Single institution experience, including 1200 studies, of clinical value somatostatin receptor scintigraphy-99mTc HYNICTOC (Tektrotyd), to evaluate patients with well differentiated gastroenteropancreatic neuroendocrine neoplasm/tumors

Objectives clinical value of somatostatin receptor scintigraphy (SRS) using 99mTc-HYNICTOC (Tektreotyd), whole body (WB) SPECT, in patients with well differentiated gastro-entero-pancreatic neuroendocrine neoplasm (GEP-NEN).

Methods Retrospective study 658 patients (pts) confirmed well differentiated GEP-NEN, (WHO 2010, NETG1/G2). Overall 1200 examination performed to detect: primary tumors, assess stage of disease and evaluate imaging follow-up after completed resection. In each case SRS WB-SPECT, using 99mTc-HYNIC-Tyr3-Oktreotide-Tektrodyd (Radioisotope Center-Polatom, NCBJ; Otwock, PL). The sensitivity and specificity PPV and NPV were calculated per pts and per study.

Results NETG1-380 and G2-278 pts, local spread of disease (Clinical Stage) CS I-IIIA 275 (42%), regional with lymph nodes involvement CS IIIB 112 (17%) and mts in 266 (41%). The detection of primary tumor due to clinical suspicious in 32 pts with sensitivity and specificity 91% and 100%. Stage of disease was evaluated in 468 pts in 728 studies as initial, during or after therapy. Sensitivity, specificity PPV and NPV per patients were as follows (95%, 92%, 97% and 86%) and per examination (97%, 92%, 98%, 89%). In group of patients with imaging follow-up, sensitivity, specificity, PPV, and NPV per pts were: 90%, 95%, 82% and 98% or per examination: 91%, 97% 91% and 98%.

Conclusions WB-SPECT SRS using 99m Tc HYNICTOC is very useful in patients with well differentiated NETG1 or G2. High diagnostic accuracy was documented in large number of pts with various stage of disease and also in imaging follow-up. Additional it is cheap and easy to perform in all Nuclear Medicine departments due to labelled with 99mTc.