By Ed Susman
CHICAGO -- December 3, 2008 -- Researchers suggest that before a woman undergoes definitive treatment for breast cancer, she should undergo breast-specific gamma imaging (BSGI) to determine if other malignancies exist in the same or contralateral breast.
Breast-specific gamma imaging locates tumours by pinpointing areas of increased metabolic functioning -- a characteristic of malignancy, said Rachel F. Brem, MD, Breast Imaging and Interventional Cancer, George Washington University Medical Center, Washington, DC.
"X-rays and magnetic resonance [imaging] find breast lesions by looking at their shape; [BSGI] locates these lesions by how they function," Dr. Brem said in her presentation on December 3 here at the Radiological Society of North America (RSNA) 94th Annual Meeting.
For the procedure, technetium sestamibi is injected into the patient's arm and BSGI picks up where the tracer material accumulates in the breast. She said BSGI will be useful as an adjunct to mammography or as a screening tool for high-risk patients.
For their study, Dr. Brem and colleagues reviewed the scans of 159 women in which doctors used BSGI following initial discovery of a tumour.
Results showed that the procedure revealed a new suspicious area in 56 cases. Eventually 45 of those suspicious regions were biopsied, and 14 of those biopsies came back positive for cancer.
Overall, 9% of the women had additional occult cancers, she said. Nine of the tumours were found in the same breast as the original lesion; 5 were in the contralateral breast. The tumours detected using BSGI ranged in size from 0.1 to 3.6 cm in diameter.
"Gamma imaging can impact treatment management," Dr. Brem said. She illustrated one case of a woman who was being considered for lumpectomy, but gamma imaging found another extensive tumour a distance from the original finding, requiring a change in management to mastectomy.
The women in her study were aged 54 years on average (range 19-93 years). They all had been diagnosed to have 1 biopsy-proven breast cancer. About 73% of women in the study were classified as having dense breasts, a condition that makes diagnosis with traditional modalities more difficult.
The study was funded by George Washington University Medical Center. Dr. Brem disclosed that she is a board member of Dilon Technologies. A Dilon device was used in the study.
[Presentation title: Breast Specific Gamma Imaging in Women With One Suspicious or Cancerous Breast Lesion. Abstract SSM01-05]
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