Value of somatostatin receptor scintigraphy in patients with appendiceal neuroendocrine neoplasms based on clinical follow-ups

Abstract

Introduction: Appendiceal neuroendocrine neoplasms (ANEN) constitute a significant proportion of the tumours identified within the appendix. Aim: This retrospective study assesses the value of somatostatin receptor scintigraphy (SRS) in evaluating tumour extent, as well as in follow-up imaging, for those patients with confirmed well (G1) or moderately (G2) differentiated ANEN before or after surgery, and using intention to treat (ITT) analysis. Material and methods: Whole body (WB) and SPECT/CT SRS using 99mTc HYNICTOC was performed on 77 patients with confirmed ANEN to assess tumour extent before or after surgery also as follow-up imaging. Results and discussion: Of 77 patients, 71 (92%) were found to have NENG1 and 6 (8%) were found to have NENG2 ANEN. Post-surgical imaging restaging was performed on 30 patients. SRS detected active disease in 3 subjects (true positive, TP), and true negative (TN) results were found in 27 cases. Follow-up SRS imaging was performed after surgery with ITT on 47 patients, detecting TP result in single patient and TN in 46 patients, with no false positive or negative results. Sensitivity was shown to be 100%. Conclusions: SRS is a precise screening method for identifying the presence of active disease after non radical or extended surgery. However, as the primary treatment of the disease is highly effective, SRS is not a cost-effective choice for post-surgical follow-up screening.