Het gebruik van indocyanine groen voor de detectie van de schildwachtklier bij mannen met prostaatkanker met een hoog risico op klier metastasen.
Wetenschappelijk onderzoek naar het verbeteren van de schildwachtklierprocedure voor prostaatkanker met behulp van fluorescentie

Presence of metastasis in the primary tumor draining lymph node(s) (so-called sentinel node(s)) in the pelvic region is considered a strong predicator of treatment failure in patients with prostate cancer. Postoperative histopathological examination of tissue samples obtained during surgery is considered the gold standard to assess the metastatic spread. To obtain these samples, extensive dissection of the lymphatic tissue is required, a procedure that can lead to postoperative complications such as lymphocele, injuries to the obturator nerve and/or the ureter, and lymphedema of the lower extremity. Moreover, despite an increase in resected lymph nodes, early sentinel lode studies have indicated locations of primary landing sites outside the extended field in 5-10% of cases.
Surigical pelvic lymphadenectomy can be improved with better surgical guidance along the (tumor draining) lymphatic ducts towards the (sentinel) lymph nodes. Ideally, an intraoperative imaging approach enables the surgeon to visualize and excise those sentinel nodes accurately, which may shorn overall procedure time and decrease complication levels.
Innovations in lymph node mapping have come mainly from the melanoma and breast cancer field. At present, lymph node mapping in e.g.. the breast is performed with a combination of preoperative 99m-Tc-labeled nano colloid injection and intraoperative injection of blue dyes (e.g. patent blue) for visible guidance.
Preoperative lymphoscintigraphy, using 99m-Tc-labeled nanocolloidal particles, has also demonstrated its use in imaging of the sentinel nodes in the prostate. The intraoperative translation of the radio colloid procedure requires the use of a gamma probe or camera to monitor the transit of the colloid from the injection site to the sentinel node(s). Unfortunately, the applicability of radionuclide-based intraoperative detection remains challenging. Ideally, an extra visual aid, e.g. blue dyes, can help guide the surgeon. However, the dynamics of the conventional blue dye limit its use in prostate cancer.
Recently, several promising new trials have been published for breast, prsotate and gastrointestinal cancer using the near-infrared fluorescent dye indocyanine green (ICG) for intraoperative fluorescence detection of the lymph nodes. in a feasibility study (in breast cancer), the FDA suggested that a cocktail injection of fluorescent and radioactive agents would be preferable over multiple singe injections. In the preclinical setting we have fully optimized this approach in a spontaneous mouse model of prostate cancer.
In our initial feasibility study we showed the use of the hybrid tracer ICG-99mTc-nanocolloid for sentinel node mapping during laparoscopic sentinel node dissection for prostate cancer. Here we showed that with the hybrid tracer we were able to facilitate and optimized dissection of the sentinel nodes during RALP procedures. ICG-99mTc-nanocolloid allowed preoperative surgical planning and intraoperative optical detection of the sentinel nodes. Furthermore it was found that especially when sentinel nodes were located close to the injection site, fluorescence imaging was useful as gamma probe detection was hindered due to the background signal coming from the injection site. In addition to this, the fluorescence signal (which can be detected >3 months after injection in the formalin-fixed paraffin-embedded tissue samples) allowed us to study the influence of the injection site on the observed lymphatic drainage pattern. Fluorescence imaging of these samples suggested that the location where the tracer is injected is of influence on the observed lymphatic drainage pattern.

The addition of fluorescence imaging to the standard radio-guided procedure improves intraoperative sentinel node detection.

Day of surgery.

On the morning of surgery patients will receive an transrectal-ultrasound guided intraprostatic or intratumoral injection with the hybrid tracer ICG-99mTc-nanocolloid. Thereafter, preoperative imaging will be performed: static lymphoscintigraphy (15min and 2hrs p.i.) and SPECT-CT imaging (2hrs p.i.). The nuclear medicine physician will evaluate the images and determine the number and location of the sentinel node(s). Prior to the start of the operation the images are presented to the urologist. Intraoperatively, sentinel nodes are identified via fluorescence imaging (and gamma tracing).