Reconsidering the role of pelvic lymph node dissection with radical prostatectomy for prostate cancer in an era of improving radiological staging techniques

Size of lymph-node metastases in prostate cancer patients undergoing radical prostatectomy: implication for imaging and oncologic follow-up of 2705 lymph-node positive patients

BACKGROUND

Despite modern imaging modalities, lymph-node staging before radical prostatectomy (RP) remains challenging in patients with prostate cancer (PCa). The visibility of lymph-node metastases (LNMs) is critically influenced by their size.

OBJECTIVE

This study aims to describe the distribution of maximal tumor diameters (i.e., size) in LNMs of pN1-PCa at RP and its consequences on visibility in preoperative imaging and oncological outcomes.

DESIGN, SETTING, AND PARTICIPANTS

A total of 2705 consecutive patients with pN1-PCa at RP, harboring a cumulative 7510 LNMs, were analyzed. Descriptive and multivariable analyses addressed the risk of micrometastases (MM)-only disease and the visibility of LNMs. Kaplan-Meier curves and Cox analyses were used for biochemical recurrence-free survival (BCRFS) stratified for MM-only disease.

RESULTS

The median LNM size was 4.5mm (interquartile range (IQR): 2.0-9.0 mm). Of 7510 LNMs, 1966 (26%) were MM (≤ 2mm). On preoperative imaging, 526 patients (19%) showed suspicious findings (PSMA-PET/CT: 169/344, 49%). In multivariable analysis, prostate-specific antigen (PSA) (OR 0.98), age (OR 1.01), a Gleason score greater than 7 at biopsy (OR 0.73), percentage of positive cores at biopsy (OR 0.36), and neoadjuvant treatment (OR 0.51) emerged as independent predictors for less MM-only disease (p < 0.05). Patients with MM-only disease compared to those harboring larger LNMs had a longer BCRFS (median 60 versus 29 months, p < 0.0001).

CONCLUSION

Overall, 26% of LNMs were MM (≤ 2mm). Adverse clinical parameters were inversely associated with MM at RP. Consequently, PSMA-PET/CT did not detect a substantial proportion of LNMs. LNM size and count are relevant for prognosis.

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.

The role of cytoreductive radical prostatectomy and lymph node dissection in bone-metastatic prostate cancer: A population-based study

BACKGROUNDS

The role of cytoreductive radical prostatectomy (cRP) for bone-metastatic prostate cancer (bmPCa) remains controversial. We aimed to figure out whether cRP and lymph node dissection (LND) can benefit bmPCa.

METHODS

11,271 PCa patients with bone metastatic burden from 2010 to 2019 were identified using SEER-Medicare. Overall survival (OS) and cancer-specific survival (CSS) rates were visualized using Kaplan-Meier plots. Multivariable Cox regression analyses were constructed to examine the effects of cRP and LND on survival, after stratifying to age, prostate specific antigen (PSA), clinical stages, Gleason score, metastatic burden, radiotherapy, and chemotherapy status.

RESULTS

317 PCa patients underwent cRP and cRP was increasingly performed for bmPCa from 2010 (2.2%) to 2019 (3.0%) (p < 0.05). In multi analyses, cRP was predisposed to a better OS or CSS in patients with age < 75, PSA < 98 ng/mL, bone-only metastatic sites or patients not receiving chemotherapy (all p < 0.05). For the patients undergoing cRP, LND especially extended LND was associated with a better OS or CSS (all p < 0.05).

CONCLUSIONS

cRP might benefit OS or CSS in young patients with low PSA and bone-only metastatic sites not receiving chemotherapy. And a clear OS or CSS benefit of LND especially extended LND was observed in patients undergoing cRP.

The relationship between biochemical recurrence and number of lymph nodes removed during surgery for localized prostate cancer

PURPOSE

To assess whether completeness of pelvic lymph node dissection (PLND) as measured by lymph node yield reduces biochemical recurrence (BCR) in men undergoing radical prostatectomy (RP) for prostate cancer (PCa), stratified according to Briganti nomogram-derived risk (≥5% vs. < 5%) of lymph node invasion (LNI).

METHODS

Retrospective study of 3724 men who underwent RP between January 1995 and January 2015 from our prospectively collected institutional database. All men included had minimum five years follow-up and were not given androgen deprivation therapy or radiotherapy prior to BCR. Primary endpoint was time to BCR as defined by PSA > 0.2ng/ml. Patients were analysed according to Briganti Nomogram derived risk of 'low-risk' (< 5%) vs. 'high-risk' (≥ 5%). Extent of PLND was analysed using number of nodes yielded at dissection as a continuous variable as well as a categorical variable: Group 1 (limited, 1-4 nodes), Group 2 (intermediate, 5-8 nodes) and Group 3(extensive, ≥9 nodes).

RESULTS

Median follow-up in the overall cohort was 79.7 months and 65% of the total cohort underwent PLND. There were 2402 patients with Briganti risk of LNI < 5% and 1322 with a Briganti risk of LNI ≥5%. At multivariate analysis, only PSA (HR1.01, p < 0.001), extracapsular extension at RP (HR 1.86, p < 0.001), positive surgical margin (HR 1.61, p < 0.001) and positive lymph node on pathology (HR 1.52, p = 0.02) were independently associated with BCR. In the high-risk group, increased nodal yield at PLND was associated with reduction in risk of BCR (HR 0.97, 95%CI 0.95-1.00 p = 0.05, Cochran Mantel Haenszel test, p < 0.05: respectively). In the low-risk group increased number of nodes at PLND did not reduce risk of BCR.

CONCLUSIONS

In this study of extent of PLND at RP, higher nodal yield did not reduce risk of BCR in low-risk men (Briganti risk < 5%), however there was a weak benefit in terms of reduced long-term risk of BCR in high-risk men (Briganti risk ≥5%).

Utility of diffusion weighted imaging-based radiomics nomogram to predict pelvic lymph nodes metastasis in prostate cancer

Background

Preoperative pelvic lymph node metastasis (PLNM) prediction can help clinicians determine whether to perform pelvic lymph node dissection (PLND). The purpose of this research is to explore the feasibility of diffusion-weighted imaging (DWI)-based radiomics for preoperative PLNM prediction in PCa patients at the nodal level.

Methods

The preoperative MR images of 1116 pathologically confirmed lymph nodes (LNs) from 84 PCa patients were enrolled. The subjects were divided into a primary cohort (67 patients with 192 positive and 716 negative LNs) and a held-out cohort (17 patients with 43 positive and 165 negative LNs) at a 4:1 ratio. Two preoperative pelvic lymph node metastasis (PLNM) prediction models were constructed based on automatic LN segmentation with quantitative radiological LN features alone (Model 1) and combining radiological and radiomics features (Model 2) via multiple logistic regression. The visual assessments of junior (Model 3) and senior (Model 4) radiologists were compared.

Results

No significant difference was found between the area under the curve (AUCs) of Models 1 and 2 (0.89 vs. 0.90; P = 0.573) in the held-out cohort. Model 2 showed the highest AUC (0.83, 95% CI 0.76, 0.89) for PLNM prediction in the LN subgroup with a short diameter ≤ 10 mm compared with Model 1 (0.78, 95% CI 0.70, 0.84), Model 3 (0.66, 95% CI 0.52, 0.77), and Model 4 (0.74, 95% CI 0.66, 0.88). The nomograms of Models 1 and 2 yielded C-index values of 0.804 and 0.910, respectively, in the held-out cohort. The C-index of the nomogram analysis (0.91) and decision curve analysis (DCA) curves confirmed the clinical usefulness and benefit of Model 2.

Conclusions

A DWI-based radiomics nomogram incorporating the LN radiomics signature with quantitative radiological features is promising for PLNM prediction in PCa patients, particularly for normal-sized LNM.

Therapeutic value of pelvic lymph node dissection in high-grade prostate cancer

Objective:

This study aimed to assess the therapeutic value of pelvic lymph node dissection (PLND) in high-grade margin-negative prostate cancer without and with lymph node metastases.

Methods:

We retrospectively reviewed cases in the Western Australian radical prostatectomy (RP) database between January 1, 2010, and December 31, 2017. We identified men who had RP only (no PLND) and those had RP with PLND. Further, a subset of high-grade (Gleason score (GS) ⩾8) margin-negative cancers were identified. We assessed the therapeutic impact of PLND in this high-risk but potentially curable subset.

Results:

A total of 5648 prostatectomies were performed, and 1209 of these had concurrent PLND, negative surgical margins, and follow-up prostate-specific antigen (PSA) data. Of 558 men with high-grade margin-negative prostate cancer, 395 men had PLND, while 163 did not. There were significantly more patients with T3/T4 disease in the PLND group compared to those without PLND. Preoperative PSA did not differ significantly between the two groups. However, when stage matched, PLND had no impact on the numbers of men who were cured compared to those who failed surgical intervention.

Conclusion:

PLND has value in staging high-grade prostate cancer but has limited impact on producing a durable PSA cure or avoiding adjuvant therapy.

Level of evidence:

Not applicable for this multicenter audit.

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.

Histological comparison between predictive value of preoperative 3-T multiparametric MRI and 68 Ga-PSMA PET/CT scan for pathological outcomes at radical prostatectomy and pelvic lymph node dissection for prostate cancer

OBJECTIVE

To evaluate the ability of preoperative multiparametric magnetic resonance imaging (mpMRI) and a gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography (⁶⁸ Ga-PSMA PET/CT) scan to predict pathological outcomes and also identify a group of men with a <5% risk of histological pelvic lymph node metastasis (LNM) at pelvic lymph node dissection (PLND) performed during a robot-assisted laparoscopic radical prostatectomy (RALP) for prostate cancer. We then aimed to compare these results to known risk calculators for LNM, including the Cancer of the Prostate Risk Assessment (CAPRA) score, Memorial Sloan Kettering Cancer Centre (MSKCC) and Briganti nomograms.

PATIENTS AND METHODS

Between July 2014 and September 2019 only men who had both a preoperative mpMRI and staging ⁶⁸ Ga-PSMA PET/CT at our institution followed by a RALP with PLND referred to a single specialist uropathology laboratory were considered for inclusion. The data were collected retrospectively prior to February 2019 and in a prospective manner thereafter. A model was built to allocate probabilities of the men with a negative ⁶⁸ Ga-PSMA PET/CT scan having a <5% risk of histologically LNM at RALP based on the preoperative radiological staging.

RESULTS

A total of 233 consecutive men met the inclusion criteria of which 58 men (24.9%) had a LNM identified on PLND histology. The median (range) International Society of Urological Pathology (ISUP) Grade was 5 (1-5) and the median (range) prostate-specific antigen level was 7.4 (1.5-72) ng/mL. The median (range) number of resected lymph nodes was 16 (1-53) and the median (range) number of positive nodes identified on histology was 2 (1-22). Seminal vesicle invasion on mpMRI was more common in node-positive men than in the absence of LNM (31% vs 12%). The maximum standardised uptake value of the primary tumour on ⁶⁸ Ga-PSMA PET/CT was higher in men with LNM (median 9.2 vs 7.2, P = 0.02). Suspected LNM were identified in 42/233 (18.0%) men with ⁶⁸ Ga-PSMA PET/CT compared with 22/233 (9.4%) men with mpMRI (P = 0.023). The positive and negative predictive value for ⁶⁸ Ga-PSMA PET/CT was 66.7% and 84.3% respectively, compared to 59.1% and 78.7% for mpMRI. A predictive model showed only two men (4.2%) with a negative preoperative ⁶⁸ Ga-PSMA PET/CT would be positive for a histological LNM if they are ISUP Grade < 5 and Prostate Imaging-Reporting and Data System (PI-RADS) <5; or ISUP Grade 5 with PI-RADS < 4. An inspection of three additional variables: CAPRA score, MSKCC and Briganti nomograms did not improve the predictive probability for this group. However, of the 61 men with ISUP Grade 4-5 malignancy and also a PI-RADS 5 mpMRI, 20 (32.8%) men had a microscopic LNM despite a negative preoperative ⁶⁸ Ga-PSMA PET/CT.

CONCLUSION

Preoperative ⁶⁸ Ga-PSMA/PET CT was more sensitive in identifying histological pelvic LNM than 3-T mpMRI. Men with a negative ⁶⁸ Ga-PSMA PET/CT have a lower risk of LNM than predicted with CAPRA scores or MSKCC and Briganti nomograms. We identified that the combination of a negative preoperative ⁶⁸ Ga-PSMA PET/CT, ISUP biopsy Grade <5 and PI-RADS <5 prostate mpMRI, or an ISUP Grade 5 with PI-RADS <4 on mpMRI was associated with a <5% risk of a LNM. The addition of CAPRA scores, MSKCC and Briganti nomograms did not improve the predictive probability within this model. Conversely, men with ISUP Grade 4-5 malignancy associated with a PI-RADS 5 prostate mpMRI had a >30% risk of microscopic LNM despite a negative preoperative ⁶⁸ Ga-PSMA PET/CT and this high-risk group would appear suitable for an extended PLND at the time of a radical prostatectomy.

Considering the role of radical prostatectomy in 21st century prostate cancer care

The practice of radical prostatectomy for treating prostate cancer has evolved remarkably since its general introduction around 1900. Initially described using a perineal approach, the procedure was later popularized using a retropubic one, after it was first described as such in 1948. The open surgical method has now largely been abandoned in favour of the minimally invasive robot-assisted method, which was first described in 2000. Until 1980, the procedure was hazardous, often accompanied by massive blood loss and poor outcomes. For patients in whom surgery is indicated, prostatectomy is increasingly being used as the first step in a multitherapeutic approach in advanced local, and even early metastatic, disease. However, contemporary molecular insights have enabled many men to safely avoid surgical intervention when the disease is phenotypically indolent and use of active surveillance programmes continues to expand worldwide. In 2020, surgery is not recommended in those men with low-grade, low-volume Gleason 6 prostate cancer; previously these men - a large cohort of ~40% of men with newly diagnosed prostate cancer - were offered surgery in large numbers, with little clinical benefit and considerable adverse effects. Radical prostatectomy is appropriate for men with intermediate-risk and high-risk disease (Gleason score 7-9 or Grade Groups 2-5) in whom radical prostatectomy prevents further metastatic seeding of potentially lethal clones of prostate cancer cells. Small series have suggested that it might be appropriate to offer radical prostatectomy to men presenting with small metastatic burden (nodal and or bone) as part of a multimodal therapeutic approach. Furthermore, surgical treatment of prostate cancer has been reported in cohorts of octogenarian men in good health with minimal comorbidities, when 20 years ago such men were rarely treated surgically even when diagnosed with localized high-risk disease. As medical therapies for prostate cancer continue to increase, the use of surgery might seem to be less relevant; however, the changing demographics of prostate cancer means that radical prostatectomy remains an important and useful option in many men, with a changing indication.

Undetectable PSA after radical prostatectomy is more likely in low burden N+ prostate cancer patients when an extended lymph node dissection is performed

OBJECTIVES

To analyze the likelihood of undetectable PSA (< 0.01 ng/mL) after extended (ePLND) versus standard pelvic lymph-nodes dissection (sPLND) in pN+ patients.

MATERIALS AND METHODS

The institutional prospectively maintained Prostate Cancer Database was queried for patients who underwent radical prostatectomy with PLND and were found with 3or less lymph-nodal metastases between 2007 and 2017. The extension of the PLND was defined according to the number of lymph-nodes (LN) removed. Patients in the 75th or higher percentile of lymph-nodes removed were considered as the ePLND group; patients in the 25th or lower percentile in the sPLND group. Groups were compared in clinical and pathological variables. Student T-test was used for comparing continuous variables; chi-square test was used for categorical variables. Multivariable logistic regression assessed the probability of undetectable PSA at 3^rd month postoperatively. Kaplan-Meier method estimated the probability of biochemical recurrence. Differences between the groups were compared by Log-rank test.

RESULTS

1478 patients were treated within the time span considered. 95 with 1 to 3 lymph-nodal metastases were extracted. After accounting for inclusion criteria, 23 patients with a median of 11 LN removed were included in the sPLND group (25th percentile); 23 patients with > 27 LN were included in ePLND group (75th percentile). Surgical time was longer for ePLND. Sixteen patients (69.6%) who underwent ePLND had undetectable PSA postoperatively. At multivariable analysis, the probability of undetectable PSA at 3^rd month was higher in patients who received an ePLND (HR=5.18; IC 95%=1.16-23.11; P=.03).

CONCLUSIONS

ePLND is more likely to predict undetectable PSA at third month after radical prostatectomy, irrespective of disease characteristics.

68Ga-PSMA PET/CT-based metastasis-directed radiotherapy for oligometastatic prostate cancer recurrence after radical prostatectomy. World J Urol. 2019;37:1535-1542. [PMID: 30824985 DOI: 10.1007/s00345-019-02701-1]

PURPOSE

The aim of this communication was to assess the efficacy of directed oligometastatic radiotherapy (RT) based on ⁶⁸Ga-PSMA PET/CT in patients with prostate cancer (PCa) biochemical relapse (BCR) after primary treatment with curative intent.

METHODS

This is a retrospective analysis of a monocentric cohort of PCa patients diagnosed with oligometastatic disease on ⁶⁸Ga-PSMA PET/CT and treated with metastasis-directed RT. Inclusion criteria were: histologically proven PCa, BCR after primary treatment with curative intent, oligometastatic disease defined as ≤ 3 metastatic lesions. To evaluate the efficacy of the therapy, biochemical response defined as a decrease of > 50% of PSA (PSA₅₀) was measured at 1 and 4 months. Patients were followed up until progression and start of androgen deprivation therapy (ADT). BCR-free survival and ADT-free survival were calculated.

RESULTS

20 patients met the inclusion criteria. Median PSA value: 1.4 ng/ml (IQR, 0.3-2.3 ng/ml). A total of 30 PSMA-positive lesions were treated: 18 lymph nodes (60%), nine bone (30%) and three visceral lesions (10%). Median follow-up was 15 months (range 4-33 months). Biochemical response at 1 and 4 months was found in 3/20 patients (15%) and 14/20 (70%), respectively. BCR-free survival rate at 1 year was 79% and 53% at 2 years. ADT-free survival at 2 years was 74%.

CONCLUSION

This retrospective study suggests that metastasis-directed RT based on ⁶⁸Ga-PSMA PET/CT may be a valuable treatment in patients with PCa oligometastatic disease, providing promising BCR-free survival rates and potentially postponing ADT for at least 2 years in 74% of the patients. Response assessment should not be measured before 4 months after treatment.

Consensus statements on the management of clinically localized prostate cancer from the Hong Kong Urological Association and the Hong Kong Society of Uro-Oncology

OBJECTIVE

To formulate consensus statements to facilitate physician management strategies for patients with clinically localized prostate cancer (PCa) in Hong Kong by jointly convening a panel of 12 experts from the two local professional organizations representing PCa specialists, who had previously established consensus statements on the management of metastatic PCa for the locality.

METHODS

Through a series of meetings, the panellists discussed their clinical experience and the published evidence regarding various areas of the management of localized PCa, then drafted consensus statements. At the final meeting, each drafted statement was voted on by every panellist based on its practicability of recommendation in the locality.

RESULTS

A total of 76 consensus statements were ultimately accepted and established by panel voting.

CONCLUSION

Derived from the recent evidence and major overseas guidelines, along with local clinical experience and practicability, the consensus statements were aimed to serve as a practical reference for physicians in Hong Kong for the management of localized PCa.

Oncological Outcomes of Open Radical Retropubic Prostatectomy in Ireland: A Single Surgeon's 5-Year Experience

Objectives  There is a little published data on the outcomes of radical prostatectomy in the Irish context. We aimed to determine the 5-year oncological results of open radical retropubic prostatectomy (RRP) performed by a single surgeon following appointment. Methods  A retrospective review of RRPs performed between 2011 and 2016 was conducted. Patient demographics, preoperative parameters (clinical stage on digital rectal exam, prostate-specific antigen (PSA) levels, biopsy Gleason's score and MRI [magnetic resonance imaging] findings), pathological variables (T-stage, Gleason's score, nodal status, and surgical margin status), and treatment decisions (lymphadenectomy or adjuvant radiotherapy) were recorded. Oncological outcome at last follow-up was ascertained. Results  265 patients underwent RRP between 2011 and 2016. Median age was 62 years (range: 41-74). Mean follow-up was 32.24 months (range: 8-72) months. Pathological disease stage was T2 in 170/265 (64.15%), T3a in 65/265 (24.53%), and T3b in 30/265 (11.32%). Final Gleason's score was upgraded from diagnostic biopsy in 16.35% (43/263) and downgraded in 27% (71/263). Pelvic lymph node dissection was performed in 44.25% (118/265) patients. A positive surgical margin (PSM) was seen in 26/170 (15.2%) patients with T2 disease and in 45/95 (47.37%) patients with T3 disease. Of the 265 patients, 238 (89.81%) were disease-free at last follow-up, of whom 24/238 (10.08%) had received adjuvant and 17/238 (7.14%) received salvage radiotherapy. Adjuvant/salvage treatment was ongoing in 19/265 (7.17%) of patients. Conclusion  Good oncological outcomes of RRP in the Irish context are seen in this 5-year review, with the vast majority of patients experiencing biochemical-free survival at most recent follow-up.

PSMA-PET guided hook-wire localization of nodal metastases in prostate cancer: a targeted approach

Prostate Specific Membrane Antigen Positron Emission Tomography/Computed Tomography (PSMA-PET/CT) has increased the sensitivity and specificity of imaging to identify metastatic prostate cancer in the group of patients with early biochemical recurrence when compared to conventional imaging. In patients who develop biochemical recurrence of prostate cancer following surgical resection, salvage lymph node dissection may reduce prostate specific antigen (PSA) levels and delay the time for commencement of systemic therapies. However, PLND may be an anatomically and technically difficult procedure, particularly with small metastatic diseases which can be problematic for intra-operative identification. We describe the technique using PSMA-PET imaging to pre-operatively localise areas of low-volume nodal metastatic disease with hookwire to allow targeted lymph node dissection with direct visualisation and palpation to ensure adequate clearance of involved nodes.