamibi. The results show that BSGI was nearly twice as effective in finding cancers and more than three times as likely to lead to the correct diagnosis when compared to ultrasound.

Another recent study, by Edward Hendrick, PhD., reported in the August 2010 issue of Radiology that the radiation dose from BSGI was higher than mammography and recommended that it should not be used in annual screening without evidence of disease or significant risk of developing breast cancer. "We couldn't agree more and that is not the role for this technology," said Dr. Anne Rosenberg. "We often see patients with mammograms that are very difficult to interpret, but provide some indication that there might be cancer lurking in the dense tissue. Historically, ultrasound would be used to examine these patients and often the results would be equally confusing because both mammography and ultrasound examine the anatomy or structure of breast tissue. For patients with dense breasts, there is a lot of structure to look through which can potentially obscure the features common to breast cancers."

Rosenberg concluded that for patients with dense breasts and an unresolved clinical concern, the benefit of performing BSGI outweighed the radiation risk by a factor of 295:1. "The risk of a missed cancer is huge compared to the small radiation dose the patient receives in a BSGI study. As physicians, we are always weighing the risk of all medical procedures against their benefit to the patient. There is no question that for these patients the benefit of BSGI is well worth the risk."