Presentation Authors: Alexa Meyer*, Hiten Patel, Misop Han, Mohamad Allaf, Michael Gorin, M. Som Javadi, Phillip Pierorazio, Christian Pavlovich, Steven Rowe, Baltimore, MD
Introduction: Previously, we reported that SPECT/CT imaging using the mitochondrial imaging agent 99mTc-sestamibi can aid in the differentiation of benign renal oncocytomas and hybrid oncocytic/chromophobe tumors (HOCTs) from other renal tumor histologies. This observation has since been independently validated by investigators outside of our institution. As a result, we have adopted 99mTc-sestamibi SPECT/CT in the routine clinical evaluation of patients presenting with an indeterminate renal mass. The objective of this study was to determine the diagnostic performance of this imaging test using available data from published prospective studies as well as results from our clinical practice.
Methods: Meta-analyses of sensitivity and specificity for 99mTc-sestamibi SPECT/CT were performed using data from 3 published clinical trials and unpublished clinical data from our institution. Analyses were performed using random effects modeling and Freeman-Tukey double arcsine transformation to stabilize variances. Heterogeneity was assessed by computing the I2 statistic. Analyses were performed using MedCalc Version 17.9.7 (MedCalc Software bvba, Ostend, Belgium). Only cases with pathologic confirmation of tumor histology were included in the analyses. True positive was defined as any tumor diagnosed as an oncocytoma or HOCT following surgical resection or as an oncocytic renal neoplasms consistent with an oncocytoma on biopsy.
Results: Data from 167 patients with solid renal tumors imaged with 99mTc-sestamibi SPECT/CT were included in the analysis. Of these, 80 (47.9%) were imaged as part of clinical care at our institution. In total, 60 (35.9%) true positive tumors were imaged. Among the 107 imaged true negative tumors, 64 (59.9%) were clear cell RCC, 14 (13.1%) were papillary RCC, 11 (10.3%) were chromophobe RCC, and 4 (3.7%) were angiomyolipomas. The calculated values of sensitivity and specificity were 86.6% (95% CI 77.3-93.8%, I2 = 0%) and 89.1% (95% CI 82.6-94.2%, I2 = 0%), respectively.
Conclusions: Combined data from 3 prospective studies and own clinical experience demonstrate that 99mTc-sestamibi SPECT/CT accurately differentiates benign renal oncocytomas and HOCTs from other tumor histologies.