Page 126 - Fluorescence-guided cancer surgery

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Chapter 8
DISCUSSION
In this feasibility study we investigated the use of NIR uorescence imaging with the clinically available, non-targeted uorescent tracer ICG in ovarian cancer patients who underwent a surgical staging procedure or cytoreductive surgery. Malignant metastatic lesions were present in 2 out of 10 patients only, but we found that 100% of these histologically proven malignant lesions were uorescent using this technique. However, there was also a high false-positive rate of 62%.
In cytoreductive surgery, the goal is to remove as much tumor as possible, aiming for complete (no tumor visible after surgery) or leastwise optimal cytoreduction (residual tumor maximized to 10 mm), because the amount of residual tumor is one of the most important prognostic factors for survival in advanced stage patients. Van Dam et al.14 already showed that with the use of uorescence imaging using a folate receptor alpha targeting probe (that is over-expressed in 90-95% of ovarian cancer patients), it was possible to identify more tumor deposits than by the naked eye. In our study we could not demonstrate such an added value of NIR uorescence using the non-speci c agent ICG, because all of the uorescent, histologically malignant lesions were identi ed with the naked eye.
Treatment decisions in early stage ovarian cancer patients, for instance regarding adjuvant chemotherapy, are based on the presence of occult metastases and the extent of disease found during surgical staging procedures. If staging is not done properly, this could lead to under treatment of the patient. It has been shown that completeness of surgical staging is an independent prognostic factor for overall survival in early stage patients4. If the use of NIR uorescence imaging leads to more accurate detection of (occult) ovarian cancer metastases, more patients could be optimally staged, possibly leading to better treatment decision making and overall survival. In none of the 3 patients with early stage ovarian or fallopian tube cancer who underwent a staging procedure in this study, metastatic disease was found. Therefore, no added value of NIR uorescence imaging could be demonstrated in this study using ICG. A total of 13 uorescent lesions were observed in the 7 patients undergoing surgical staging. On pathologic testing, all 13 lesions were benign and thus false-positive. To conclude, NIR uorescence imaging could not demonstrate added value in staging procedures because no otherwise