238 Background: Gallium 68 dotatate (Ga-68 DOTA) provides physiologic imaging and assists in the localization of disease in somatostatin (SSA) receptor positive neuroendocrine tumor (NET) patients. Questions regarding the value of Ga-68 DOTA imaging in the FDA post-approval era for NET patients include: usefulness in disease monitoring, correlation of Ga-68 DOTA avidity to Ki-67 index and its impact on clinical decision making. We present our experience with 200 Ga-DOTATATE scans performed at University of Kentucky. Methods: A retrospective review of the first 200 patients who had undergone Ga-68 DOTA imaging at the Markey Cancer Center from Dec 2016 to Dec 2017 was conducted. Results: 59.5% were females and the median age was 62 (30-84 years). Primary tumor sites included: small bowel 37.5%, pancreas 18.5%, bronchial 14%, colon 3.5%, rectum 2%, appendix 1.5%, adrenal 0.5%, prostate 0.5%, others 3% and unknown primary 19%. Ga-68 DOTA scan influenced clinical decisions in 39% (n = 78) patients. Ga-68 DOTA imaging identified primary tumors in 17 of 38 patients who were classified as NET of unknown primary based on CT imaging. Subgroup analysis of mean standardized uptake value (SUV) for hepatic metastatic lesions revealed 37.3 for G1 (n = 20) as compared to 32.3 for G2 (n = 37) and 17.46 for G3 (n = 4). Mean hepatic SUV of the lesion with the greatest radiolabel uptake in 96 patients was similar irrespective of exposure to SSA LAR; 31.3 versus 27.8 for SSA versus the no SSA cohorts. Conclusions: Ga-68 DOTA imaging impacted clinical decision making in 39% of NET patients (n = 200) and identified the primary site in 17 of 38 patients with unknown primary. Systemic exposure to long acting SSA does not seem to impact quality of Ga-68 DOTA scan.
Intratumor Distribution of Ki-67 Antigen Beyond Labeling Index for Clinical Decision-Making: A New Way of Counting
