Introduction Previous studies indicated that location and amount of detected sentinel lymph nodes (SLNs) in prostate cancer (PCa) are influenced where SLN-tracer is deposited within the prostate.... Show moreIntroduction Previous studies indicated that location and amount of detected sentinel lymph nodes (SLNs) in prostate cancer (PCa) are influenced where SLN-tracer is deposited within the prostate. To validate whether intratumoral (IT) tracer injection helps to increase identification of tumor-positive lymph nodes (LNs) better than intraprostatic (IP) tracer injection, a prospective randomized phase II trial was performed.Methods PCa patients with a > 5% risk of lymphatic involvement were randomized between ultrasound-guided transrectal injection of indocyanine green-[Tc-99m]Tc-nanocolloid in 2 depots of 1 mL in the tumor (n = 55, IT-group) or in 4 depots of 0.5 mL in the peripheral zone of the prostate (n = 58, IP-group). Preoperative lymphoscintigraphy and SPECT/CT were used to define the location of the SLNs. SLNs were dissected using combination of radio- and fluorescence-guidance, followed by extended pelvic LN dissection and robot-assisted radical prostatectomy. Outcome measurements were number of tumor-bearing SNs, tumor-bearing LNs, removed nodes, number of patients with nodal metastases, and metastasis-free survival (MFS) of 4-7-year follow-up data.Results IT-injection did not result in significant difference of removed SLNs (5.0 vs 6.0, p = 0.317) and histologically positive SLNs (28 vs 22, p = 0.571). However, in IT-group, the SLN-positive nodes were 73.7% of total positive nodes compared to 37.3% in IP-group (p = 0.015). Moreover, significantly more node-positive patients were found in IT-group (42% vs 24%, p = 0.045), which did not result in worse MFS. In two patients (3.6%) from whom the IT-tracer injection only partly covered intraprostatic tumor spread, nodal metastases in ePLND without tumor-positive SNs were yielded.Conclusions The percentage-positive SLNs found after IT-injection were significantly higher compared to IP-injection. Significantly more node-positive patients were found using IT-injection, which did not affect MFS. IT-injection failed to detect nodal metastases from non-index satellite lesions. Therefore, we suggest to combine IT- and IP-tracer injections in men with visible tumor on imaging. Show less
Collamati, F.; Oosterom, M.N. van; Simoni, M. de; Faccini, R.; Fischetti, M.; Terracciano, C.M.; ... ; Morganti, S. 2020
Background Recently, a flexible DROP-IN gamma-probe was introduced for robot-assisted radioguided surgery, using traditional low-energy SPECT-isotopes. In parallel, a novel approach to achieve... Show moreBackground Recently, a flexible DROP-IN gamma-probe was introduced for robot-assisted radioguided surgery, using traditional low-energy SPECT-isotopes. In parallel, a novel approach to achieve sensitive radioguidance using beta-emitting PET isotopes has been proposed. Integration of these two concepts would allow to exploit the use of PET tracers during robot-assisted tumor-receptor-targeted. In this study, we have engineered and validated the performance of a novel DROP-IN beta particle (DROP-IN beta) detector. Methods Seven prostate cancer patients with PSMA-PET positive tumors received an additional intraoperative injection of similar to 70 MBq(68)Ga-PSMA-11, followed by robot-assisted prostatectomy and extended pelvic lymph node dissection. The surgical specimens from these procedures were used to validate the performance of our DROP-IN(beta)probe prototype, which merged a scintillating detector with a housing optimized for a 12-mm trocar and prograsp instruments. Results After optimization of the detector and probe housing via Monte Carlo simulations, the resulting DROP-IN(beta)probe prototype was tested in a robotic setting. In the ex vivo setting, the probe-positioned by the robot-was able to identify(68)Ga-PSMA-11 containing hot-spots in the surgical specimens: signal-to-background (S/B) was > 5 when pathology confirmed that the tumor was located < 1 mm below the specimen surface.Ga-68-PSMA-11 containing (and PET positive) lymph nodes, as found in two patients, were also confirmed with the DROP-IN(beta)probe (S/B > 3). The rotational freedom of the DROP-IN design and the ability to manipulate the probe with the prograsp tool allowed the surgeon to perform autonomous beta-tracing. Conclusions This study demonstrates the feasibility of beta-radioguided surgery in a robotic context by means of a DROP-IN(beta)detector. When translated to an in vivo setting in the future, this technique could provide a valuable tool in detecting tumor remnants on the prostate surface and in confirmation of PSMA-PET positive lymph nodes. Show less
