Magnetometer-Guided Sentinel Lymph Node Dissection in Prostate Cancer: Rate of Lymph Node Involvement Compared with Radioisotope Marking

Abstract

Sentinel pelvic lymph node dissection (sPLND) enables the targeted removal of lymph nodes (LNs) bearing the highest metastasis risk. In prostate cancer (PCa), sPLND alone or combined with extended PLND (ePLND) reveals more LN metastases along with detecting sentinel LNs (SLNs) outside the conventional ePLND template. To overcome the disadvantages of radioisotope-guided sPLND in PCa treatment, magnetometer-guided sPLND applying superparamagnetic iron oxide nanoparticles as a tracer was established. This retrospective study compared the nodal staging ability between magnetometer- and radioisotope-guided sPLNDs. We analyzed data of PCa patients undergoing radical prostatectomy and magnetometer- (848 patients, 2015–2021) or radioisotope-guided (2092 patients, 2006–2015) sPLND. To reduce heterogeneity among cohorts, we performed propensity score matching and compared data considering sentinel nomogram-based probabilities for LN involvement (LNI). Magnetometer- and radioisotope-guided sPLNDs had SLN detection rates of 98.12% and 98.09%, respectively; the former detected more SLNs per patient. The LNI rates matched nomogram-based predictions in both techniques equally well. Approximately 7% of LN metastases were detected outside the conventional ePLND template. Thus, we confirmed the reliability of magnetometer-guided sPLND in nodal staging, with results comparable with or better than radioisotope-guided sPLND. Our findings highlight the importance of the sentinel technique for detecting LN metastases in PCa.

Sentinel Lymph Node Biopsy in Prostate Cancer: An Overview of Diagnostic Performance, Oncological Outcomes, Safety, and Feasibility

“…They described a comparable detection rate (98.18% vs. 98.11%, respectively) [54]. Despite the feasibility of the magnetometer-guided technique, this group underlined some contraindications of the magnetic-guided technique in patients bearing pacemakers or other implanted electronic devices, in cases of iron hypersensitivity as well as in hemochromatosis or other iron overload conditions [54]. Moreover, it should be taken into account that the presence of any metal implant or prosthesis may negatively affect the diagnostic yield of the technique.…”

“…Engels et al presented a retrospective analysis comparing radio-guided SNB and magnetic SNB techniques. They described a comparable detection rate (98.18% vs. 98.11%, respectively) [54]. Despite the feasibility of the magnetometer-guided technique, this group underlined some contraindications of the magnetic-guided technique in patients bearing pacemakers or other implanted electronic devices, in cases of iron hypersensitivity as well as in hemochromatosis or other iron overload conditions [54].…”

The survival benefit of different lymph node yields in radical prostatectomy for pN1M0 prostate cancer patients: Implications from a population-based study

“…Hypogastric and obturator fossa nodal might be removed for all pN1 patients because of their high incidence of metastases. It was critical to identify the positive lymph node before or during surgery; approximately 7% of lymph node metastases were detected outside the conventional extended LND template ( 23 ). We considered the extent of LND evaluated by risk stratification (mainly Gleason score and T stage in our study) outweighed an ELND template for pN1 PCa patients.…”

Sentinel Lymph Node Techniques in Urologic Oncology: Current Knowledge and Application

“…Another promising direction of SLN-centered investigations is the usage of magnetometer-based techniques and SPIONs [109]. The first studies revealed very promising outcomes, although the reliability of magnetometer techniques require further, more thorough studies involving larger cohorts [35,36,110,111].…”