Elsevier

Endocrine Practice

Volume 15, Issue 6, September–October 2009, Pages 521-527
Endocrine Practice

Original Article
Metabolic and Receptor Imaging in Patients with Neuroendocrine Tumors: Comparison of Fludeoxyglucose-Positron Emission Tomography and Computed Tomography with Indium in 111 Pentetreotide

https://doi.org/10.4158/EP08318.ORR1Get rights and content

ABSTRACT

Objective

To determine whether positron emission tomography/computed tomography (PET/CT) and indium In 111 pentetreotide, individually or collectively, predict the outcome of patients with neuroendocrine tumors (NETs).

Methods

Between July 31, 2002, and May 4, 2007, 29 patients with previously diagnosed NETs underwent both PET/CT and indium In 111 pentetreotide imaging at our institution. The images were evaluated for the presence of abnormalities. Clinical outcomes were classified as survival without major morbidities, survival with severe complications of disease, or death. Time to outcome was measured in months from the imaging date to outcome. Kaplan-Meier survival curves were calculated in which patient outcome was compared with results on PET/CT and indium In 111 pentetreotide imaging.

Results

Of the 29 patients, 9 had abnormalities on both PET/CT and indium In 111 pentetreotide imaging. Two patients had abnormal findings on PET/CT but normal findings on pentetreotide imaging. In 5 patients, findings were normal on PET/CT but abnormal on pentetreotide imaging. In 13 patients, normal findings were noted on both PET/CT and pentetreotide imaging. Kaplan-Meier analysis demonstrated a significant survival advantage for patients who had normal findings on PET/CT in comparison with abnormal PET/CT findings (P = .01). Patients with normal findings on indium In 111 pentetreotide imaging had a higher but insignificant survival advantage over those with abnormal results on pentetreotide imaging (P = .08).

Conclusion

For evaluation of NETs, PET/CT and indium In 111 pentetreotide are complementary. Increased metabolic activity in tumor cells is reflected by abnormalities on PET/CT. Patients who had abnormal PET/CT findings had a generally poorer prognosis and a more rapid clinical deterioration than those with normal PET/CT findings. (Endocr Pract. 2009;15:521-527)

Section snippets

INTRODUCTION

Relatively rare neoplasms that arise from neuroendocrine cells, neuroendocrine tumors (NETs) may originate from virtually any organ 1., 2., 3., 4.. Such tumors may secrete hormones that cause distinct syndromes, produce nonspecific symptoms due to mass effect, or remain asymptomatic until incidentally identified. Because NETs are a diverse group of lesions, determining the prognosis associated with a specific NET is often challenging 1., 2., 3., 4.. Clinical variables such as organ of origin,

Study Subjects

Medical records of 522 patients who underwent both PET/CT and indium In 111 pentetreotide imaging at our institution between July 31, 2002, and May 4, 2007, were retrospectively reviewed. Twenty-nine patients were selected who harbored histologically proven NETs and had undergone both indium In 111 pentetreotide and PET/ CT imaging. This retrospective study was reviewed and approved by the Cedars-Sinai Medical Center Institutional Review Board. Patients underwent PET/CT imaging either as part

Clinical Features and Course

The 29 study patients ranged in age from 24 to 78 years (median age, 50) at the time of diagnosis of the NETS (Table 1). Sixteen patients (55%) were male, and 13 (45%) were female. The anatomic sites of the tumors were as follows: pancreas 9 (31%), small bowel 4 (14%), colon 4 (14%), thyroid 4 (14%), lung 1 (3%), and other 7 (24%) (Table 2). Fifteen patients presented with metastatic disease at the time of diagnosis, determined either at surgical intervention or by imaging. One patient each had

DISCUSSION

In this study, we have shown that, among patients with NETs, those with abnormal findings on PET/CT imaging had a generally poorer prognosis and a more rapid clinical deterioration than those with normal findings on PET/CT imaging. Similarly, abnormal findings on pentetreotide imaging trended toward poor clinical outcomes, although these findings were not statistically significant. The numbers are relatively small, but patients with abnormal findings on pentetreotide imaging and normal findings

CONCLUSION

In this study, we have shown that in patients with NETs, abnormalities on PET/CT imaging trend toward an unfavorable prognosis. Pentetreotide imaging may be superior to PET/CT in identification and localization of indolent NETs because PET/CT may not show significant uptake in such tumors. A more formal analysis will be necessary to prove with greater certainty a relationship between PET/CT or pentetreotide uptake (or both) and poor clinical outcomes.

DISCLOSURE

The authors have no conflicts of interest to disclose.

ACKNOWLEDGMENT

Some of the preliminary results of this study were included in an abstract-poster presentation at the annual meeting of the Society of Nuclear Medicine; June 14 to 18, 2008; New Orleans, Louisiana.

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Published as a Rapid Electronic Article in Press at http://www.endocrinepractice.org on June 2, 2009. DOI: 10.4158/EP08318.ORR1

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