Sentinel Lymph Node Biopsy for Prostate Cancer: A Hybrid Approach

Abstract

To provide surgeons with optimal guidance during interventions, it is crucial that the molecular imaging data generated in the diagnostic departments finds its way to the operating room. Sentinel lymph node (SLN) biopsy provides a textbook example in which molecular imaging data acquired in the department of nuclear medicine guides the surgical management of patients. For prostate cancer, in which SLNs are generally located deep in the pelvis, procedures are preferably performed via a (robotassisted) laparoscopic approach. Unfortunately, in the laparoscopic setting the senses of the surgeon are reduced. This topical review discusses technologic innovations that can help improve surgical guidance during SLN biopsy procedures. Metastasis in pelvic lymph nodes (LNs) is considered an important prognostic factor in prostate cancer. Prostatespecific antigen levels, pathologic stage, and Gleason score are predictors for LN involvement; the higher these factors are, the greater is the chance of nodal involvement. Postoperative (histo)pathologic examination of tissue samples obtained during (extended) pelvic lymphadenectomy is considered the gold standard in assessing metastatic spread. With an increasing LN dissection template, the prognosis of both N0 and N1 groups increases (Will Rogers phenomenon). Unfortunately, (extended) pelvic lymphadenectomy also increases the chance of postoperative complications such as lymphoceles, injuries to the obturator nerve or the ureter, and lymphedema of the lower extremity. Such complications can lead to a decrease in the patient's quality of life.Sentinel LN (SLN) biopsy focuses on the identification, subsequent minimally invasive excision, and pathologic and histopathologic evaluation of the LNs that drain directly from the primary tumor. Assuming the orderly spread of tumor cells through the lymphatic system, SLN biopsy can be used for LN staging. After staging, therapeutic follow-up can be decided on.The potential of SLN biopsy for detecting LN metastasis has been validated in several studies. The Augsburg group validated the SLN biopsy procedure in more than 2,000 patients with prostate cancer and reported a high sensitivity and an overall false-negative rate of 5.9% (1). Moreover, SLN biopsy allows the identification of SLNs outside the pelvic lymphadenectomy field (2-4). Recently, Joniau et al. showed that 44% of SLNs were located outside the extended pelvic lymphadenectomy field; in 6% of patients, a positive LN was located exclusively in the presacral or paraaortic region (2).Ideally, a surgeon is able to identify and excise the preoperatively identified SLNs in a minimally invasive manner, with a high sensitivity and specificity. This topical review discusses technologic improvements that may help improve the different aspects involved in (robot-assisted) laparoscopic SLN biopsy for prostate cancer; SLN biopsy for the prostate is often performed in combination with laparoscopic radical prostatectomy. Potential improvements can be found in (hybrid) tracers that are radioacti...

Toward (Hybrid) Navigation of a Fluorescence Camera in an Open Surgery Setting

“…To solve these translational issues, and to enable a best-of-both-worlds scenario, a hybrid surgical guidance concept is advocated. This concept is based on integrating multiple complementary features that are of value for preoperative imaging (nuclear medicine) and intraoperative (fluorescence) image-guided surgery (3). This can, in part, be realized using a hybrid tracer that contains 2 distinct signals, for example, the sentinel node (SN) tracer indocyanine green (ICG)-99m Tc-nanocolloid (1).…”

Optical Imaging of Renal Cell Carcinoma with Anti–Carbonic Anhydrase IX Monoclonal Antibody Girentuximab

“…Nontargeted dually labeled tracers were applied for sentinel lymph node biopsy and resection after intratumoral injection of nanocolloid in a clinical setting (20). The results clearly demonstrated improved lymph node detection, especially when positive nodes were located in lymph node-rich regions, as in prostate cancer or head and neck cancer (21,22). A study with patients who had ovarian cancer had already shown the feasibility and potential of this approach for intraoperative fluorescence imaging in a clinical setting (23).…”

New technologies in radioguided surgery in complex anatomic areas

“…As the camera was not connected to the da Vinci SI system, the device was handled by a bedside assistant and not by the surgeon himself. The SLN detection rate of fluorescence guidance was 95.3 % [83]. Using a robotic-integrated laparoscope that was handled by the responsible surgeon, the SLN identification rate did not improve (80.4-85.7 %) [78].…”

“…In both settings, the preoperatively performed SPECT/CT plays an essential role, providing the surgeon with a 3D road map including anatomic structures. However, in the present studies 3D images had to be viewed on a separate DICOM viewer (PACS Vue Solutions, Carestream Health, Rochester, NY, USA) and the surgeon had to leave the da Vinci console during the surgical procedure [78,83]. The next step to an augmented reality view would be fusion of the complementary information provided by preoperative SPECT/CT and intraoperative fluorescence imaging [84,85].…”