Characteristics of neuroendocrine neoplasm metastasis in somatostatin receptor PET/CT imaging: a retrospective analysis

Abstract

Objective To investigate the characteristics of NEN metastasis with SSTR PET/CT and to correlate the results with FDG-PET and pathology. Methods From November 2011 to August 2016, a total of 43 patients with NEN (18 males, 25 females; age range: 26-74 years) were recruited into this retrospective study; they underwent 68Ga-DOTA-TATE PET/CT (TATE-PET) imaging 40-60 min after 44.4-229.4 MBq 68Ga-DOTA-TATE administration. Metastases in 31 patients were confirmed by histopathology and in 12 patients by follow-up and other imaging modalities. Twenty-eight of 43 patients finished routine FDG-PET in a week after TATE-PET. PET/CT results were considered positive when the metastatic lesions were tracer-avid. ROI was drawn over each lesion for size and SUV measurement. χ2 test and Pearson correlation analysis were used for statistical analysis. Results (1) Of 43 patients, TATE-PET detection rates of metastasis in the liver, lymph nodes, bones and lungs were 85.7%(30/35), 12/13, 7/7, 2/3, respectively, with their corresponding SUVmax of 18.1(11.3-23.3), 10.8(5.4-15.6), 7.7(4.2-9.9) and 1.8(1.3-2.3), respectively. Statistical correlation between size and SUVmax was found in metastatic bone lesions(r=0.233, P 0.05. Compared with FDG-PET, TATE-PET was superior in demonstrating metastasis in the liver and bones (70.0%(14/20) vs 65.0%(13/20), 3/3 vs 2/3), equal in detecting lung metastasis (both 2/3) but inferior in demonstrating metastasis in lymph nodes(9/10 vs 10/10). Conclusions The capability of TATE-PET in revealing NEN metastasis varies depending on lesion localization and histologic grade. TATE-PET and FDG-PET are complementary to each other in detection of NEN metastasis, but without obvious relationship to histologic grade. Key words: Neuroendocrine tumors; Carcinoma, neuroendocrine; Neoplasm metastasis; Positron-emission tomography; Tomography, X-ray computed; Gallium radioisotopes; Octreotide; Deoxyglucose