Additional information gained by positron emission tomography with 68Ga-DOTATOC for suspected unknown primary or recurrent neuroendocrine tumors

Yuji Nakamoto, Kohei Sano, Takayoshi Ishimori, Masashi Ueda, Takashi Temma, Hideo Saji, Kaori Togashi

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Objective: Positron emission tomography (PET)/computed tomography (CT) using 68Ga-labeled 1,4,7,10-tetraazacyclododecane-N,N′,N″,N‴-tetraacetic acid-d-Phe1-Tyr3-octreotide (DOTATOC) has been used to detect neuroendocrine tumors (NETs). The purpose of this study was to investigate the clinical efficacy of DOTATOC-PET/CT for detecting clinically suspected NETs when conventional imaging modalities were negative or inconclusive, in terms of additional value. Methods: A total of 46 patients were analyzed retrospectively. Among them, 14 patients underwent a DOTATOC-PET/CT scan for detecting unknown primary tumors after histopathological confirmation of a NET at metastatic sites (group A): 7 patients for detecting metastasis or recurrence after surgery for NET because of their high hormone levels but with no recurrence detected by other imaging modalities (group B); the remaining 25 patients for detecting suspected NETs because their hormone levels were high with no history of histopathologically proven NET (group C). Additional information was assessed, according to each situation. Results: In group A, unknown primary tumors were suspected by DOTATOC-PET/CT in 8 of 14 patients (gastrointestinal/pancreatic NET in 7 patients, prostatic cancer in 1 patient), but prostatic cancer was not confirmed by histopathology (i.e., false positive). In group B, DOTATOC-PET/CT depicted lesions in six of seven patients, including nodal metastasis (n = 5) and liver metastasis (n = 1). In group C, DOTATOC-PET/CT did not demonstrate any abnormal foci except in one case of pancreatic NET. Additional information was obtained in 50, 86, and 4 % of cases, in groups A, B, and C, respectively. Conclusions: DOTATOC-PET/CT was useful for detecting NETs, especially when recurrence or metastases were suspected because of high hormone levels after surgery for a NET. It is unlikely, however, that additional information can be acquired in patients with no history of NET simply based on high hormone levels.

Original languageEnglish
Pages (from-to)512-518
Number of pages7
JournalAnnals of nuclear medicine
Volume29
Issue number6
DOIs
Publication statusPublished - Jul 25 2015

Keywords

  • DOTATOC
  • Neuroendocrine tumor
  • PET/CT
  • Somatostatin

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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