LOCALIZING THE NEUROENDOCRINE TUMORS

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LOCALIZING THE NEUROENDOCRINE TUMORS

• After the Dx of a hormone-secreting tumor
• If metastatic disease is not present.
• Determining the response to therapy.

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Imaging of Neuroendocrine Tumors

• Ultrasound low sensitivity for primary 30
  metastases 70
• Spiral CT / MRI primary up to 70 metastases
  90
• Octreotide scan primary 80, metastases
  95 most useful except for insulinoma
• EUS 95 pancreatic primary tumor gastric
  carcinoid rectal carcinoid
• Angiography Primary pancreatic tumor invasive
  Last tool.
• Intraoperative Ultrasound, trans-illumination,
  palpation

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CT scan

•  
• Carcinoid liver metastases are often
  hypervascular, and may become isodense relative
  to the liver with the administration of
  intravenous contrast

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Somatostatin receptor scintigraphy (SRS) 

• Somatostatin receptors many pancreatic endocrine
  tumors
• Proven particularly effective for visualizing
  gastrinomas, glucagonomas, nonfunctioning
  pancreatic tumors, and carcinoid tumors
• -SRS is a more useful for the detection of
  metastatic disease
• 
  
• -An exception is insulinomas, only 50 of which
  express type 2 somatostatin receptors.
• -Accuracy can be improved further with the
  addition of single photon emission computed
  tomography (SPECT)

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Octreotide Scan
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Cont.
-The use of SPECT rather than planar imaging
increased the detection rate of SRS (from 190 to
204 individual hepatic metastases), but this
still did not surpass that of MRI (which
identified 394 lesions) -Many authorities
consider MRI to be the imaging study of choice
for the detection of metastatic NETs
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MRI

• The greater sensitivity of MRI for liver
  metastases as compared to both SRS and CT
• MRI detected significantly more metastases than
  either planar SRS or CT (sensitivity rates for
  MRI 95, planar SRS 79, CT 49)

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PET

•  PET improved detection and staging of NETs in
  the future
• Based on Increased metabolic activity due to
  malignancy
• In a study of patients with carcinoid (n 24) or
  pancreatic islet cell tumor (n 23) who had at
  least one lesion on conventional imaging,
  integrated PET/CT imaging with had a diagnostic
  sensitivity of 98 for carcinoid tumors, compared
  to for SRS 49, SRS/CT 73 and CT alone 63
• Among patients with islet cell tumors, the
  diagnostic sensitivity was 96, compared to 46,
  77, and 68 percent for SRS 46, SRS/CT 77 and CT
  alone 68

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NEUROENOCRINE TUMORS

• ROLE OF EUS

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Endoscopic ultrasonography

• High-resolution imaging of the pancreas as
  small as 2 to 3 mm.
• In patients who had negative ultrasonography and
  CT scans, EUS detected endocrine tumors in the
  pancreas with high sensitivity (82 percent) and
  specificity (95 percent) .
• EUS had an overall sensitivity and accuracy of
  93 for detecting pancreatic islet cell tumors .
• EUS has also proven to be a useful tool for
  identifying tumors in the duodenal wall and
  peripancreatic lymph nodes (sen. 58).

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Cont.

• EUS-guided FNA may help identify the type of
  tumor.
• EUS is limited by the requirement of a highly
  skilled endoscopist, and by its inability to
  consistently visualize the pancreatic tail.

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DDRC report for insulinoma

• The overall accuracy of EUS in the detection of
  pancreatic insulinoma in 48 referred cases was
  85 , while the sensitivity for insulinoma in the
  head of the pancreas was 100 .

Sotoudehmanesh et al Endoscopic ultrasonography
in the localization of insulinoma. Endocrine.
2007 31(3)238-41.
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Pancreatic Endocrine Tumors
US / CT staging EUS (
localization ) Accuracy 85-100
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Intraoperative localization techniques 

• Intraoperative ultrasonography IOU
• IOU combined with palpation of the organ, the
  sensitivity 83-100.
• Intraoperative transillumination has equivalent
  efficacy (sensitivity of 83 ) for the
  localization of duodenal wall gastrinomas.

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RECOMMENDATIONS

• Gastrinoma  SPECT gt EUS gt Angiographygt IOU
• Carcinoid--- SPECTgt EUS gt DBE
• Insulinoma----MRI/CT gt EUS gt Angiog. gt IOU
• Other pancreatic endocrine tumors 
• Usually large and detected by CT.