Gamma imaging proves its prowess in DCIS detection

Breast-specific y camera scintigraphy is a highly specific tool for ductal carcinoma in situ (DCIS) detection, and provides 100 percent sensitivity when paired with mammography, according to a study published in the October issue of the Journal of Nuclear Medicine.

DCIS is a complex, problematic diagnosis. Its detection has risen dramatically with widespread deployment of screening mammography. Yet, DCIS is a heterogeneous disease; some cases remain indolent or carry minimal risk of progression to invasive breast cancer, whereas others have a higher risk of progression or recurrence. 

In addition, some cases of DCIS are mammographically occult. Breast-specific y camera scintigraphy (BSGC) appears to offer a useful complement to mammography in the diagnosis of primary breast cancer and may be useful in the detection of DCIS.

Angela Spanu, MD, of the nuclear medicine unit at University of Sassari in Sassari, Italy, and colleagues conducted a retrospective review of 33 women diagnosed with DCIS who underwent breast scintigraphy prior to surgery from January 2006 to June 2011.

Among these patients, mammography detected DCIS in 30 patients and was false-negative in three patients. BSGC detected DCIS in 31 patients and was false-negative in two. The difference in sensitivity between the two modalities was not statistically significant, and when used together, mammography and BSGC provided 100 percent sensitivity.

Spanu and colleagues referred to the role of BSGC in the detection of DCIS among women diagnosed with Paget disease, a rare malignancy often associated with invasive or in situ disease that can be difficult to detect via mammography. One of the three cases of DCIS missed by mammography and detected by BSGC fit into this category.

“The scintigraphic evidence of concomitant DCIS, as in the patient included in our series, seems to suggest that breast scintigraphy may be used as an adjunctive diagnostic tool for more accurate staging of patients with Paget disease, guiding the surgeon in planning the most appropriate surgical treatment,” wrote Spanu and colleagues.

Mammography may be limited in establishing the preoperative extent of DCIS, according to the researchers. “Thus, in the era of breast-conserving surgery, there could be the risk that mammographically undetected areas would not be surgically removed, thus increasing the rate of surgical reoperation and local recurrences.” Spanu et al called for future studies in additional patients to prospectively assess the performance of BSGC in the preoperative evaluation of patients with DCIS.

The researchers concluded with a recommendation for wider clinical application of BSGC scintigraphy as an adjunct to mammography in the diagnosis of patients with primary breast cancer.

For more about mammography adjuncts, please read "Move Over Mammo," in Health Imaging magazine.