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| |  Imaging Agent Shows Promise as Aid in Diagnosing Breast Cancer CHICAGO, Dec. 2, 1996 -- Results from two multi-center trials with Tc-99m Sestamibi, an investigational breast imaging agent, indicate that this radiopharmaceutical demonstrates high diagnostic accuracy for the detection of breast malignancy in patients with suspected breast cancer, according to data presented today at the Radiological Society of North America (RSNA) annual meeting. The study shows sestamibi breast imaging may be a useful adjunctive tool for diagnosing breast cancer in difficult to image patients and patients with inconclusive mammograms. "Sestamibi breast imaging shows real promise for aiding in the diagnosis of breast cancer in mammographically challenging breast tissue types," said Janet Baum, M.D., lead author for the trial data presented at the RSNA and a radiologist at Beth Israel Deaconess Medical Center in Boston, Massachusetts. "These trials indicate sestamibi breast imaging can aid in accurately detecting cancer. Tc-99m Sestamibi does not appear to be affected by breast density, and shows a high ability to detect disease in patients with lesions over one centimeter whether palpable or not." Tc-99m Sestamibi is a radiopharmaceutical used in nuclear medicine procedures. Radiopharmaceuticals are used to diagnose and treat disease. They are radioactive isotopes, often attached to biologically active molecules, and are usually injected into patients. These radiopharmaceuticals are designed to target the specific part of the body to be studied. A gamma camera is used to transform the radiopharmaceutical emissions into useful diagnostic images that illustrate both function and anatomy. Imaging procedures using radiopharmaceuticals have a proven safety profile and may be cost effective. "Although mammography is unquestionably the gold standard in breast cancer screening, dense breasts present a significant problem for mammography," said Dr. Baum. "As a follow-up to mammography, sestamibi breast imaging appears useful in evaluating dense and fatty breasts and, for a given lesion, may show higher specificity and positive predictive value than mammography." The purpose of the analysis presented at the RSNA was to evaluate the impact of breast density on the diagnostic accuracy of Tc-99m Sestamibi breast imaging for palpable and nonpalpable lesions. Six hundred seventy-three patients (286 with palpable abnormalities, 387 with nonpalpable abnormalities) were enrolled in two multicenter trials. Institutional and blinded reader image interpretations were compared with core laboratory histopathology results from excisional biopsy specimens. The results from the institutional interpretation were as follows: Palpable lesions: -- All patients -- positive predictive value 77%, negative predictive value 86%. -- In patients with fatty breasts, the sensitivity (ability to detect disease) was 87%, and the specificity (ability to exclude disease) 77%. -- In patients with dense breasts sensitivity was 86%, and specificity was 74%. Nonpalpable lesions: -- All patients -- positive predictive value 70%, negative predictive value 82%. -- For patients with nonpalpable lesions and fatty breasts sensitivity was 6l%, and specificity 86%. -- For these patients with dense breasts sensitivity was 6l%, and specificity 89%. Breast cancer is a devastating disease. The American Cancer Society estimates that 184,000 new cases of breast cancer will be detected in 1996 and 44,000 deaths will occur. There is no known way to prevent breast cancer and there is no miracle cure. In fact, metastatic disease is rarely cured and patient survival is more likely when the breast cancer is discovered early. The five-year survival rate for breast cancer when the disease is still localized is 96 percent. That rate drops to 75 percent if the cancer has spread regionally and decreases to 20 percent in patients in which the disease has metastasized at the time of diagnosis. Thus early diagnosis is the key to long-term survival and improved patient outcomes. Tc-99m Sestamibi is a product of DuPont Pharma Radiopharmaceuticals, a division of The DuPont Merck Pharmaceutical Company. Tc-99m Sestamibi is currently marketed for use in heart imaging. There have been infrequent reports of signs and symptoms consistent with seizure and severe hypersensitivity after administration of Tc-99m. DuPont Pharma Radiopharmaceuticals has filed a supplemental New Drug Application (sNDA) for this product which will be marketed under the trade name Reluma(TM) (Kit for the Preparation of Technetium Tc-99m Sestamibi) for breast imaging. A worldwide leader in the field, DuPont Pharma Radiopharmaceuticals has division headquarters in North Billerica, Massachusetts. The DuPont Merck Pharmaceutical Company, headquartered in Wilmington, Delaware, is a worldwide, research-based pharmaceutical and radiopharmaceutical company, formed in 1991 as a partnership between DuPont and Merck & Co., Inc.
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