title: Novel Use of Folate-Targeted Intraoperative Fluorescence, OTL38, in Robot-Assisted Laparoscopic Partial Nephrectomy: Report of the First Three Cases.
abstract: Partial nephrectomy is now the preferred surgical option for small renal tumors because it allows nephron preservation without compromising oncologic clearance. Its outcomes depend on the surgeon's ability to continuously identify the edges of the tumor during resection, thus leaving an adequate margin around the tumor without excessive removal of normal parenchyma, as well as keeping a short ischemic time. Folate receptors are highly abundant in the normal kidney, and there is a difference in folate receptor expression between malignant and normal renal tissues. Thus, the use of fluorescent agents that target folate receptors should result in differential fluorescence between the tumor and surrounding parenchyma during partial nephrectomy, which, in turn, helps tumor demarcation for identification and resection. A phase 2 study on the novel use of OTL38 in robot-assisted laparoscopic partial nephrectomy is currently in progress in our institution. The outcomes of the first three cases have shown the possible advantages of OTL38 in intraoperative tumor identification before resection and recognition of residual disease in the surrounding parenchyma after resection. The tumors typically appeared dark while the surrounding parenchyma showed brighter fluorescence. Immediately after tumor resection, the margins of all the specimens appeared to have a uniformly bright fluorescence, suggestive of an intact margin of normal renal parenchyma along the plane of excision. The pattern of intraoperative fluorescence correlates well with immunohistochemistry. No OTL38-related adverse effects have been seen among these three patients. We present the outcomes of these three cases, illustrated with intraoperative and immunohistochemistry images.
authors.affiliation: Department of Urology, Indiana University School of Medicine , Indianapolis, Indiana.
authors.forename: Cheuk Fan
authors.initials: CF
authors.lastname: Shum
authors.affiliation: Department of Urology, Indiana University School of Medicine , Indianapolis, Indiana.
authors.forename: Clinton D
authors.initials: CD
authors.lastname: Bahler
authors.affiliation: Department of Chemistry, Institute for Drug Discovery, Purdue University , West Lafayette, Indiana.
authors.forename: Philip S
authors.initials: PS
authors.lastname: Low
authors.affiliation: Center for Cancer Research, Purdue University , West Lafayette, Indiana.
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Ratliff
authors.affiliation: Department of Urology, Indiana University School of Medicine , Indianapolis, Indiana.
authors.forename: Steven V
authors.initials: SV
authors.lastname: Kheyfets
authors.affiliation: Department of Urology, Indiana University School of Medicine , Indianapolis, Indiana.
authors.forename: Jay P
authors.initials: JP
authors.lastname: Natarajan
authors.affiliation: Department of Pathology and Laboratory Medicine, Indiana University School of Medicine , Indianapolis, Indiana.
authors.forename: George E
authors.initials: GE
authors.lastname: Sandusky
authors.affiliation: Department of Urology, Indiana University School of Medicine , Indianapolis, Indiana.
authors.forename: Chandru P
authors.initials: CP
authors.lastname: Sundaram
keywords: OTL38; folate-targeted intraoperative fluorescence; partial nephrectomy