The aim of this paper is to determine the influence of Ki-67 proliferation index on somatostatin receptor scintigraphy (SSRS) with Tc-99m-EDDA-HYNIC-TOC (Tc-99m-Tektrotyd) somatostatin analogue in patients with carcinoid tumors. Sixty-one patients (31 female, 30 male; age range: 33-76 years) were examined: 13 patients highly suspected of having a carcinoid, and 48 patients who had undergone the surgical removal of the tumor. Whole body SSRS at 4 h postinjection, spot scintigrams and SPECT of the selected regions were obtained for all patients. Tc-99m-Tektrotyd scintigraphy was classified as true positive in 26 out of 30 and true negative in 24 out of 28 patients. The sensitivity of Tc-99mTc-Tektrotyd scintigraphy was found to be as high as 94.74% in the group of patients with low mitotic index Ki67 (<2%), and it progressively decreased in patients with higher mitotic index (77.78% for Ki67 2-15% and 20% for Ki67% >20%). The likelihood of Tc-99m-Tektrotyd scan being positive when a carcinoid is present was found to be inversely proportional to the value of Ki67 proliferation index. The results showed that Tc-99m-Tektrotyd SSRS is a sensitive method for diagnosing and staging patients with well-differentiated carcinoid tumors. However, in poorly differentiated tumors with high Ki67 proliferation index, additional analyses are necessary for precise staging.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.