RESUMO
Radioisotope-guided sentinel lymph node dissection (sLND) has shown high diagnostic reliability in prostate (PCa) and other cancers. To overcome the limitations of the radioactive tracers, magnetometer-guided sLND using superparamagnetic iron oxide nanoparticles (SPIONs) has been successfully used in PCa. This prospective study (SentiMag Pro II, DRKS00007671) determined the diagnostic accuracy of magnetometer-guided sLND in intermediate- and high-risk PCa. Fifty intermediate- or high-risk PCa patients (prostate-specific antigen (PSA) ≥ 10 ng/mL and/or Gleason score ≥ 7; median PSA 10.8 ng/mL, IQR 7.4-19.2 ng/mL) were enrolled. After the intraprostatic SPIONs injection a day earlier, patients underwent magnetometer-guided sLND and extended lymph node dissection (eLND, followed by radical prostatectomy. SLNs were detected in in vivo and in ex vivo samples. Diagnostic accuracy of sLND was assessed using eLND as the reference. SLNs were detected in all patients (detection rate 100%), with 447 sentinel lymph nodes SLNs (median 9, IQR 6-12) being identified and 966 LNs (median 18, IQR 15-23) being removed. Thirty-six percent (18/50) of patients had LN metastases (median 2, IQR 1-3). Magnetometer-guided sLND had 100% sensitivity, 97.0% specificity, 94.4% positive predictive value, 100% negative predictive value, 0.0% false negative rate, and 3.0% additional diagnostic value (LN metastases only in SLNs outside the eLND template). In vivo, one positive SLN/LN-positive patient was missed, resulting in a sensitivity of 94.4%. In conclusion, this new magnetic sentinel procedure has high accuracy for nodal staging in intermediate- and high-risk PCa. The reliability of intraoperative SLN detection using this magnetometer system requires verification in further multicentric studies.
RESUMO
Background: Accurate histopathological evaluation of lymph nodes (LNs) is essential for reliable staging in prostate cancer. In routine practice, conventional techniques only examine parts of the LN. Molecular nodal staging methods are limited by their high costs and extensive time requirement. One-step nucleic acid amplification (OSNA) determines the metastatic status of the complete LN and allows for rapid intraoperative detection of LN metastases. OSNA has been proposed for diagnosis of LN metastases from breast cancer by quantifying the CK19 mRNA copy number. To provide basic data for OSNA development for prostate cancer, we conducted an investigation of CK19 and OSNA in prostate cancer specimens. Methods: OSNA is based on a short homogenization step and subsequent automated amplification of CK19 mRNA directly from the sample lysate, with results available in 30-40 min. A total of 20 prostate cancer specimens from consecutive patients with intermediate or high-risk prostate cancer (Gleason-Score ≥7) were investigated by both OSNA and conventional histopathology (H&E staining, CK19 immunohistochemistry). OSNA was performed on frozen samples using a ready-to-use amplification kit in an automated real-time detection system. Samples were defined as 'negative' or 'positive' according to mRNA copy number: >5000 copies/µl (++), 250-5000 copies/µl (+), and <250 copies/µl (-). Results: Histopathological analysis confirmed prostate cancer in all samples: Gleason score 7 (n=11), Gleason score 8 (n=2), and Gleason score 9 (n=6). Gleason score could not be given for one patient who previously underwent hormonal treatment. OSNA analysis detected CK19 expression in 100% of the specimens and high numbers of CK19 mRNA copies in all cases (9 samples ++; 11 samples +). Immunohistochemistry confirmed CK19 expression in 19 of 20 cases. In the immunohistochemistry CK19-negative patient, a Gleason score 9 prostate cancer was diagnosed. Conclusions: This is the first study using OSNA to detect CK19 expression in prostate cancer. Initial data indicate that this rapid method for molecular LN staging reliably identifies CK19 mRNA in prostate cancer. These results suggest that the OSNA assay may be suitable to improve (intraoperative) LN staging in prostate cancer. For further verification, OSNA analysis of LN specimens from prostate cancer patients is required.
RESUMO
PURPOSE: Sentinel lymph node (LN) dissection (sLND) using a magnetometer and superpara-magnetic iron oxide nanoparticles (SPION) as a tracer was successfully applied in prostate cancer (PCa). The feasibility of sentinel LN (SLN) visualization on MRI after intraprostatic SPION injection has been reported. In the present study, results of preoperative MRI identification of SLNs and the outcome of subsequent intraoperative magnetometer-guided sLND following intraprostatic SPION injection were studied in intermediate- and high-risk PCa. PATIENTS AND METHODS: A total of 50 intermediate- and high-risk PCa patients (prostate-specific antigen >10 ng/mL and/or Gleason score ≥7) scheduled for radical prostatectomy with magnetometer-guided sLND and extended pelvic LND (eLND), were included. Patients underwent MRI before and one day after intraprostatic SPION injection using T1-, T2-, and T2*-weighted sequences. Diagnostic rate per patient was established. Distribution of SLNs per anatomic region was registered. Diagnostic accuracy of sLND was assessed by using eLND as a reference standard. RESULTS: SPION-MRI identified a total of 890 SLNs (median 17.5; IQR 12-22.5). SLNs could be successfully detected using MRI in all patients (diagnostic rate 100%). Anatomic SLN distribution: external iliac 19.2%, common iliac 16.6%, fossa obturatoria 15.8%, internal iliac 13.8%, presacral 12.1%, perirectal 12.0%, periprostatic 3.7%, perivesical 2.3%, and other regions 4.4%. LN metastases were intraoperatively found in 15 of 50 patients (30%). sLND had a 100% diagnostic rate, 85.7% sensitivity, 97.2% specificity, 92.3% positive predictive value, 94.9% negative predictive value, false negative rate 14.3%, and 2.8% additional diagnostic value (LN metastases only outside the eLND template). CONCLUSION: MR scintigraphy after intraprostatic SPION injection provides a roadmap for intraoperative magnetometer-guided SLN detection and can be useful to characterize a reliable lymphadenectomy template. Draining LN from the prostate can be identified in an unexpectedly high number, especially outside the established eLND template. Further studies are required to analyze discordance between the number of pre- and intraoperatively identified SLNs.
