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. 90% of kidney malignancies express folate receptor alpha (FRA), and a fluorescent probe targeting FRA is readily available. 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 the investigators in the Netherlands has completed a pilot study utilizing a folate- fluorescein isothiocyanate (FITC) conjugate in 12 patients with ovarian cancer. They have subsequently performed this study on 20 more patients without any 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. The only known allergy is those patients which have an insect reaction (fluorescein is derived from the firefly insect, folate is an essential vitamin). This drug has also been used at a higher dose for therapeutic purposes in patients with metastatic renal cell carcinoma in the United States. However, this drug will be used at a lower dose for a diagnostic purpose only.