Exploratory Study of 99mTc-EC20 Imaging for Identifying Patients with Folate Receptor–Positive Solid Tumors

摘要: 99mTc-EC20 is a folate receptor (FR)–targeted imaging agent consisting of the vitamin conjugated to 99mTc. FR expressed on variety epithelial cancers, with advanced cancers often expressing at significantly higher levels than earlier stages disease. The goals this pilot study were determine percentages various solid tumors that accumulate in vivo and correlate uptake immunohistochemistry (IHC) analysis expression available biopsied tumor tissue. Methods: A total 154 patients proven or suspected cancer least one lesion ≥1.5 cm underwent 99mTc-EC20. majority these (77%) had diagnosis renal cell carcinoma. remaining other tumors. Whole-body planar images obtained 1–2 h after injection, followed by SPECT region containing index lesions. was scored as no uptake, mild marked uptake. resultant data analyzed for correlation α-isoform FR, determined IHC analysis, tissue from prior subsequent surgery biopsy. Results: administration well tolerated. Tumors increased identified 68% patients, results positive 67% patients. agreement between methods 61% overall (κ = 0.096; 95% confidence interval −0.085 0.277), 72% 38% negative results. Conclusion: In approximately two thirds having FR-positive Agreement vitro poor but potentially confounded lack time sampling imaging, heterogeneous metastatic lesions same patient, inability detect β-isoform IHC. This scintigraphy indicates safe tolerated noninvasive procedure may have utility selecting likely benefit FR-targeted therapy.