Breast scintigraphy with breast-specific γ-camera in the detection of ductal carcinoma in situ: a correlation with mammography and histologic subtype.
Ductal carcinoma in situ (DCIS) is a subtype of breast cancer encountered increasingly in clinical practice because of the widespread use of screening mammography. In the present study, we evaluated the usefulness of breast-specific γ-camera (BSGC) scintigraphy in DCIS identification, describing the scintigraphic findings and their correlation with mammography and histologic subtype.


METHODS
Thirty-three women, aged 41-81 y, with surgically proven DCIS were retrospectively reviewed. Before surgery, all patients underwent breast scintigraphy using a high-resolution semiconductor-based BSGC, starting 10 min after intravenous injection of 740 MBq of (99m)Tc-tetrofosmin. All patients had previously undergone mammography. A definitive histologic diagnosis was obtained in all cases after scintigraphy, and the scintigraphic findings were correlated with mammography and histologic subtype.


RESULTS
Mammography was positive in 30 of 33 patients (sensitivity, 90.9%), showing calcifications in 22 of 30 (73.3%), masses in 3 of 30 (10%), and masses plus calcifications in the remaining 5 of 30 (16.7%). Scintigraphy was positive in 31 of 33 patients (sensitivity, 93.9%), showing patchy irregular uptake in patients with calcifications and focal uptake in masses; sensitivity was higher in low- to intermediate-grade DCIS than in intermediate/high- and high-grade DCIS (100% vs. 91.3%), but the difference was not statistically significant. Two comedo-type DCIS (one 20-mm intermediate/high-grade and one 15-mm high-grade) with heterogeneously or highly dense breasts at mammography and one papillary low/intermediate-grade DCIS associated with Paget disease were true positive only at scintigraphy. Moreover, scintigraphy better assessed disease extent than did mammography in 5 additional patients. Two comedo-type DCIS (one 6-mm intermediate/high-grade and one 15-mm high-grade) were true positive only at mammography. The difference in sensitivity between scintigraphy and mammography was not statistically significant. The combined use of mammography and scintigraphy achieved 100% sensitivity.


CONCLUSIONS
BSGC scintigraphy proved to be a highly sensitive diagnostic tool in the detection of DCIS, irrespective of histologic subtype, and with a scintigraphic pattern of uptake that correlated well with mammography findings. In our series, BSGC scintigraphy demonstrated a slightly higher sensitivity than mammography and a better assessment of local disease extent. Thus, BSGC scintigraphy should represent a useful adjunctive tool in breast cancer diagnosis.
Unit of Nuclear Medicine, University of Sassari, Sassari, Italy. angela.spanu@email.it
Angela
A
Spanu
Daniela
D
Sanna
Francesca
F
Chessa
Pierina
P
Cottu
Alessandra
A
Manca
Giuseppe
G
Madeddu
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000000981:diagnostic imaging*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D015902:Gamma Cameras; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D009928:Organ Specificity; D011877:Radionuclide Imaging / Q000295:instrumentation*; D012189:Retrospective Studies