Correlation between standardized uptake value of 68Ga-DOTA-NOC positron emission tomography/computed tomography and pathological classification of neuroendocrine tumors

Chalermrat Kaewput; Subapriya Suppiah; Sobhan Vinjamuri

doi:10.4103/wjnm.WJNM_16_17

World Journal of Nuclear Medicine, Table of Contents

CC BY-NC-ND 4.0 · World J Nucl Med 2018; 17(01): 34-40
DOI: 10.4103/wjnm.WJNM_16_17

Original article

Correlation between standardized uptake value of ⁶⁸Ga-DOTA-NOC positron emission tomography/computed tomography and pathological classification of neuroendocrine tumors

Authors

Chalermrat Kaewput

Department of Radiology, Division of Nuclear Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Subapriya Suppiah

¹Centre for Diagnostic Nuclear Imaging, Universiti Putra , Selangor, Malaysia
Sobhan Vinjamuri

²Department of Nuclear Medicine, Royal Liverpool University Hospital, Liverpool, UK

Abstract

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The aim of our study was to correlate tumor uptake of ⁶⁸Ga-DOTA-NOC positron emission tomography/computed tomography (PET/CT) with the pathological grade of neuroendocrine tumors (NETs). ⁶⁸Ga-DOTA-NOC PET/CT examinations in 41 patients with histopathologically proven NETs were included in the study. Maximum standardized uptake value (SUV_max) and averaged SUV SUV_mean of “main tumor lesions” were calculated for quantitative analyses after background subtraction. Uptake on main tumor lesions was compared and correlated with the tumor histological grade based on Ki-67 index and pathological differentiation. Classification was performed into three grades according to Ki-67 levels; low grade: Ki-67 <2, intermediate grade: Ki-67 3–20, and high grade: Ki-67 >20. Pathological differentiation was graded into well- and poorly differentiated groups. The values were compared and evaluated for correlation and agreement between the two parameters was performed. Our study revealed negatively fair agreement between SUV_max of tumor and Ki-67 index (r = −0.241) and negatively poor agreement between SUV_mean of tumor and Ki-67 index (r = −0.094). SUV_max of low-grade, intermediate-grade, and high-grade Ki-67 index is 26.18 ± 14.56, 30.71 ± 24.44, and 6.60 ± 4.59, respectively. Meanwhile, SUV_mean of low-grade, intermediate-grade, and high-grade Ki-67 is 8.92 ± 7.15, 9.09 ± 5.18, and 3.00 ± 1.38, respectively. As expected, there was statistically significant decreased SUV_max and SUV_mean in high-grade tumors (poorly differentiated NETs) as compared with low- and intermediate-grade tumors (well-differentiated NETs). SUV of ⁶⁸Ga-DOTA-NOC PET/CT is not correlated with histological grade of NETs. However, there was statistically significant decreased tumor uptake of ⁶⁸Ga-DOTA-NOC in poorly differentiated NETs as compared with the well-differentiated group. As a result of this pilot study, we confirm that the lower tumor uptake of ⁶⁸Ga-DOTA-NOC may be associated with aggressive behavior and may, therefore, result in poor prognosis.

Keywords

⁶⁸Ga-DOTA-NOC positron emission tomography/computed tomography - Ki-67 - neuroendocrine tumors - standardized uptake value

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