Intraoperative Folate-fluorescein Conjugate (EC17) Lung Cancer (CA)

According to the World Health Organization, lung cancer is the most common cause of
cancer-related death in men and women, and is responsible for 1.3 million deaths worldwide
annually as of 2004. Surgery remains the best option for patients presenting with operable
Stage I or II cancers, however the five year survival rate for these candidates remains at a
dismal 53% for Stage I and 32% for Stage II. 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 us to improve the rates of
recurrence free patients and thus overall survival.

Thoracic malignancies are the ideal disease to investigate intra-operative imaging. Over 85%
of lung and pleural 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-fluorescein isothiocyanate (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).