Tab. 2.

Proposed diagnostic methods for GEP-NEN^(1,2,18,19)

Suspected NEN of the stomach, duodenum

1.Gastroscopy with histopathological examination (determination of histopathological diagnosis) 2.EUS (assessment of intramural invasion depth the presence of metastasis in regional lymph nodes) – lesions of 1–2 cm or multiple lesions 3.Abdominal CT scan – after filling the stomach with water to the full (stomach assessment) or 2-stage water drinking (assessment of the duodenum) and i.v. contrast administration / contrast-enhanced MRI – disease staging, distant metastasis detection 4.SRS – disease staging, distant metastasis detection

Suspected NEN of the pancreas

1.EUS – in every case with clinical diagnosis of a secreting tumour and when indications for biopsy are present 2.Hormonally active NEN of the pancreas – SRS (detection of lesions not revealed using anatomical imaging, search for the primary lesion and determination of the actual stage of the neoplasm; first-line method for the diagnosis of early recurrence, disease monitoring and selecting the right therapy), subsequently EUS and CT/MRI (assessment of anatomical location and the possibility to remove the primary lesion, cancer staging and treatment response monitoring) 3.Hormonally inactive NEN of the pancreas: CT/MRI (as above), subsequently SRS (as above) 4.Rapidly growing NEC and NEN of the pancreas – 18FDG PET/CT

Suspected NEN of the small intestine, metastatic NEN of unknown point of origin

1.SRS – method preferred for lesions smaller than 1 cm, search for the primary lesion 2.CT, MRI – search for the primary lesion, disease staging and assessment of treatment response 3.CT or MRI enterography/enteroclysis – determination of location 4.Colonoscopy with distal ileum assessment – search for the primary lesion and exclusion of concomitant cancer (colon cancer) 5.Video capsule endoscopy (VCE) and balloon enteroscopy or spiral enteroscopy – direct assessment of the mucous membrane; poorly available procedure 6.EUS – no utility for small intestinal lesion diagnosis

Suspected NEN of the colon

1.Colonoscopy – procedure of choice in the diagnosis of colon tumours 2.EUS – in rectal NEN of ≥5 mm; ultrasound miniprobes during colonoscopy – in colon tumours diagnosed as polyps/submucosal lesions 3.Abdominal and pelvic CT/MRI with the gastrointestinal tract filled with negative contrast – disease staging and assessment of metastases 4.CT colonography – it is not possible to perform complete colonoscopy in the case of lesions which fully obstruct the intestinal lumen 5.SRS – staging of the neoplastic process, assessment for SSA and PRRT 6.PET-CT following 18F-DOPA assessment – in the case of a negative SRS result assessment for antiproliferative treatment using SSA and PRRT 7.18FDG-PET/CT – in patients with NEC, patients with a rapidly growing NET with a negative SRI result and in patients assessed for radioisotope treatment

EUS – endoscopy ultrasound; EUS-FNA – EUS fine-needle aspiration; EUS-RFA – EUS-guided radiofrequency ablation; CEUS – contrast-enhanced ultra-sonography; IDUS – intraductal ultrasonography; IOUS – intraoperative ultrasonography; SRS – somatostatin receptor scintigraphy; SSA – somatostatin analog; PRRT – peptide-receptor radionuclide therapy; ⁹⁹mTc-SPECT – ⁹⁹mTc-single-photon emission computed tomography; ⁶⁸Ga-DOTA-PET – ⁶⁸Ga--DOTA-positron emission tomography; ¹⁸FDG-PET – ¹⁸FDG-positron emission tomography; ¹³¹I-MIBG – ¹³¹I-MIBG – single-photon emission computed tomography