The value of preoperative molecular breast imaging for the size assessment of invasive carcinoma and ductal carcinoma in situ

PO044
The value of preoperative molecular breast imaging
for the size assessment of invasive carcinoma and ductal
carcinoma in situ
S. Galassi1, M.L. Stazza1, M. Rondini1, A. Lazzarato1, S. Nuvoli1,
G. Madeddu1, A. Spanu1
1Unit of Nuclear Medicine, Department of Clinical, Surgical and
Experimental Sciences, University of Sassari, Sassari, Italy
Background-aim: Molecular Breast Imaging (MBI) with the technetium-
labelled cationic lipophilic radiotracers has proved to be able
to play an important complementary role to conventional imaging
procedures in the diagnosis of primary breast cancer as well as in the
preoperative local staging of disease. MBI also demonstrated a high
accuracy in the identification of residual disease following neoadjuvant
therapy. The aim of the present study was to assess the value of
preoperative MBI for the size assessment of invasive carcinoma and
ductal carcinoma in situ (DCIS) in patients with newly diagnosed
primary breast cancer.
Methods: A consecutive series of 190 patients (age: 31–78 years)
with newly diagnosed primary breast cancer scheduled to surgery was
retrospectively reviewed. Prior to surgery, all patients underwent
MBI, in both craniocaudal and mediolateral oblique projection (600 s/
view), using a high-resolution semiconductor-based device for
imaging acquisition. MBI data were correlated with surgical
histopathological findings. Pearson’s correlation coefficient was calculated
to assess differences in tumor size between MBI and
histopathological examination. Concordance was defined as a difference
B 0.5 cm between MBI and pathology.
Results: At surgery, 108 out of 190 patients had an invasive primary
tumor (invasive ductal: 95 cases, invasive lobular: 7 cases, mucinous:
3 cases, other types: 3 cases) with a median tumor size of
1.80 ± 1.83 cm at histopathological analysis and 1.90 ± 1.94 cm at
MBI (r = 0.986, p\0.00001) which over-estimated lesion size in
8/108 cases. Thirty-five/190 patients had a DCIS with median tumor
size of 1.60 ± 1.23 cm at histopathological analysis and
2.15 ± 1.50 cm at MBI (r = 0.629, p\0.00005). In this group of
patients, lesion size was overestimated at MBI in 11 cases and
underestimated in one. The remaining 47/190 patients had an invasive
tumor (invasive ductal: 41 cases, invasive lobular: 6 cases) and an
associated DCIS component. In 38 of these 47 cases, the DCIS
component was marginal; median tumor size was 1.5 ± 1.18 cm at
histology and 1.85 ± 1.16 cm at MBI (r = 0.921, p\0.00001)
which overestimated lesion size in 10 cases and underestimated in one
case. In the remaining 9/47 patients, the DCIS associated to the
invasive tumor was extensive and MBI gave an accurate size definition
of both components in 7/9 cases, overestimating in one case
and underestimating in the remaining case.
Conclusions: MBI proved a reliable diagnostic tool in the preoperative
assessment of tumor size in patients with newly diagnosed primary breast cancer. MIBI lesion size strongly correlated with
histological findings mainly in pure invasive carcinomas. Lesion size
overestimation was more frequent in DCIS. However, the size of
extensive DCIS component associated to invasive carcinomas was
correctly predicted in a high percentage of cases. These data seem to
suggest a wider application of MBI in the surgical planning of breast
cancer patients. However, they need to be confirmed in larger
prospective studies.