Prospective comparison of 18F-PSMA-1007 PET/CT, whole-body MRI and CT in primary nodal staging of unfavourable intermediate- and high-risk prostate cancer

PSMA PET/CT for prostate cancer diagnosis: current applications and future directions

Prostate cancer (PCa) requires improved diagnostic strategies beyond conventional imaging. This review aimed to evaluate the role of prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) in diagnosing advanced PCa. The review analyzed the diagnostic performance of PSMA PET/CT in various clinical contexts, including locoregional staging, extracapsular extension (ECE), seminal vesicle invasion (SVI), pelvic lymph node metastases, distant metastases, and biochemical recurrence (BCR). Further, challenges such as PSMA-negative tumors, need for standardized protocols, and potential of emerging imaging targets (neurotensin receptor 1 and fibroblast activation proteins) were reviewed. The role of artificial intelligence (AI) and advancements in tracer development were explored. PSMA PET/CT demonstrated exceptional specificity for locoregional staging, ECE, and SVI while reducing unnecessary biopsies and optimizing biopsy strategies. The diagnostic accuracy for pelvic lymph node metastases was higher with PSMA PET/CT than with traditional methods, although sensitivity for micrometastasis detection remained challenging. For distant metastases, PSMA PET/CT outperformed bone scintigraphy (BS) and conventional imaging, particularly in identifying bone and atypical lesions. In BCR cases, PSMA PET/CT reliably detected recurrent lesions at low prostate-specific antigen levels, significantly influencing treatment strategies. The review findings indicate that PSMA PET/CT is a superior diagnostic tool for PCa due to its high specificity and accuracy. Despite limitations such as PSMA-negative tumors and sensitivity challenges, advancements in AI, novel imaging targets, and affordable tracer development hold promise for broader clinical adoption. This review underscores the transformative potential of PSMA PET/CT in PCa diagnosis and management, advocating for ongoing research and protocol standardization.

Impact of PSMA PET on Radiation Oncology Planning

Radiation therapy (RT) plays a critical role in managing prostate cancer (PCa) in various stages, from localized disease to metastatic settings. Recent advancements in molecular imaging using prostate-specific membrane antigen positron emission tomography (PSMA-PET) have revolutionized PCa diagnosis, significantly enhancing local, lymph node and distant stagingto conventional imaging methods. This narrative review explores the impact of PSMA-PET on RT planning, highlighting its diagnostic performance and implications for RT treatment management. PSMA-PET has shown superior sensitivity in detecting metastatic lesions and intraprostatic tumor volumes, leading to more accurate disease staging and treatment planning. The HypoFocal trials investigate the safety and efficacy of implementing PSMA-PET into definitive RT regimens. Additionalongoing clinical trials are investigating the potential of PSMA-PET-based RT recurrent and oligometastatic PCa. Despite these advancements, further research is necessary to optimize patient selection and define the best management strategies for PSMA-PET-guided RT.

Prospective comparison of 18F-PSMA-1007 PET/CT and MRI with histopathology as the reference standard for intraprostatic tumour detection and T-staging of high-risk prostate cancer

PURPOSE

To prospectively compare the ability of 18F-PSMA-1007 PET/CT and whole-body MRI (WBMRI) with DWI to detect prostate cancer (PCa) lesions and assess their local stage. Additionally, to evaluate the correlation between PSMA uptake on PET/CT and PSMA expression as assessed by immunohistochemistry.

METHODS

Men with newly diagnosed unfavourable intermediate or high-risk PCa underwent 18F-PSMA-1007 PET/CT and WBMRI with DWI before robot-assisted laparoscopic prostatectomy. Diagnostic accuracy for intraprostatic tumour localization, seminal vesicle invasion (SVI), and extraprostatic extension (EPE) was evaluated using whole-mount prostatectomy specimens as the reference standard. SUVmax was compared with immunohistochemical PSMA staining intensity quantified using QuPath software.

RESULTS

19 patients with 39 intraprostatic lesions in histopathology were included. The overall lesion detection rates for PET/CT were 84.6% and 82.1% for two independent readers, compared to 74.4% and 46.2% for MRI readers. The detection rates of index lesions were 94.7% for PET/CT and 74.0-84.0% for MRI, whereas those of non-index lesions were 70.0-75.0% for PET/CT and 20.0-65.0% for MRI. For detecting EPE, AUC values were 0.500-0.591 for PET/CT and 0.648-0.682 for MRI. For detecting SVI, AUC values ranged from 0.629 to 0.700 across both modalities. SUVmax showed a weak correlation with immunohistochemical expression of PSMA multiplied by lesion diameter (Spearman's ρ = 0.427, p = 0.013). Lesion diameters measured using 30% and 40% of SUVmax, as well as prostate SUVbackground x2, showed the closest agreement with histopathological measurements.

CONCLUSION

18F-PSMA-1007 PET/CT demonstrated high sensitivity in localizing intraprostatic carcinoma lesions but seemed inferior to WBMRI in detecting EPE. PSMA uptake appears to depend on both PSMA expression and lesion size. These findings highlight the complementary roles of PET/CT and MRI in the detection and tumor staging of PCa.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov ID: NCT03537391. Registered 25 May 2018.

Escalating the dose of high-dose-rate brachytherapy combined with external beam radiotherapy improves the disease control rate in patients with high- or very-high-risk prostate cancer

PURPOSE

High-dose-rate brachytherapy (HDR-BT) combined with external beam radiotherapy (EBRT) is an effective treatment for patients with high- and very-high-risk prostate cancer. We sought to identify the factors associated with reduced biochemical recurrence rates following HDR-BT.

METHODS

A total of 304 patients with high- or very-high-risk prostate cancer who underwent HDR-BT and EBRT were analyzed. EBRT comprised 50 Gy in 25 fractions and HDR-BT comprised 18 Gy in 2 fractions. Biochemical recurrence was defined as an increase in prostate specific antigen (PSA) by ≥2.0 ng/mL from the nadir level.

RESULTS

The median follow-up time was 8.2 years (range, 3.4‒13.7 years) after HDR-BT. The 5-year biochemical progression-free survival (bPFS), overall survival, and cause-specific survival rates were 87.4%, 93.3%, and 100%, respectively. In univariate and multivariable analyses, a biologically effective dose (α/β = 1.5) ≥ 240 Gy and androgen deprivation therapy (ADT) were significantly associated with better bPFS (p = 0.020 and 0.007, respectively), whereas pretreatment PSA ≥ 40 ng/mL and Gleason score group 5 were significantly associated with worse bPFS (p = 0.080 and 0.021, respectively). Grade ≥ 3 rectal toxicities occurred in 0.3% of patients and grade ≥ 3 urinary toxicities occurred in 3.4% of patients.

CONCLUSION

In patients with high- and very-high-risk prostate cancer treated with EBRT and HDR-BT, dose escalation and ADT were associated with improved tumor control. By comparison, Gleason score group 5 and pretreatment PSA >40 ng/mL were associated with worse tumor control.

Whole-body MRI for staging prostate cancer: a narrative review

OBJECTIVE

To present a narrative review regarding the diagnostic accuracy of whole-body magnetic resonance imaging (WBMRI) in staging patients with high-risk prostate cancer (HRPCa) and compare it to established imaging modalities.

METHODS

A narrative review was carried out using PubMed using the following keywords: 'whole body', 'magnetic resonance imaging', 'MRI', 'prostate cancer', 'risk stratification', and 'staging'. Articles that evaluated WBMRI as the imaging modality to stage patients with HRPCa were included, while studies that solely assessed for biochemical recurrence or metastatic disease progression were excluded.

RESULTS

In the evaluation of lymphatic metastases, WBMRI has demonstrated a comparable, if not improved, sensitivity and specificity compared to conventional imaging of computed tomography (CT). Furthermore, WBMRI demonstrates improved sensitivity and specificity in detecting bone metastases compared to bone scintigraphy (BS). However, with advent of prostate-specific membrane antigen (PSMA) radioligands for positron emission tomography (PET), the diagnostic performance of WBMRI to detect metastatic disease appears inferior.

CONCLUSIONS

The diagnostic capabilities of WBMRI exceed that of conventional imaging of CT and BS in detecting metastatic disease in patients with HRPCa. However, WBMRI does not perform as well as PSMA PET/CT. Further study on cost comparisons between WBMRI and PSMA PET/CT are needed, as well as evaluations of combined PSMA PET/MRI are needed.

Comparative Performance of 68Ga-PSMA-11 PET/CT and Conventional Imaging in the Primary Staging of High-Risk Prostate Cancer Patients Who Are Candidates for Radical Prostatectomy

This prospective study aimed to (1) compare the diagnostic performance of 68Ga-PSMA-11 PET/CT with respect to conventional imaging (computed tomography (CT) and bone scintigraphy (BS)) in the primary staging of high-risk prostate cancer (PCa) patients and (2) validate PSMA-PET/CT accuracy in pelvic nodal staging in comparison with postoperative histopathology and assess PSMA-PET/CT's impact on patient management. Sixty castration-sensitive high-risk (ISUP 4-5 and/or PSA > 20 ng/mL and/or cT3) PCa patients eligible for radical prostatectomy were enrolled (median PSA 10.10 [IQR: 6.22-17.95] ng/mL). PSMA-PET/CT, compared with CT, identified nodal (N) and/or distant metastases (M1) in 56.7% (34/60) vs. 13.3% (8/60) (p < 0.001) of patients: N + 45% vs. 13.3% (p < 0.001), M1a 11.7% vs. 1.7% (p = 0.03), M1b 23.3% vs. 1.7% (p < 0.001). Compared with BS, PSMA-PET/CT localized unknown skeletal metastases in 15% (9/60) of cases, with no false negative findings. Overall, PSMA-PET/CT led to a TNM upstaging in 45.0% (27/60) of cases, with no evidence of downstaging, resulting in a change in management in up to 28.8% (17/59) of patients. Compared with histopathology data (n = 32 patients), the per-patient accuracy of PSMA-PET/TC for detecting pelvic nodal metastases was 90.6%. Overall, the above evidence supports the use of PSMA-PET/CT in the diagnostic workup of high-risk prostate cancer staging.

Multiparametric Whole-Body MRI: A Game Changer in Metastatic Prostate Cancer

Prostate cancer ranks among the most prevalent tumours globally. While early detection reduces the likelihood of metastasis, managing advanced cases poses challenges in diagnosis and treatment. Current international guidelines support the concurrent use of 99Tc-Bone Scintigraphy and Contrast-Enhanced Chest and Abdomen CT for the staging of metastatic disease and response assessment. However, emerging evidence underscores the superiority of next-generation imaging techniques including PSMA-PET/CT and whole-body MRI (WB-MRI). This review explores the relevant scientific literature on the role of WB-MRI in metastatic prostate cancer. This multiparametric imaging technique, combining the high anatomical resolution of standard MRI sequences with functional sequences such as diffusion-weighted imaging (DWI) and bone marrow relative fat fraction (rFF%) has proved effective in comprehensive patient assessment, evaluating local disease, most of the nodal involvement, bone metastases and their complications, and detecting the increasing visceral metastases in prostate cancer. It does have the advantage of avoiding the injection of contrast medium/radionuclide administration, spares the patient the exposure to ionizing radiation, and lacks the confounder of FLARE described with nuclear medicine techniques. Up-to-date literature regarding the diagnostic capabilities of WB-MRI, though still limited compared to PSMA-PET/CT, strongly supports its widespread incorporation into standard clinical practice, alongside the latest nuclear medicine techniques.

Diagnostic Accuracy of Molecular Imaging Techniques for Detecting Prostate Cancer: A Systematic Review

Molecular imaging modalities show valuable non-invasive techniques capable of precisely and selectively addressing molecular markers associated with prostate cancer (PCa). This systematic review provides an overview of imaging markers utilized in positron emission tomography (PET) methods, specifically focusing on the pathways and mediators involved in PCa. This systematic review aims to evaluate and analyse existing literature on the diagnostic accuracy of molecular imaging techniques for detecting PCa. The PubMed, EBSCO, ScienceDirect, and Web of Science databases were searched, identifying 32 studies that reported molecular imaging modalities for detecting PCa. Numerous imaging modalities and radiotracers were used to detect PCa, including 68Ga-prostate-specific membrane antigen (PSMA) PET/computed tomography (CT), 68Ga-PSMA-11 PET/magnetic resonance imaging (MRI), 18F-PSMA-1007 PET/CT, 18F-DCFPyL PET/MRI, 18F-choline PET/MRI, and 18F-fluoroethylcholine PET/MRI. Across 11 studies, radiolabelled 68Ga-PSMA PET/CT imaging had a pooled sensitivity of 80 (95% confidence interval [CI]: 35-93), specificity of 90 (95% CI: 71-98), and accuracy of 86 (95% CI: 64-96). The PSMA-ligand 68Ga-PET/CT showed good diagnostic performance and appears promising for detecting and staging PCa.

Diagnostic Accuracy of 18F-Prostate Specific Membrane Antigen (PSMA) PET/CT Radiotracers in Staging and Restaging of Patients With High-Risk Prostate Cancer or Biochemical Recurrence: An Overview of Reviews

The aim of this overview was to consolidate existing evidence syntheses and provide a comprehensive overview of the evidence for 18F-prostate specific membrane antigen (PSMA) PET/CT in the staging of high-risk prostate cancer and restaging after biochemical recurrence. An overview of reviews was performed and reported in line with the preferred reporting items for overview of reviews (PRIOR) statement and synthesis without meta-analysis (SWiM) reporting guidelines. A comprehensive database and grey literature search were conducted up to July 18, 2023. Systematic reviews were assessed using the risk of bias in systematic reviews (ROBIS) tool. The certainty of the evidence was assessed using grading of recommendations, assessment, development and evaluations (GRADE). 11 systematic reviews were identified; 10 were at high or unclear risk of bias. Evidence reported on a per-patient, per-lymph node, and per-lesion basis for sensitivity, specificity and overall accuracy was identified. There was a lack of data on dose, adverse events and evidence directly comparing 18F-PSMA PET/CT to other imaging modalities. Evidence with moderate to very low certainty indicated high sensitivity, specificity and accuracy of 18F-PSMA PET/CT in patients with high-risk prostate cancer and biochemical recurrence. There was considerably lower certainty evidence and greater variability in effect estimates for outcomes for the combined intermediate/high-risk cohort. While evidence gaps remain for some outcomes, and most systematic reviews were at high or unclear risk of bias, the current evidence base is broadly supportive of 18F-PSMA PET/CT imaging in the staging and restaging of patients with high-risk prostate cancer and biochemical recurrence.

18 F-prostate specific membrane antigen positron emission tomography/computerized tomography for lymph node staging in medium/high risk prostate cancer: A systematic review and meta-analysis

BACKGROUND

Lymph node staging of prostate cancer (PCa) is important for planning and monitoring of treatment. 18 F-prostate specific membrane antigen positron emission tomography/computerized tomography ( 18 F-PSMA PET/CT) has several advantages over 68 Ga-PSMA PET/CT, but its diagnostic value requires further investigation. This meta-analysis focused on establishing the diagnostic utility of 18 F-PSMA PET/CT for lymph node staging in medium/high-risk PCa.

METHODS

We searched the EMBASE, PubMed, Cochrane library, and Web of Science databases from inception to October 1, 2022. Prostate cancer, 18 F, lymph node, PSMA, and PET/CT were used as search terms and the language was limited to English. We additionally performed a manual search using the reference lists of key articles. Patients and study characteristics were extracted and the QUADAS-2 tool was employed to evaluate the quality of included studies. Sensitivity, specificity, the positive and negative likelihood ratio (PLR and NLR), diagnostic odds ratio (DOR), area under the curve (AUC), and 95% confidence interval (CI) were used to evaluate the diagnostic value of 18 F-PSMA PET/CT. Stata 17 software was employed for calculation and statistical analyses.

RESULTS

A total of eight diagnostic tests including 734 individual samples and 6346 lymph nodes were included in this meta-analysis. At the patient level, the results of each consolidated summary were as follows: sensitivity of 0.57 (95% CI 0.39-0.73), specificity of 0.95 (95% CI 0.92-0.97), PLR of 11.2 (95% CI 6.6-19.0), NLR of 0.46 (95% CI 0.31-0.68), DOR of 25 (95% CI 11-54), and AUC of 0.94 (95% CI 0.92-0.96). At the lesion level, the results of each consolidated summary were as follows: sensitivity of 0.40 (95% CI 0.21-0.62), specificity of 0.99 (95% CI 0.95-1.00), PLR of 40.0 (95% CI 9.1-176.3), NLR of 0.61 (95% CI 0.42-0.87), DOR of 66 (95% CI 14-311), and AUC of 0.86 (95% CI 0.83-0.89).

CONCLUSIONS

18 F-PSMA PET/CT showed moderate sensitivity but high specificity in lymph node staging of medium/high-risk PCa. The diagnostic efficacy was almost equivalent to that reported for 68 Ga-PSMA PET/CT.

REGISTRATION

International Prospective Register of Systematic Reviews (PROSPERO), No. CRD42023391101.

De-Escalation of Therapy for Prostate Cancer

Prostate cancer (PCa) is the second most commonly diagnosed cancer in men with around 1.4 million new cases every year. In patients with localized disease, management options include active surveillance (AS), radical prostatectomy (RP; with or without pelvic lymph node dissection), or radiotherapy to the prostate (with or without pelvic irradiation) with or without hormonotherapy. In advanced disease, treatment options include systemic treatment(s) and/or treatment to primary tumour and/or metastasis-directed therapies (MDTs). Specifically, in advanced stage, the current trend is earlier intensification of treatment such as dual or triple combination systemic treatments or adding treatment to primary and MDT to systemic treatment. However, earlier treatment intensification comes with the cost of increased morbidity and mortality resulting from drug-/treatment-related side effects. The main goal is and should be to provide the best possible care and oncologic outcomes with minimum possible side effects. This chapter will explore emerging possibilities to de-escalate treatment in PCa driven by enhanced insights into disease biology and the natural course of PCa such as AS in intermediate-risk disease or salvage versus adjuvant radiotherapy in post-RP patients. Considerations arising from advancements in PCa imaging and technological advancements in surgical and radiation therapy techniques including omitting pelvic lymph node dissection in the era of prostate-specific membrane antigen positron emitting tomography, the potential of MDT to delay/omit systemic treatment in metachronous oligorecurrence, and the efficacy of hypofractionation schemes compared with conventional fractionated radiotherapy will be discussed.

Diagnostic performance of 18F-labeled PSMA PET/CT in patients with biochemical recurrence of prostate cancer: a systematic review and meta-analysis

BACKGROUND

After initial treatment of prostate cancer, increases in prostate-specific antigen (PSA) levels commonly signify potential relapse or metastasis. 18F-labeled prostate-specific membrane antigen (PSMA) is considered a promising treatment due to its favorable physical properties.

PURPOSE

To investigate the diagnostic value of 18F-PSMA PET/CT for the recurrence and/or metastasis of biochemical recurrence of prostate cancer (BRPca).

MATERIAL AND METHODS

A comprehensive literature search was conducted in PubMed, EMBASE, Web of Science, and the Cochrane Library databases. Combined sensitivity and specificity values for the use of 18F-PSMA PET/CT in patients with BRPca were obtained. The quality of the studies was tested using the Diagnostic Accuracy Research Quality Assessment tool. Meta-analysis was performed using STATA 15 software, and heterogeneity was subsequently tested.

RESULTS

A total of 16 studies (1162 patients) were enrolled and had significant heterogeneity. The pooled sensitivity, specificity, and AUC values for 18F-PSMA PET/CT in the diagnosis of prostate recurrence and/or metastasis were 0.93 (0.89-0.95), 0.94 (0.85-0.98), and 0.96 (0,94-0.98), respectively. Meta-regression analyses showed that the sources of heterogeneity did not relate to ligands, study designs, or participants. The pooled sensitivity and specificity values of 18F-DCFPyL PET/CT were 0.90 (0.85-0.94) and 0.89 (0.85-0.93), respectively. The pooled sensitivity and specificity values of 18F-PSMA-1007 PET/CT were 0.89 (0.85-0.93) and 0.93 (0.70-0.99), respectively. The per-patient pooled sensitivity and specificity values were 0.92 (0.86-0.96) and 0.83 (0.41-0.97), respectively. The per-lesion pooled sensitivity and specificity values were 0.91 (0.86-0.94) and 0.91 (0.86-0.94), respectively.

CONCLUSION

According to our meta-analysis, 18F-PSMA PET/CT has the potential to be critical for the diagnosis of recurrence and/or metastasis in patients with BRPca.

Head-to-head Comparison of the Diagnostic Accuracy of Prostate-specific Membrane Antigen Positron Emission Tomography and Conventional Imaging Modalities for Initial Staging of Intermediate- to High-risk Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Whether prostate-specific membrane antigen positron emission tomography (PSMA-PET) should replace conventional imaging modalities (CIM) for initial staging of intermediate-high risk prostate cancer (PCa) requires definitive evidence on their relative diagnostic abilities.

OBJECTIVE

To perform head-to-head comparisons of PSMA-PET and CIM including multiparametric magnetic resonance imaging (mpMRI), computed tomography (CT) and bone scan (BS) for upfront staging of tumour, nodal, and bone metastasis.

EVIDENCE ACQUISITION

A search of the PubMed, EMBASE, CENTRAL, and Scopus databases was conducted from inception to December 2021. Only studies in which patients underwent both PSMA-PET and CIM and imaging was referenced against histopathology or composite reference standards were included. Quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) checklist and its extension for comparative reviews (QUADAS-C). Pairwise comparisons of the sensitivity and specificity of PSMA-PET versus CIM were performed by adding imaging modality as a covariate to bivariate mixed-effects meta-regression models. The likelihood ratio test was applied to determine whether statistically significant differences existed.

EVIDENCE SYNTHESIS

A total of 31 studies (2431 patients) were included. PSMA-PET/MRI was more sensitive than mpMRI for detection of extra-prostatic extension (78.7% versus 52.9%) and seminal vesicle invasion (66.7% versus 51.0%). For nodal staging, PSMA-PET was more sensitive and specific than mpMRI (73.7% versus 38.9%, 97.5% versus 82.6%) and CT (73.2% versus 38.5%, 97.8% versus 83.6%). For bone metastasis staging, PSMA-PET was more sensitive and specific than BS with or without single-photon emission computerised tomography (98.0% versus 73.0%, 96.2% versus 79.1%). A time interval between imaging modalities >1 month was identified as a source of heterogeneity across all nodal staging analyses.

CONCLUSIONS

Direct comparisons revealed that PSMA-PET significantly outperforms CIM, which suggests that PSMA-PET should be used as a first-line approach for the initial staging of PCa.

PATIENT SUMMARY

We reviewed direct comparisons of the ability of a scan method called PSMA-PET (prostate-specific membrane antigen positron emission tomography) and current imaging methods to detect the spread of prostate cancer outside the prostate gland. We found that PSMA-PET is more accurate for detection of the spread of prostate cancer to adjacent tissue, nearby lymph nodes, and bones.

Preoperative evaluation of prostate cancer by 68Ga-PMSA positron emission tomography/computed tomography: comparison with magnetic resonance imaging and with histopathological findings

Objective

To evaluate the accuracy of preoperative positron emission tomography/computed tomography with 68Ga-labeled prostate-specific membrane antigen (68Ga-PSMA PET/CT) for staging prostate cancer and compare it with magnetic resonance imaging (MRI) using histopathology of surgical specimens as the gold standard.

Materials and Methods

In this retrospective study, 65 patients with prostate cancer were analyzed.

Results

The accuracy of 68Ga-PSMA PET/CT for tumor detection was 95%, and that of MRI was 91%. There was no difference between 68Ga-PSMA PET/CT and MRI regarding localization of the lesion. The sensitivity of 68Ga-PSMA PET/CT for detecting extraprostatic extension was quite low (14%). For detection of seminal vesicle invasion, 68Ga-PSMA PET/CT showed a sensitivity of 57% and accuracy of 91%. There was a moderate correlation between the maximum standardized uptake value (SUVmax) and the serum level of prostate-specific antigen (p < 0.01; ρ = 0.368) and between the SUVmax and the International Society of Urological Pathology (ISUP) grade (p < 0.01; ρ = 0.513).

Conclusion

68Ga-PSMA PET/CT is a promising tool for detecting and evaluating the primary tumor, which can alter the staging and management of the disease.

Head-to-Head Comparison of 68 Ga-P16-093 and 68 Ga-PSMA-617 PET/CT in Patients With Primary Prostate Cancer : A Pilot Study

PURPOSE

We aimed to compare the diagnostic performance of 68 Ga-P16-093 and 68 Ga-PSMA-617 PET/CT in primary prostate cancer (PCa) patients.

PATIENTS AND METHODS

Thirty untreated primary PCa patients were enrolled. Each patient underwent 68 Ga-P16-093 and 68 Ga-PSMA-617 PET/CT within a week. In addition to visual analysis, SUV was measured for semiquantitative comparison and correlation analysis.

RESULTS

68 Ga-P16-093 PET/CT detected more positive tumors than 68 Ga-PSMA-617 PET/CT (67 vs 56, P = 0.002), especially for intraprostatic lesions (29 vs 24, P = 0.025) and lymph node metastases (23 vs 17, P = 0.034). Further, 68 Ga-P16-093 PET/CT exhibited significantly higher SUV max of matched tumors (18.3 ± 14.4 vs 13.9 ± 11.8, P < 0.001). Besides, the SUV max of high-risk patients (based on D'Amico classification) on 68 Ga-P16-093 PET/CT was significantly higher than that of low- and intermediate-risk PCa patients (20.9 ± 9.9 vs 8.9 ± 9.1 vs 10.1 ± 5.2, P = 0.007). The SUV max of tumor measured by 68 Ga-P16-093 PET/CT had a moderate association with biopsy Gleason score ( r = 0.462, P = 0.005) and prostate-specific antigen value ( r = 0.491, P = 0.002), and significantly correlated with PSMA expression ( r = 0.732, P < 0.001).

CONCLUSIONS

68 Ga-P16-093 PET/CT exhibited higher tumor uptake and potentially better tumor detection capability than 68 Ga-PSMA-617 PET/CT, which suggested that 68 Ga-P16-093 may be more suitable in the diagnosis and staging of primary PCa patients.

Comparison of 18 F-PSMA-1007 PET/CT With 68 Ga-PSMA-11 PET/CT for Initial Staging in Intermediate- and High-Risk Prostate Cancer

PURPOSE

This study aimed to compare 18 F-PSMA-1007 PET/CT with 68 Ga-PSMA-11 PET/CT for initial staging in intermediate- and high-risk prostate cancer (PCa) patients.

METHODS

Forty treatment-naive, biopsy-proven, intermediate- or high-risk PCa patients were prospectively recruited. Each patient underwent PET/CT with 68 Ga-PSMA-11 and 18 F-PSMA-1007 (within 2 weeks). Assessment of both set of images included delineating number and characteristics of lesions, measurement of tracer uptake (SUV max ), miPSMA scoring, and PET-based stage categorization.

RESULTS

Intraprostatic lesions were detected in all patients by both tracers with concordant PET-based T stage. Median SUV max of the dominant PSMA-positive prostatic lesions was not significantly different with 18 F-PSMA-1007 and 68 Ga-PSMA-11 (19.9 vs 19.4, P = 0.127, n = 40). Prostatic miPSMA scores were similar in 31/40 (77.5%) patients with both tracers (weighted κ = 0.71). In 23/40 (57.5%) patients, regional lymph nodes (n = 171) were detected by both tracers. Few additional PET-positive regional lymph nodes (n = 3) were exclusively detected by 18 F-PSMA in 2 patients without altering PET-based N stage. Extraregional lymph nodes (n = 123 in 17/40 patients) and visceral metastatic lesions (n = 18 in 3/40 patients) were detected concordantly by both tracers. PET-positive marrow based and skeletal metastases (n = 71) were detected in 14/40 (35%) patients by both tracers. Few additional marrow and skeletal lesions (n = 7) were exclusively detected on 18 F-PSMA-1007 in 5/14 patients, potentially upstaging PET-based M stage in 2/5 patients. Both radiotracers showed excellent interreader agreement for region-wise detection of lesions.

CONCLUSIONS

Our results suggest that 18 F-PSMA-1007 PET/CT is comparable to 68 Ga-PSMA-11 PET/CT in detecting primary and metastatic lesions of PCa.

The Detection Performance of 18 F-Prostate-Specific Membrane Antigen-1007 PET/CT in Primary Prostate Cancer : A Systemic Review and Meta-analysis

BACKGROUND

Multiple tools are now available to determine the requirement for a biopsy to diagnose prostate cancer, and PET/CT with radiolabeled prostate-specific membrane antigen (PSMA)-targeting radiotracers has been recommended for detecting primary prostate cancer. Particularly, the radiotracer 18 F-PSMA-1007 was found to be more favorable for primary tumors compared with other PSMA-targeting radiotracers because of its low clearance via the urinary tract and better image resolution. Thus, we performed a systematic review and meta-analysis to more accurately evaluate the detection performance of 18 F-PSMA-1007 PET/CT in primary prostate cancer patients.

METHODS

An update on the databases of PubMed/MEDLINE, EMBASE, and Cochrane Library for comprehensive literature search was performed on September 30, 2021. The pooling detection rate was calculated on a per-patient basis. The pooling median of the SUV max was analyzed from the included studies. Furthermore, the positive predictive value of 18 F-PSMA-1007 PET/CT with pathologic lesions was analyzed using the criterion standard.

RESULTS

Twelve studies (540 patients total) were included in the meta-analysis. The overall pooling detection rate of 18 F-PSMA-1007 per patient was 94%, and the pooling median of SUV max located at the intraprostate tumor was 16 (range, 3.7-77.7). The positive predictive value of 18 F-PSMA-1007 per lesion with histopathological validation was 0.90, detecting regional lymph node metastasis was 0.94, and detecting localized prostatic tumors was 0.84.

CONCLUSIONS

In the current meta-analysis, we revealed the excellent performance of 18 F-PSMA-1007 to detect localized prostatic tumor lesions and regional lymph node metastasis. Moreover, the uptake of localized tumors in primary prostate cancer was nearly liver uptake and may be considered a suspicious malignancy if it was equal to or greater than the liver uptake.

Head-To-Head Comparison of 68Ga-PSMA-11 PET/CT and 99mTc-MDP Bone Scintigraphy for the Detection of Bone Metastases in Patients With Prostate Cancer: A Meta-Analysis

BACKGROUND. Bone scintigraphy (BS) using 99mTc-labeled methylene diphospho-nate (99mTc-MDP) remains the recommended imaging modality for the detection of bone metastases in patients with prostate cancer (PCa). However, PET/CT using prostate-specific membrane antigen (PSMA) ligands is increasingly recognized as a means of evaluating disease extent in patients with PCa, including use as a possible stand-alone test in high-risk patients. OBJECTIVE. The purpose of this study is to compare the diagnostic performance of 68Ga-PSMA-11 PET/CT with that of 99mTc-MDP BS for the detection of bone metastases in patients with PCa. EVIDENCE ACQUISITION. The PubMed, Embase, and Cochrane Library databases were searched through October 2021 to identify studies reporting a head-to-head comparison of 68Ga-PSMA-11 PET/CT and 99mTc-MDP BS for the detection of bone metastases in patients with PCa. Only studies with a well-defined reference standard (including various combinations of imaging and/or clinical follow-up) were included. Pooled diagnostic performance was calculated using a bivariate random-effects model, and an AUC was derived for each test from hierarchic summary ROC analysis. The complementary roles of the two tests in identifying bone metastases in patients in whom one of the tests was negative were summarized. EVIDENCE SYNTHESIS. Six studies with 546 patients were included. Pooled sensitivity and specificity, respectively, were 98% (95% CI, 94-99%) and 97% (95% CI, 91-99%) for 68Ga-PSMA-11 PET/CT versus 83% (95% CI, 69-91%) and 68% (95% CI, 41-87%) for 99mTc-MDP BS. The AUC was 0.99 (95% CI, 0.96-1.00) for 68Ga-PSMA-11 PET/CT and 0.85 (95% CI, 0.81-0.87) for 99mTc-MDP BS. Among 408 patients from five included studies, 68Ga-PSMA-11 PET/CT correctly identified bone metastases in 43 of 193 patients (22.3%) with negative 99mTc-MDP BS results, whereas 99mTc-MDP BS correctly identified bone metastases in four of 210 patients (1.9%) with negative 68Ga-PSMA-11 PET/CT results. CONCLUSION. On a per-patient basis, the diagnostic performance of 68Ga-PSMA-11 PET/CT is superior to that of 99mTc-MDP BS for the detection of PCa bone metastases. Furthermore, 99mTc-MDP BS offers limited additional information in patients with negative 68Ga-PSMA-11 PET/CT results. CLINICAL IMPACT. According to current evidence, 99mTc-MDP BS is highly unlikely to be additive to 68Ga-PSMA-11 PET/CT in identifying bone metastases in patients with PCa.

The Role of PSMA PET/CT in the Primary Diagnosis and Follow-Up of Prostate Cancer-A Practical Clinical Review

Simple Summary

The combination of positron emission tomography (PET)-diagnostics with ligands binding to the prostate-specific membrane antigen (PSMA) has been a diagnostic milestone in the situation of biochemical recurrence of prostate cancer and is gaining importance in primary diagnostics, providing a highly specific and sensitive diagnostic method in various clinical situations. However, the clinical application of this method requires a comprehensive knowledge of its advantages and disadvantages, potential pitfalls and influencing factors. This review aims to provide a practical clinical review of the currently available background data on PSMA PET/CT, as well as the clinical implications. Although a large amount of data already exist, a thorough analysis is complicated by study heterogeneity, showing the need for future systematic and prospective research.

Abstract

The importance of PSMA PET/CT in both primary diagnostics and prostate cancer recurrence has grown steadily since its introduction more than a decade ago. Over the past years, a vast amount of data have been published on the diagnostic accuracy and the impact of PSMA PET/CT on patient management. Nevertheless, a large heterogeneity between studies has made reaching a consensus difficult; this review aims to provide a comprehensive clinical review of the available scientific literature, covering the currently known data on physiological and pathological PSMA expression, influencing factors, the differences and pitfalls of various tracers, as well as the clinical implications in initial TNM-staging and in the situation of biochemical recurrence. This review has the objective of providing a practical clinical overview of the advantages and disadvantages of the examination in various clinical situations and the body of knowledge available, as well as open questions still requiring further research.

Detection rate of fluorine-18 prostate-specific membrane antigen-1007 PET/CT for prostate cancer in primary staging and biochemical recurrence with different serum PSA levels: A systematic review and meta-analysis

Background

We performed a systematic review and meta-analysis to evaluate the detection rate (DR) of fluoro-prostate-specific membrane antigen (¹⁸F-PSMA-1007) PET/CT in patients with different serum prostate-specific antigen (PSA) levels in the setting of primary staging of prostate cancer (PCa) or biochemically recurring PCa.

Methods

A comprehensive electronic literature search of the PubMed, Embase, and Cochrane Library databases was conducted in accordance with the PRISMA statement. This study was registered in the PROSPERO database (registration number: CRD42022331595). We calculated the DR of ¹⁸F-PSMA-1007 PET/CT in PCa.

Results

The final analysis included 15 studies that described 1,022 patients and 2,034 lesions with ¹⁸F-PSMA-1007 PET/CT in PCa. The DR of ¹⁸F-PSMA-1007 PET/CT in patients with PCa in primary staging ranged from 90% to 100%, with a pooled estimate of 94% (95% CI: 92%–96%). The DR of ¹⁸F-PSMA-1007 PET/CT in patients with PCa in BCR ranged from 47% to 100%, with a pooled estimate of 86% (95% CI: 76%–95%). The DRs of PSA levels >2.0, 1.1–2.0, 0.51–1.0, and ≤0.5 ng/ml detected by ¹⁸F-PSMA-1007 PET/CT in a patient-based analysis were 97% (95% CI: 93%–99%), 95% (95% CI: 88%–99%), 79% (95% CI: 68%–88%), and 68% (95% CI: 58%–78%), respectively.

Conclusion

This meta-analysis concluded that ¹⁸F-PSMA-1007 PET/CT had a high application value for prostate cancer, including primary tumors and biochemical recurrence. The DR of ¹⁸F-PSMA-1007 PET/CT was slightly higher in primary prostate tumors than in biochemical recurrence.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022331595.

Management of Patients with Advanced Prostate Cancer: Report from the Advanced Prostate Cancer Consensus Conference 2021

BACKGROUND

Innovations in treatments, imaging, and molecular characterisation in advanced prostate cancer have improved outcomes, but various areas of management still lack high-level evidence to inform clinical practice. The 2021 Advanced Prostate Cancer Consensus Conference (APCCC) addressed some of these questions to supplement guidelines that are based on level 1 evidence.

OBJECTIVE

To present the voting results from APCCC 2021.

DESIGN, SETTING, AND PARTICIPANTS

The experts identified three major areas of controversy related to management of advanced prostate cancer: newly diagnosed metastatic hormone-sensitive prostate cancer (mHSPC), the use of prostate-specific membrane antigen ligands in diagnostics and therapy, and molecular characterisation of tissue and blood. A panel of 86 international prostate cancer experts developed the programme and the consensus questions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The panel voted publicly but anonymously on 107 pre-defined questions, which were developed by both voting and non-voting panel members prior to the conference following a modified Delphi process.

RESULTS AND LIMITATIONS

The voting reflected the opinions of panellists and did not incorporate a standard literature review or formal meta-analysis. The answer options for the consensus questions received varying degrees of support from panellists, as reflected in this article and the detailed voting results reported in the Supplementary material.

CONCLUSIONS

These voting results from a panel of experts in advanced prostate cancer can help clinicians and patients to navigate controversial areas of management for which high-level evidence is scant. However, diagnostic and treatment decisions should always be individualised according to patient characteristics, such as the extent and location of disease, prior treatment(s), comorbidities, patient preferences, and treatment recommendations, and should also incorporate current and emerging clinical evidence and logistic and economic constraints. Enrolment in clinical trials should be strongly encouraged. Importantly, APCCC 2021 once again identified salient questions that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference is a forum for discussing current diagnosis and treatment options for patients with advanced prostate cancer. An expert panel votes on predefined questions focused on the most clinically relevant areas for treatment of advanced prostate cancer for which there are gaps in knowledge. The voting results provide a practical guide to help clinicians in discussing treatment options with patients as part of shared decision-making.

Radiolabeled PSMA Inhibitors

PSMA has shown to be a promising target for diagnosis and therapy (theranostics) of prostate cancer. We have reviewed developments in the field of radio- and fluorescence-guided surgery and targeted photodynamic therapy as well as multitargeting PSMA inhibitors also addressing albumin, GRPr and integrin αvβ3. An overview of the regulatory status of PSMA-targeting radiopharmaceuticals in the USA and Europe is also provided. Technical and quality aspects of PSMA-targeting radiopharmaceuticals are described and new emerging radiolabeling strategies are discussed. Furthermore, insights are given into the production, application and potential of alternatives beyond the commonly used radionuclides for radiolabeling PSMA inhibitors. An additional refinement of radiopharmaceuticals is required in order to further improve dose-limiting factors, such as nephrotoxicity and salivary gland uptake during endoradiotherapy. The improvement of patient treatment achieved by the advantageous combination of radionuclide therapy with alternative therapies is also a special focus of this review.

[Imaging of oligometastatic disease in selected urologic cancers]

BACKGROUND

Local treatment of the primary or metastatic sites in urologic malignancies is promising when compared to systemic therapy alone, leading to the definition of a potentially curative oligometastatic state.

OBJECTIVES

Comparison of imaging modalities regarding local and metastatic tumor sites in urologic cancers.

METHODS

Review of comparative trials addressing quality criteria of imaging modalities.

RESULTS

Depending on primary tumor and metastatic site, conventional imaging modalities such as computer tomography (CT) and bone scintigraphy still represent the standard of care in Germany. Due to superior quality criteria, hybrid-imaging techniques were widely adopted for oncological staging and particular due to the new PSMA-ligand (PSMA-PET/CT) in prostate cancer imaging. The development of new radioisotopes as well as their clinical application remains a focus of current research.

CONCLUSIONS

High-quality diagnostic imaging modalities lay the groundwork for a precise definition of an oligometastatic state. By enabling treatment of the entire tumor burden, a delay of systemic therapy, longer progression-free survival, or even curative treatment may become achievable.

Comparison between 18 F-DCFPyL PET and MRI for the detection of transition zone prostate cancer

BACKGROUND

We aimed to compare the diagnostic performance of ¹⁸ F-DCFPyL positron emission tomography (PET) and multiparameter magnetic resonance imaging (mp-MRI) in detecting transition zone (TZ) prostate cancer (PCa).

METHODS

This retrospective study included 20 patients who underwent ¹⁸ F-DCFPyL PET/MRI and 32 patients who underwent ¹⁸ F-DCFPyL PET/CT and MRI from January 2019 to June 2020. All patients had TZ lesions and underwent prostate biopsies. One senior (reader 1) and one junior (reader 2) nuclear medicine physician evaluated each TZ lesion independently, according to the molecular imaging prostate-specific membrane antigen scoring system and the Prostate Imaging Reporting and Data System version 2.1 (PI-RADS v2.1). The histologic diagnosis of prostate biopsy was used as the reference standard. The diagnostic performance of the two methods was compared in terms of inter-reader agreement and area under the receiver operating characteristic (AUC-ROC) curve.

RESULTS

Of the 52 patients, 43 had TZ PCa. For inter-reader agreement, the kappa value was 0.883 for ¹⁸ F-DCFPyL PET and 0.393 for mp-MRI. For PET, both readers had the same diagnostic sensitivity, specificity, and accuracy of 93.0%, 77.8%, and 90.4%, respectively. For mp-MRI, the diagnostic sensitivity, specificity, and accuracy was 67.4%, 33.3%, and 61.5% for reader 1, and 51.2%, 44.4%, and 51.9% for reader 2, respectively. PET outperformed mp-MRI for both readers with an AUC of 0.872 for PET versus 0.584 for mp-MRI, p = .0209 for reader 1, and an AUC of 0.860 for PET versus 0.505 for mp-MRI, p = .0213 for reader 2. Among the 43 patients with TZ PCa, ¹⁸ F-DCFPyL PET detected a distant bone metastasis missed by the CT in one case and two small lymph node metastases missed by the CT and MRI in another case.

CONCLUSIONS

These results suggest that ¹⁸ F-DCFPyL PET, which was almost independent of the experience of the readers, was more objective in the evaluation of TZ lesions, and had higher diagnostic value than mp-MRI.

Molecular Imaging in Primary Staging of Prostate Cancer Patients: Current Aspects and Future Trends

Accurate primary staging is the cornerstone in all malignancies. Different morphological imaging modalities are employed in the evaluation of prostate cancer (PCa). Regardless of all developments in imaging, invasive histopathologic evaluation is still the standard method for the detection and staging of the primary PCa. Magnetic resonance imaging (MRI) and computed tomography (CT) play crucial roles; however, functional imaging provides additional valuable information, and it is gaining ever-growing acceptance in the management of PCa. Targeted imaging with different radiotracers has remarkably evolved in the past two decades. [111In]In-capromab pendetide scintigraphy was a new approach in the management of PCa. Afterwards, positron emission tomography (PET) tracers such as [11C/18F]choline and [11C]acetate were developed. Nevertheless, none found a role in the primary staging. By introduction of the highly sensitive small molecule prostate-specific membrane antigen (PSMA) PET/CT, as well as recent developments in MRI and hybrid PET/MRI systems, non-invasive staging of PCa is being contemplated. Several studies investigated the role of these sophisticated modalities in the primary staging of PCa, showing promising results. Here, we recapitulate the role of targeted functional imaging. We briefly mention the most popular radiotracers, their diagnostic accuracy in the primary staging of PCa, and impact on patient management.

Comparison of 68Ga-Prostate Specific Membrane Antigen (PSMA) Positron Emission Tomography Computed Tomography (PET-CT) and Whole-Body Magnetic Resonance Imaging (WB-MRI) with Diffusion Sequences (DWI) in the Staging of Advanced Prostate Cancer

Simple Summary

Precise staging is key for the optimal management of advanced prostate cancer. PSMA PET-CT and WB-MRI outperform standard imaging technology for staging high-risk prostate cancer, but direct comparison between both modalities is lacking. The primary endpoint of our study was to compare the diagnostic accuracy of both techniques in the detection of lymph node, bone and visceral metastases against a best valuable comparator (BVC), defined as a consensus adjudication of all lesions on the basis of baseline and follow-up imaging, biological and clinical data and histopathologic confirmation when available. Knowing the diagnostic accuracy of both next generation imaging modalities might influence the diagnostic and therapeutic strategy in prostate cancer by tailoring therapy. However, the impact on treatment and patient outcome of an improved detection of metastases has not been determined yet.

Abstract

Background: Prostate specific membrane antigen (PSMA) positron emission tomography computed tomography (PET-CT) and whole-body magnetic resonance imaging (WB-MRI) outperform standard imaging technology for the detection of metastasis in prostate cancer (PCa). There are few direct comparisons between both modalities. This paper compares the diagnostic accuracy of PSMA PET-CT and WB-MRI for the detection of metastasis in PCa. One hundred thirty-four patients with newly diagnosed PCa (n = 81) or biochemical recurrence after curative treatment (n = 53) with high-risk features prospectively underwent PSMA PET-CT and WB-MRI. The diagnostic accuracy of both techniques for lymph node, skeletal and visceral metastases was compared against a best valuable comparator (BVC). Overall, no significant difference was detected between PSMA PET-CT and WB-MRI to identify metastatic patients when considering lymph nodes, skeletal and visceral metastases together (AUC = 0.96 (0.92–0.99) vs. 0.90 (0.85–0.95); p = 0.09). PSMA PET-CT, however, outperformed WB-MRI in the subgroup of patients with newly diagnosed PCa for the detection of lymph node metastases (AUC = 0.96 (0.92–0.99) vs. 0.86 (0.79–0.92); p = 0.0096). In conclusion, PSMA PET-CT outperforms WB-MRI for the detection of nodal metastases in primary staging of PCa.

The Heterogeneous Metabolic Patterns of Ganglia in 68Ga-PSMA, 11C-choline, and 18F-FDG PET/CT in Prostate Cancer Patients

PURPOSE

Studies have indicated that PSMA-positive ganglia represent a diagnostic pitfall for nuclear medicine physicians. No studies have described choline and FDG uptake in ganglia, which may be a source of misdiagnosis. Herein, we described the percentage and uptake pattern of 68Ga-PSMA, 11C-choline and 18F-FDG PET/CT in ganglia and evaluated the heterogeneous metabolic patterns of ganglia to differentiate from lymph node metastases (LNM).

METHODS

Thirty-nine patients who underwent 11C-choline PET/CT and 120 patients who underwent 68Ga-PSMA PET/CT and 18F-FDG PET/CT were retrospectively analyzed. The prevalence of PSMA-positive, choline-positive and FDG-positive ganglia was determined, the SUVmax of ganglia in different locations were measured, and the configuration was described. The SUVmax cutoff of PSMA-PET, choline-PET and FDG-PET was determined by ROC curve analysis to differentiate ganglia from LNM.

RESULTS

329 PSMA-positive ganglia were identified in 120 patients, 95 choline-positive ganglia were identified in 39 patients, and 39 FDG-positive ganglia were identified in 34 patients. PSMA-positive uptake was observed in 98.3%, 95.8%, and 80.0% of cervical, coeliac, and sacral ganglia, respectively. Choline-positive uptake was observed in 84.6%, 97.4%, and 61.5% of cervical, coeliac, and sacral ganglia, respectively. FDG-positive uptake was observed in 16.7%, 13.3%, and 2.5% of cervical, coeliac, and sacral ganglia, respectively. Cervical and coeliac ganglia had a higher rate of PSMA-positive uptake than sacral ganglia. Choline uptake was highest in coeliac ganglia followed by cervical and sacral ganglia. PSMA, choline or FDG uptake in LNM was all significantly higher than ganglia. ROC curve analysis revealed that at a 4.1 SUVmax cutoff of PSMA-PET, the sensitivity, specificity and accuracy of LNM identification was 88.4%, 97.9% and 96.2%, respectively. ROC curve analysis revealed that at a 2.35 SUVmax cutoff for choline-PET, the sensitivity, specificity, and accuracy of LNM identification was 95.0%, 92.6% and 93.0%, respectively. ROC curve analysis revealed that at a 2.55 SUVmax cutoff for FDG-PET, the sensitivity, specificity, and accuracy of LNM identification was 77.3%, 87.2%, and 81.9%, respectively. PSMA-, Choline- and FDG-positive ganglia are mainly band-shaped; most LNMs exhibited nodular and teardrop-shaped configuration.

CONCLUSION

68Ga-PSMA and 11C-choline uptake in ganglia was common, and FDG-positive ganglia were observed at lower frequency. Using 68Ga-PSMA, 11C-choline and 18F-FDG uptake and anatomic location and configuration, the differentiation of ganglia from adjacent LNM is feasible.