Fluorescence guidance during robot assisted sentinel lymph node biopsy

Improving the clinical utility of sentinel lymph node biopsy during RALP

Through a public private partnership between the LUMC, NKI-AvL and Intuitive Surgical Inc. we developed a robot-compatible fluorescence guided surgery approach that is designed to improve the clinical management of lymph node metastases in prostate cancer patients.

Prostate cancer presents 10% of cancers occurring in men (5-year overall survival of 88% and a 10-year survival 79%). Lymph node (LN) metastases are often the initial step in the cascade of metastatic prostate cancer. Unfortunately diagnostic imaging modalities such as magnetic resonance imaging (MRI) and positron emission tomography (PET) can be used to identify the primary tumor, but lack the sensitivity to identifying LNs that contain small metastases. For this reason the treatment in men with suspected metastatic spread is based on  extensive lymphatic dissection, a procedure that can yield surgery-induced side-effects such as lymph edema. Despite its invasiveness, 25% of the tumor positive lymph nodes are not identified with this procedure.  Therefore, surgical guidance to these lymph nodes can help to improve the oncological outcome, while minimizing the invasive nature of the procedure.

Via the use of our in house developed “hybrid tracer” (indocyanine green-99mTc-nanocolloid) we are able to preoperatively map the lymphatic drainage of the prostate and visualize the exact same features during surgery, using fluorescence imaging. We hypothesized that improvements in tracer deposition could help enhance the tumor specificity of this approach, and with that further increase the accuracy of the procedure.

Through our studies, we have demonstrated that there is a direct relation between the drainage pattern of the hybrid tracer and the likelyhood of detecting metastases containing lymph nodes. Initial indications for this relation were provided in 73 patients. To validate these findings we have initiated a randomised clinical trail, that has nearly been completed (Nov 2016: 106/120 patients included). Initial analysis of the data coming from this trial suggests that the metastatic find rate improved following intratumoral tracer deposition. Such a positive outcome indicates that the proposed approach would be suitable for dissimination into other clinical sites.

For more information, see here.

 

Summary
Robot-assisted surgery is becoming an accepted treatment modality in prostate cancer and its accuracy can be refined using fluorescence guidance. In this project we translated a robot-compatible hybrid surgical guidance technology that can be used to guide the urologist to the lymph nodes that are most likely to contain tumor metastases.
Technology Readiness Level (TRL)
8 - 9
Time period
36 months
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