Indium-111-pentetreotide scintigraphy and somatostatin receptor subtype 2 expression: new prognostic factors for malignant well-differentiated endocrine tumors.
OBJECTIVE
Well-differentiated metastatic endocrine carcinomas are difficult to manage because of variable disease outcome. New prognostic factors are required. These tumors overexpress somatostatin receptors (sst), implying the use of somatostatin analogs for tumor localization by somatostatin receptor scintigraphy using indium-111-pentetreotide ((111)In-pentetreotide) and for medical treatment. The aim of the present study was to evaluate the correlation between (111)In-pentetreotide scintigraphy, sst receptor expression, and prognosis.


METHODS
Between 1994 and 2002, 48 consecutive patients with well-differentiated endocrine carcinomas and a negative (111)In-pentetreotide scintigraphy were retrospectively paired according to sex, age, and tumor localization with 50 patients with well-differentiated endocrine carcinomas and a positive tracer uptake at (111)In-pentetreotide scintigraphy. Overall survival and expression of sst1 to sst5 receptors by immunohistochemistry were assessed.


RESULTS
The lack of tracer uptake at the (111)In-pentetreotide scintigraphy seemed to be a poor prognostic factor (P = .007) for overall survival by Kaplan-Meier test and in multivariate analysis; age and absence of clinical secretory syndrome also seemed to be poor prognostic factors. The tracer uptake (positive (111)In-pentetreotide scintigraphy) correlated with the tumor expression of somatostatin receptor sst2 (P < .001) but not with that of sst1, sst3, sst4, or sst5. In a bivariate analysis, lack of sst2 expression also significantly correlated with poor prognosis.


CONCLUSIONS
We demonstrate the prognostic value of (111)In-pentetreotide scintigraphy in well-differentiated malignant endocrine tumors. In these tumors, sst2 somatostatin receptor expression correlates with both tracer uptake and a better prognosis.
Asnacios
Amani
A
Department of Medical Oncology, Claudius Regaud Institute, Toulouse-Purpan, France.
Courbon
Frédéric
F
Rochaix
Philippe
P
Bauvin
Eric
E
Cances-Lauwers
Valérie
V
Susini
Christiane
C
Schulz
Stefan
S
Boneu
Andrée
A
Guimbaud
Rosine
R
Buscail
Louis
L
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D004701:Endocrine Gland Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000473:pathology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D007205:Indium Radioisotopes; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D011379:Prognosis; D011877:Radionuclide Imaging; D017481:Receptors, Somatostatin / Q000378:metabolism*; D012189:Retrospective Studies; D013004:Somatostatin / Q000031:analogs & derivatives*
D014408:Biomarkers, Tumor; D007205:Indium Radioisotopes; D017481:Receptors, Somatostatin; D013004:Somatostatin; C093733:somatostatin receptor 2; C081788:pentetreotide