Somatostatin receptor in breast cancer and axillary nodes: study with scintigraphy, histopathology and receptor autoradiography.
We conducted a prospective analysis of somatostatin receptor scintigraphy using (111)In radiolabeled pentetreotide, a somatostatin analog, in patients with breast cancer in the aim to visualize the primary tumor and axillary or parasternal metastatic extension because some malignant breast tumors express somatostatin receptors (SS-R) in 50%, approximately. An analysis of SS-R was performed by autoradiography.


METHODS
Thirteen patients with clinically suspected breast tumors (T1, T2), and at least one palpable axillary node (N1) were included. In vivo planar scintigrams were acquired 1, 4, and 24 h after subcutaneous, then after intravenous injections (24 h delay between injections). Improved (111)In-pentetreotide uptake in invaded nodes after subcutaneous injection was hypothesized. Ex vivo scintigrams of surgical specimens were also acquired immediately after tumor resection and axillary dissection. Pathological examination and receptor autoradiography were performed on all surgical specimens.


RESULTS
Among 11 pathologically proven malignant tumors (9 ductal and 2 lobular carcinomas), only four were scintigraphically visible although six expressed SS-R receptors in vitro. Among six pathologically proven malignant nodes, four expressed SS-R, including two visualized scintigraphically. Scintigrams acquired after subcutaneous injections were less sensitive than after intravenous injections. There were no false positive. False negatives occurred in cases with small tumors with low-density or heterogeneously distributed SS-R. There was no significant difference by histological type or prognostic factors.


CONCLUSIONS
Somatostatin receptor scintigraphy does not appear to be sensitive enough to evaluate axillary node extension of breast cancer or even to confirm the presence of tumoral tissue, and this whatever the administration route for (111)In-pentetreotide.
Nuclear Medicine Department, Centre de Recherche et de Lutte Contre le Cancer, Rennes, France.
J L
JL
Albérini
B
B
Meunier
B
B
Denzler
A
A
Devillers
P
P
Tass
L
L
Dazord
T
T
Le Simple
J
J
Laissue
R
R
de Jong
J
J
Le Cloirec
J C
JC
Reubi
P
P
Bourguet
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001345:Autoradiography; D001365:Axilla; D001943:Breast Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging* / Q000378:metabolism; D018275:Carcinoma, Lobular / Q000000981:diagnostic imaging* / Q000378:metabolism; D005260:Female; D006801:Humans; D007205:Indium Radioisotopes; D008198:Lymph Nodes / Q000000981:diagnostic imaging* / Q000378:metabolism; D008207:Lymphatic Metastasis; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011877:Radionuclide Imaging; D017481:Receptors, Somatostatin / Q000032:analysis / Q000378:metabolism*; D012680:Sensitivity and Specificity; D013004:Somatostatin / Q000031:analogs & derivatives*
D007205:Indium Radioisotopes; D017481:Receptors, Somatostatin; D013004:Somatostatin; C081788:pentetreotide