Neuroendocrine tumor recurrence: diagnosis with 68Ga-DOTATATE PET/CT.
OBJECTIVE
To evaluate diagnostic performance of gallium 68-tetraazacyclododecane tetraacetic acid-octreotate ((68)Ga-DOTATATE) in detection of recurrent neuroendocrine tumors (NETs).


METHODS
Approval was waived by the local ethics committee for this retrospective study. Between 2007 and 2011, 63 patients (mean age, 58 years) were examined with (68)Ga-DOTATATE positron emission tomography (PET)/computed tomography (CT) after primary NET curative resection. Reasons for PET/CT were regular follow-up examinations (n = 30), increased plasma levels of tumor markers (n = 27), or clinical suspicion of recurrence (n = 6). Final diagnosis was determined with histopathologic verification (n = 25) or clinical follow-up (n = 38). PET/CT scans were evaluated in consensus by two readers without blinding to clinical information and independently by two readers with blinding. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated.


RESULTS
Final diagnosis of NET recurrence was determined in 29 patients. In three other patients, tumors of nonneuroendocrine origin were diagnosed. (68)Ga-DOTATATE PET/CT helped identify NET recurrence in 26 of 29 patients (sensitivity, 90%) and exclude presence of recurrent NET in 28 of 34 patients (specificity, 82% ). PET/CT provided false-positive and false-negative results in six and three patients (PPV, 81% [26 of 32]; NPV, 90% [28 of 31]; accuracy, 86% [54 of 63]). In gastroenteropancreatic NET (n = 45), sensitivity was 94% (17 of 18); specificity was 89% (24 of 27); PPV was 85% (17 of 20); NPV was 96% (24 of 25); and accuracy was 91% (41 of 45). Two blinded readers achieved sensitivity of 79% (23 of 29) and 76% (22 of 29); specificity of 85% (29 of 34) and 94% (32 of 34) (κ = 0.80); and accuracy of 83% and 86%.


CONCLUSIONS
(68)Ga-DOTATATE PET/CT is accurate in detection of recurrent NET. Blinded PET/CT review markedly decreased sensitivity, underlining importance of considering clinical parameters in NET recurrence. Present results must be further validated to substantiate use of (68)Ga-DOTATATE PET/CT in routine follow-up after curative resection of NET.
From the Department of Nuclear Medicine (A.R.H., R.C., B.W., C.U., P.B., M.H.), Interdisciplinary Center of Neuroendocrine Tumors of the Gastro-Entero-Pancreatic System (A.R.H., C.J.A., C.S., P.B.), Department of Internal Medicine 2 (C.J.A., C.S.), Medizinische Klinik und Poliklinik 4 (M.R., F.B.), and Institute of Clinical Radiology (G.P.S.), Klinikum Grosshadern, Ludwig-Maximilians-University of Munich, Marchioninistrasse 15, Munich 81377, Germany; and Department of Nuclear Medicine, Medical University of Vienna, Vienna, Austria (M.H.).
Alexander R
AR
Haug
Ramona
R
Cindea-Drimus
Christoph J
CJ
Auernhammer
Martin
M
Reincke
Felix
F
Beuschlein
Björn
B
Wängler
Christopher
C
Uebleis
Gerwin P
GP
Schmidt
Christine
C
Spitzweg
Peter
P
Bartenstein
Marcus
M
Hacker
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology; D018358:Neuroendocrine Tumors / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D009942:Organometallic Compounds; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
D009942:Organometallic Compounds; C513399:gallium Ga 68 dotatate