Imaging in situ breast carcinoma (with or without an invasive component)
with technetium-99m pentavalent dimercaptosuccinic acid and
technetium-99m 2-methoxy isobutyl isonitrile scintimammography
Introduction The aim of the study was to retrospectively define specific
features of the technetium-99m pentavalent dimercaptosuccinic acid
(Tc-99m-(V)DMSA) and technetium-99m 2-methoxy isobutyl isonitrile
(Tc-99m-Sestamibi [Tc-99m-MIBI]) distribution in ductal breast
carcinoma in situ and lobular breast carcinoma in situ (DCIS/LCIS), in
relation to mammographic, histological and immunohistochemical
parameters.
Materials and methods One hundred and two patients with suspicious
palpation or mammographic findings were submitted preoperatively to
scintimammography (a total of 72 patients with Tc-99m-(V) DMSA and a
total of 75 patients with Tc-99m- Sestamibi, 45 patients receiving both
radiotracers). Images were acquired at 10 min and 60 min, and were
evaluated for a pattern of diffuse radiotracer accumulation. The
tumor-to-background ratios were correlated (T-pair test) with
mammographic, histological and immunohistochemical characteristics.
Results Histology confirmed malignancy in 46/ 102 patients: 20/46
patients had DCIS/LCIS, with or without coexistent invasive lesions, and
26/46 patients had isolated invasive carcinomas. Diffuse Tc-99m-(V) DMSA
accumulation was noticed in 18/19 cases and Tc-99m- Sestamibi in 6/13
DCIS/LCIS cases. Epithelial hyperplasia demonstrated a similar
accumulation pattern. The sensitivity, specificity, accuracy, positive
predictive value and negative predictive value for each tracer were
calculated. Solely for Tc-99m-(V) DMSA, the tumor-to-background ratio
was significantly higher at 60 min than at 10 min and the diffuse uptake
was significantly associated with suspicious microcalcifications, with
the cell proliferation index greater than or equal to 40% and with
c-erbB-2 greater than or equal to 10%.
Conclusion Tc-99m-(V) DMSA showed high sensitivity and Tc-99m-Sestamibi
showed high specificity in detecting in situ breast carcinoma
(Tc-99m-(V) DMSA especially in cases with increased cell proliferation),
and these radiotracers could provide clinicians with preoperative
information not always obtainable by mammography
