Intraoperative Imagery of Renal Nodules With Folate-fluorescein Conjugate(EC17)

According to the National Cancer Institute, an estimated 64,770 men and women will be
diagnosed with kidney cancer in 2012. Of this number, an estimated 13,570 will die of this
disease. Surgery remains one of the best options for patients presenting with operable Stage
II or III cancers, however the five year survival rate for these candidates remains at a
dismal 63.7% for Stage II and 11% for Stage III. The high rates of recurrence suggest that
surgeons are unable to completely detect and remove primary tumor nodules in a satisfactory
manner as well as lingering metastases in sentinel lymph nodes. By ensuring a negative margin
through imaging during surgery it would be possible for the investigators to improve the
rates of recurrence free patients and thus overall survival.

Renal cell malignancies are the ideal disease to investigate intra-operative imaging. 70% of
kidney malignancies express folate receptor alpha (FRA). It is important to note that FRA is
expressed only in the proximal tubules of the kidneys, activated macrophages, and in the
choroidal plexus. Thus, the false positive detection rate is expected to be extremely low. A
group well known to us in the Netherlands has completed a pilot study utilizing a folate-FITC
conjugate in 12 patients with ovarian cancer. Another group of investigators in Mayo have
subsequently performed this study on 20 more patients without any serious adverse events
(personal communication). They report excellent sensitivity and specificity with this
technique with only grade 1 side effects (allergic reaction). All side effects reversed when
the injection was halted. Patients with a history of allergic reactions to insect bites
should not participate (fluorescein is derived from the firefly insect, folate is an
essential vitamin).