The Establishment of New Thresholds for PLND-Validated Clinical Nomograms to Predict Non-Regional Lymph Node Metastases: Using 68Ga-PSMA PET/CT as References

Abstract

PurposePLND (pelvic lymph node dissection)-validated nomograms are widely accepted clinical tools to determine the necessity of PLND by predicting the metastasis of lymph nodes (LNMs) in pelvic region. However, these nomograms are in lacking of a threshold to predict the metastasis of extrareolar lymph nodes beyond pelvic region, which is not suitable for PLND. The aim of this study is to evaluate a threshold can be set for current clinical PLND-validated nomograms to predict extrareolar LN metastases beyond pelvic region in high-risk prostate cancer patients, by using 68Ga-PSMA PET/CT as a reference to determine LN metastases (LNMs).Experimental DesignWe performed a retrospective analysis of 57 high-risk treatment-naïve PC patients in a large tertiary care hospital in China who underwent 68Ga-PSMA-617 PET/CT imaging. LNMs was detected by 68Ga-PSMA-617 PET/CT and further determined by imaging follow-up after anti-androgen therapy. The pattern of LN metastatic spread of PC patients were evaluated and analyzed. The impact of 68Ga-PSMA PET/CT on clinical decisions based on three clinical PLND-validated nomograms (Briganti, Memorial Sloan Kettering Cancer Center, Winter) were evaluated by a multidisciplinary prostate cancer therapy team. The diagnostic performance and the threshold of these nomograms in predicting extrareolar LNMs metastasis were evaluated via receiver operating characteristic (ROC) curve analysis.ResultsLNMs were observed in 49.1% of the patients by 68Ga-PSMA PET/CT, among which 65.5% of LNMs were pelvic-regional and 34.5% of LNMs were observed in extrareolar sites (52.1% of these were located above the diaphragm). The Briganti, MSKCC and Winter nomograms showed that 70.2%-71.9% of the patients in this study need to receive ePLND according to the EAU and NCCN guidelines. The LN staging information obtained from 68Ga-PSMA PET/CT would have led to changes of planned management in 70.2% of these patients, including therapy modality changes in 21.1% of the patients, which were mainly due to newly detected non-regional LNMs. The thresholds of nomograms to predict non-regional LNMs were between 64% and 75%. The PC patients with a score >64% in Briganti nomogram, a score >75% in MSKCC nomogram and a score >67% in Winter nomogram were more likely to have non-regional LNMs. The AUCs (Area under curves) of the clinical nomograms (Briganti, MSKCC and Winter) in predicting non-regional LNMs were 0.816, 0.830 and 0.793, respectively.ConclusionsBy using 68Ga-PSMA PET/CT as reference of LNM, the PLND-validated clinical nomograms can not only predict regional LNMs, but also predict non-regional LNMs. The additional information from 68Ga-PSMA PET/CT may provide added benefit to nomograms-based clinical decision-making in more than two-thirds of patients for reducing unnecessary PLND. We focused on that a threshold can be set for current clinical PLND-validated nomograms to predict extrareolar LN metastases with an AUC accuracy of about 80% after optimizing the simple nomograms which may help to improve the efficiency for PC therapy significantly in clinical practice.

Analysis of the surgical approach in prostate cancer staging: results from the surveillance, epidemiology and end results program

“…Notwithstanding, a previous study showed that patients with high-risk disease who may benefit from a super-extended PLND can be identified with the nomograms themselves, but with a higher cutoff point in the risk for metastasis when compared to those currently advocated by some guidelines (30% vs. 5% or 7%) 23 , 24 , 27 . Similarly, another study observed that risk greater than 60% better identified patients with benefit from extended PLND, most of whom had non-regional metastasis 28 . Therefore, the present results reinforce the need for a more refined recommendation of the extension of the PLND in function of the risk of lymph node metastasis and, perhaps, intraoperative analysis of the lymph nodes in selected patients in order to perform a super-extended approach when necessary.…”

Prostate-specific membrane antigen-targeted surgery in prostate cancer: Accurate identification, real-time diagnosis, and precise resection

“…For patients with regional LNMs, RP±PLND should be performed. PSMA-PET/CT can be used to exclude patients with distal LNMs (M1a stage), bone metastases (M1b stage), or visceral metastases (M1c stage) from planned curative radical prostatectomy 28 . For LNMs with a diameter ≥2.3 mm, PSMA-PET can achieve a detection rate of 50.0% 29 .…”

Nukleáris medicina a prosztatarák diagnosztikájában és kezelésében (teranosztika)

“…Előbbi szenzitivitása 85, specificitása 98%-osnak adódott, szemben az utóbbi 38 és 91%-os értékeivel (15). A sebészi kezelési tervvel kapcsolatban a PSMA-PET/CT jelentős változáshoz vezethet azon tulajdonságának köszönhetően, hogy kicsi, de PSMA-avid nyirokcsomókat detektálhat a medencerégióban a tervezett beavatkozás kiterjedésén túli területen (16). Definitív sugárkezelés előtt végzett PSMA-PET/CT alkalmazhatónak látszik a domináns intraprosztatikus lézió kijelölésére és a biológiai besugárzási céltérfogat azonosítására, beleértve a konvencionális vizsgálómódszerekkel nem azonosítható nyirokcsomóáttétek tisztázását is (2).…”