A1 Refereed original research article in a scientific journal
Prediction of the aggressiveness of non-functional pancreatic neuroendocrine tumors based on the dual-tracer PET/CT
Authors: Majala Susanna, Seppänen Hanna, Kemppainen Jukka, Sundström Jari, Schalin-Jäntti Camilla, Gullichsen Risto, Schildt Jukka, Mustonen Harri, Vesterinen Tiina, Arola Johanna, Kauhanen Saila
Publisher: EJNMMI Research
Publishing place: © Springer Nature Switzerland AG
Publication year: 2019
Journal: EJNMMI Research
Article number: 116
Volume: 9
Issue: 1
First page : 1
Last page: 12
Number of pages: 12
ISSN: 2191-219X
eISSN: 2191-219X
DOI: https://doi.org/10.1186/s13550-019-0585-7
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/44000674
Background: Predicting aggressive behavior of nonfunctional
pancreatic neuroendocrine tumors (NF-PNET) remains controversial. We wanted to
explore, in a prospective setting, whether the diagnostic accuracy can be
improved by dual-tracer functional imaging 68Ga-DOTANOC and 18F-FDG-PET/CT
in patients with NF-PNETs.
Methods: Thirty-one patients with NF-PNET (90% asymptomatic)
underwent PET-imaging with 18F-FDG and 68Ga-DOTANOC,
followed by surgery (n=20), an endoscopic ultrasonography and fine-needle biopsy (n=2) or follow-up (n=9). A focal activity on PET/CT greater
than the background that could not be
identified as physiological activity was considered to indicate tumor tissue. The imaging results were compared to the
histopathology. The mean follow-up time was 31.3 months.
Results: Thirty-one patients presented a total of 53
lesions (40 histologically confirmed) on PET/CT. Thirty patients had a 68Ga-DOTANOC-positive
tumor (sensitivity 97%) and ten patients had an 18F-FDG-positive
tumor. In addition, one 68Ga-DOTANOC-negative patient was 18F-FDG-positive.
18F-FDG-PET/CT was positive in 19%
(3/16) of the G1 tumors, 63% (5/8) of the G2 tumors and 1/1 of the well-differentiated
G3 tumor. 68Ga-DOTANOC-PET/CT was positive in 94% of the G1 tumors,
100% of the G2 tumors and 1/1 of the well-differentiated G3 tumor. Two out of six (33%) of the patients with lymph node
metastases (LN+) were 18F-FDG-positive. The 18F-FDG-PET/CT correlated with
tumor Ki-67 (P=0.021). Further, the
Krenning score correlated with tumor Ki-67 (P=0.013).
18F-FDG-positive tumors were significantly larger than the 18F-FDG-negative
tumors (P=0.012). 18F-FDG-PET/CT
showed a positive predictive value of 78% in the detection of potentially
aggressive tumors (G2, G3 or LN + PNETs); the negative predictive value was
69%.
Conclusions: 18F-FDG-PET/CT is useful to predict
tumor grade but not the LN+ of NF-PNETs. Patients with 18F-FDG-avid NF-PNETs
should be referred for surgery. The 68Ga-DOTANOC-PET/CT also has prognostic value
since the Krenning score predicts the histopathological tumor grade.
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