Significance of micrometastases in prostate cancer

Treatment and Staging Intensification Strategies Associated with Radical Prostatectomy for High-Risk Prostate Cancer: Efficacy Evaluation and Exploration of Novel Approaches

The management of high-risk prostate cancer (PCa) presents a significant clinical challenge, often necessitating treatment intensification due to the potential presence of micrometastases. While radical prostatectomy (RP) constitutes one of the primary treatment modalities, the integration of neoadjuvant and adjuvant therapies suggests a paradigm shift towards more aggressive treatment strategies, also guided by new imaging modalities like positron emission tomography using prostate-specific membrane antigen (PSMA-PET). Despite the benefits, treatment intensification raises concerns regarding increased side effects. This review synthesizes the latest evidence on perioperative treatment intensification and de-escalation for high-risk localized and locally advanced PCa patients eligible for surgery. Through a non-systematic literature review conducted via PubMed, Scopus, Web of Science, and ClinicalTrials.gov, we explored various dimensions of perioperative treatments, including neoadjuvant systemic therapies, adjuvant therapies, and the role of novel diagnostic technologies. Emerging evidence provides more support for neoadjuvant systemic therapies. Preliminary results from studies suggest the potential for treatments traditionally reserved for metastatic PCa to show apparent benefit in a non-metastatic setting. The role of adjuvant treatments remains debated, particularly the use of androgen deprivation therapy (ADT) and adjuvant radiotherapy in patients at higher risk of biochemical recurrence. The potential role of radio-guided PSMA lymph node dissection emerges as a cutting-edge approach, offering a targeted method for eradicating disease with greater precision. Innovations such as artificial intelligence and machine learning are potential game-changers, offering new avenues for personalized treatment and improved prognostication. The intensification of surgical treatment in high-risk PCa patients is a dynamic and evolving field, underscored by the integration of traditional and novel therapeutic approaches. As evidence continues to emerge, these strategies will refine patient selection, enhance treatment efficacy, and mitigate the risk of progression, although with an attentive consideration of the associated side effects.

Whole Slide Imaging-Based Prediction of TP53 Mutations Identifies an Aggressive Disease Phenotype in Prostate Cancer

In prostate cancer, there is an urgent need for objective prognostic biomarkers that identify the metastatic potential of a tumor at an early stage. While recent analyses indicated TP53 mutations as candidate biomarkers, molecular profiling in a clinical setting is complicated by tumor heterogeneity. Deep learning models that predict the spatial presence of TP53 mutations in whole slide images (WSI) offer the potential to mitigate this issue. To assess the potential of WSIs as proxies for spatially resolved profiling and as biomarkers for aggressive disease, we developed TiDo, a deep learning model that achieves state-of-the-art performance in predicting TP53 mutations from WSIs of primary prostate tumors. In an independent multifocal cohort, the model showed successful generalization at both the patient and lesion level. Analysis of model predictions revealed that false positive (FP) predictions could at least partially be explained by TP53 deletions, suggesting that some FP carry an alteration that leads to the same histological phenotype as TP53 mutations. Comparative expression and histologic cell type analyses identified a TP53-like cellular phenotype triggered by expression of pathways affecting stromal composition. Together, these findings indicate that WSI-based models might not be able to perfectly predict the spatial presence of individual TP53 mutations but they have the potential to elucidate the prognosis of a tumor by depicting a downstream phenotype associated with aggressive disease biomarkers.

SIGNIFICANCE

Deep learning models predicting TP53 mutations from whole slide images of prostate cancer capture histologic phenotypes associated with stromal composition, lymph node metastasis, and biochemical recurrence, indicating their potential as in silico prognostic biomarkers. See related commentary by Bordeleau, p. 2809.

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

Lymph node (LN) metastases have a significant negative impact on the prognosis of urological malignancies. Unfortunately, current imaging modalities are insufficient when it comes to detecting micrometastases; thus, surgical LN removal is commonly used. However, there is still no established ideal lymph node dissection (LND) template, leading to unnecessary invasive staging and the possibility of missing LN metastases located outside the standard template. To address this issue, the sentinel lymph node (SLN) concept has been proposed. This technique involves identifying and removing the first group of draining LNs, which can accurately stage cancer. While successful in breast cancer and melanoma, the SLN technique in urologic oncology is still considered experimental due to high false-negative rates and lack of data in prostate, bladder, and kidney cancer. Nevertheless, the development of new tracers, imaging modalities, and surgical techniques may improve the potential of the SLN procedures in urological oncology. In this review, we aim to discuss the current knowledge and future contributions of the SLN procedure in the management of urological malignancies.

Novel, alternative splicing signature to detect lymph node metastasis in prostate adenocarcinoma with machine learning

Background

The presence of lymph node metastasis leads to a poor prognosis for prostate cancer (Pca). Recently, many studies have indicated that gene signatures may be able to predict the status of lymph nodes. The purpose of this study is to probe and validate a new tool to predict lymph node metastasis (LNM) based on alternative splicing (AS).

Methods

Gene expression profiles and clinical information of prostate adenocarcinoma cohort were retrieved from The Cancer Genome Atlas (TCGA) database, and the corresponding RNA-seq splicing events profiles were obtained from the TCGA SpliceSeq. Limma package was used to identify the differentially expressed alternative splicing (DEAS) events between LNM and non-LNM groups. Eight machine learning classifiers were built to train with stratified five-fold cross-validation. SHAP values was used to explain the model.

Results

333 differentially expressed alternative splicing (DEAS) events were identified. Using correlation filter and the least absolute shrinkage and selection operator (LASSO) method, a 96 AS signature was identified that had favorable discrimination in the training set and validated in the validation set. The linear discriminant analysis (LDA) was the best classifier after 100 iterations of training. The LDA classifier was able to distinguish between LNM and non-LNM with an area under the receiver operating curve of 0.962 ± 0.026 in the training set (D1 = 351) and 0.953 in the validation set (D2 = 62). The decision curve analysis plot proved the clinical application of the AS-based model.

Conclusion

Machine learning combined with AS data could robustly distinguish between LNM and non-LNM in Pca.

Effect of pelvic lymph node dissection and its extent on oncological outcomes in intermediate-risk prostate cancer patients: A multicenter study of the Turkish Uro-oncology Association

BACKGROUND

Pelvic lymph node dissection (PLND) is the gold standard method for lymph node staging in prostate cancer. We aimed to evaluate the effect of PLND combined with radical prostatectomy (RP) on oncological outcomes in D'Amico intermediate-risk prostate cancer (IRPC) patients.

METHODS

Patients with D'Amico IRPC were included in the study. In the overall cohort and subgroups (biopsy International Society of Urological Pathology [ISUP] grade group 2 and 3), patients were divided into two groups as PLND and no-PLND. More extensive PLND, defined as a number of removed nodes (NRN) ≥ 75th percentile.

RESULTS

After exclusion, a total of 631 patients were included: 351 (55.6%) had PLND and 280 (44.4%) had no-PLND. The mean age was 63.1 ± 3.60 years. The median NRN was 8.0 (1.0-40.0). The mean follow-up period was 47.7 ± 37.5 months. The lymph node involvement (LNI) rate was 5.7% in the overall cohort, 3.9% in ISUP grade 2, and 10.8% in ISUP grade 3. Patients with PLND were associated with more aggressive clinicopathologic characteristics but no significant difference in biochemical recurrence-free survival (BCRFS) was found between patients with PLND and no-PLND (p = 0.642). In the subgroup analysis for ISUP grades 2 and 3, no significant difference in BCRFS outcomes was found in patients with PLND and No-PLND (p = 0.680 and p = 0.922). Also, PLND extent had no effect on BCRFS (p = 0.569). The multivariable Cox regression model adjusted for preoperative tumor characteristics revealed that prostate specific antigen (PSA) (HR: 1.18, 95% CI: 1.01-1.25; p = 0.048) was an independent predictor of biochemical recurrence (BCR). The optimum cut-off value for PSA, which can predict BCRFS, was assigned to be 7.81 ng/ml, with an AUC of 0.63 (95% CI: 0.571-0.688). The highest sensitivity and specificity were 0.667 and 0.549.

CONCLUSION

Overall and cancer-specific survival analyzes were not evaluated because not enough events were observed. Neither PLND nor its extent improved BCRFS outcomes in IRPC. The LNI rate is low in patients with biopsy ISUP grade 2 and the BCR rate is low in those with PSA < 7.81 ng/dl so PLND can be omitted in these IRPC patients.

In vitro cytotoxicity of Auger electron-emitting [67Ga]Ga-trastuzumab

Introduction

Molecular radiotherapy exploiting short-range Auger electron-emitting radionuclides has potential for targeted cancer treatment and, in particular, is an attractive option for managing micrometastatic disease. Here, an approach using chelator-trastuzumab conjugates to target radioactivity to breast cancer cells was evaluated as a proof-of-concept to assess the suitability of ⁶⁷Ga as a therapeutic radionuclide.

Methods

THP-trastuzumab and DOTA-trastuzumab were synthesised and radiolabelled with Auger electron-emitters ⁶⁷Ga and ¹¹¹In, respectively. Radiopharmaceuticals were tested for HER2-specific binding and internalisation, and their effects on viability (dye exclusion) and clonogenicity of HER2-positive HCC1954 and HER2–negative MDA-MB-231 cell lines was measured. Labelled cell populations were studied by microautoradiography.

Results

Labelling efficiencies for [⁶⁷Ga]Ga-THP-trastuzumab and [¹¹¹In]In-DOTA-trastuzumab were 90% and 98%, respectively, giving specific activities 0.52 ± 0.16 and 0.61 ± 0.11 MBq/μg (78–92 GBq/μmol). At 4 nM total antibody concentration and 200 × 10³ cells/mL, [⁶⁷Ga]Ga-THP-trastuzumab showed higher percentage of cell association (10.7 ± 1.3%) than [¹¹¹In]In-DOTA-trastuzumab (6.2 ± 1.6%; p = 0.01). The proportion of bound activity that was internalised did not differ significantly for the two tracers (62.1 ± 1.4% and 60.8 ± 15.5%, respectively). At 100 nM, percentage cell binding of both radiopharmaceuticals was greatly reduced compared to 4 nM and did not differ significantly between the two (1.2 ± 1.0% [⁶⁷Ga]Ga-THP-trastuzumab and 0.8 ± 0.9% for [¹¹¹In]In-DOTA-trastuzumab). Viability and clonogenicity of HER2-positive cells decreased when each radionuclide was incorporated into cells by conjugation with trastuzumab, but not when the same level of radioactivity was confined to the medium by omitting the antibody conjugation, suggesting that ⁶⁷Ga needs to be cell-bound or internalised for a therapeutic effect. Microautoradiography showed that radioactivity bound to individual cells varied considerably within the population.

Conclusions

[⁶⁷Ga]Ga-THP-trastuzumab reduced cell viability and clonogenicity only when cell-bound, suggesting ⁶⁷Ga holds promise as a therapeutic radionuclide as part of a targeted radiopharmaceutical. The causes and consequences of non-homogeneous uptake among the cell population should be explored.

Laparoscopic sentinel lymph node dissection in prostate cancer patients: the additional value depends on preoperative data

AIM

In intermediate- or high-risk prostate cancer (PC) patients, to avoid extended pelvic lymph node dissection (ePLND), the updated Briganti nomogram is recommended with the cost of missing 1.5 % of patients with lymph node invasion (LNI). Is it possible to reduce the percentage of unexpected LNI patients (nomogram false negative)? We used the isotopic sentinel lymph node (SLN) technique systematically associated with laparoscopic ePLND to assess the potential value of isotopic SLN method to adress this point.

METHODS

Two hundred and two consecutive patients had procedures with isotopic SLN detection associated with laparoscopic ePLND for high or intermediate risk of PC. The area under the curve (AUC) of the receiver operating characteristics (ROC) analysis was used to quantify the accuracy of different models as: the updated Briganti nomogram, the percentage of positive cores, and an equation of the best predictors of LNI. We tested the model cutoffs associated with an optimal negative predictive value (NPV) and the best cutoff associated with avoiding false negative SLN detection, in order to assist the clinician's decision of when to spare ePLND.

RESULTS

LNI was detected in 35 patients (17.2 %). Based on preoperative primary Gleason grade and percentage of positive cores, a bivariate model was built to calculate a combined score reflecting the risk of LNI. For the Briganti nomogram, the 5 % probability cutoff avoided ePLND in 53 % (108/202) of patients, missing three LNI patients (8.6 %), but all were detected by the SLN technique. For our bivariate model, the best cutoff was <10, leaving no patient with LNI due to positive SLN detection (four patients = 11.4 %), and avoiding ePLND in 52 % (105/202) of patients.

CONCLUSION

For patients with a low risk of LNI determined using the updated Briganti nomogram or bivariate model, SLN technique could be used alone for lymph node staging in intermediate- or high-risk PC patients.

Renal donors with prostate cancer, no longer a reason to decline

OBJECTIVE

To fully assess the true risk of prostate cancer transmission in during renal transplantation.

METHODS

A full review of all existing literature relevant to the topic.

RESULTS

There has not been a single documented case of transmission of prostate cancer during renal transplant. Prostate cancer in deceased organ donors has an incidence estimated between 3% and 18.5% and over 100 transplants have been performed using organs from donor with proven prostate cancer without issue.

CONCLUSION

Transmission of prostate cancer through kidney transplantation seems very unlikely. The risks of remaining on the waiting list are outweighed by a transmission risk and the potential benefit makes the case to have clear guidelines about donor prostate malignancy when accepting potential organs.

Update on histopathological evaluation of lymphadenectomy specimens from prostate cancer patients

BACKGROUND

Metastases to lymph nodes (LNs) represent an unfavorable prognostic factor in patients with prostate cancer (PCa). Histological examination represents the gold standard in the evaluation of the lymphadenectomy (LND) specimens for the presence of secondary deposits.

METHODS AND RESULTS

The metastatic detection rate can vary according to the approach adopted in the microscopic analysis of the LNs, which includes frozen-section examination, total inclusion of the tissue with and without whole-mount sections, serial sectioning, and the application of immunohistochemistry. The assessment of the sentinel LN, the search for micrometastases, and the evaluation of atypical LN metastatic sites further contribute to the detection of the metastatic spread.

CONCLUSION

In this review, an update on the histopathological evaluation of LND specimens in patients with PCa is given, and focus is made on their clinical and prognostic significance.

Nodal occult metastases in intermediate- and high-risk prostate cancer patients detected using serial section, immunohistochemistry, and real-time reverse transcriptase polymerase chain reaction: prospective evaluation with matched-pair analysis

BACKGROUND

The purpose of the study was to prospectively evaluate the incidence of nodal OCM assessed using SS, IHC, and RT-PCR in prostate cancer patients compared with the standard pathological evaluation (SPE), and to evaluate short-term oncological outcomes of patients with OCM.

PATIENTS AND METHODS

Fifty-four consecutive patients with intermediate- or high-risk prostate cancer treated with radical prostatectomy and extended pelvic LN dissection comprised the study population (StP). The central sections with the largest diameter of each LN of the StP and a matched-pair population (MpP) with identical characteristics as the StP were used to assess the improved detection rate of OCM. Pathological characteristics and biochemical recurrence-free survival were assessed according to the presence of macroscopic or OCM.

RESULTS

A total of 1064 LNs were processed in the 54 patients of the StP, with 11 (20.4%) patients with evident metastases at SPE and 7 with OCM (13.0% additional patients); the percentage of positive patients improved from 16.6% (18 of 108) of the MpP to 33.3% (18 of 54) of the StP (16% additional patients). The mean diameter of the 10 additional LNs with OCM found at SS only and of the 6 additional LNs found at IHC only was significantly lower than the mean diameter of the 28 metastases found at routine pathologic examination (RPE) (P < .0001). Patients with OCM showed risk of biochemical recurrence similar to patients with no LN metastases (P = .008).

CONCLUSION

SS, IHC, and RT-PCR can detect a not negligible percentage of OCM missed at RPE. Patients with OCM showed short-term oncological outcomes more similar to those with macroscopic metastases. Longer follow-up studies considering cancer-specific survival are needed.

Low-dose aspirin and survival in men with prostate cancer: a study using the UK Clinical Practice Research Datalink

PURPOSE

Aspirin use is associated with reduced risk of, and death from, prostate cancer. Our aim was to determine whether low-dose aspirin use after a prostate cancer diagnosis was associated with reduced prostate cancer-specific mortality.

METHODS

A cohort of newly diagnosed prostate cancer patients (1998-2006) was identified in the UK Clinical Practice Research Datalink (confirmed by cancer registry linkage). A nested case-control analysis was conducted using conditional logistic regression to compare aspirin usage in cases (prostate cancer deaths) with up to three controls (matched by age and year of diagnosis).

RESULTS

Post-diagnostic low-dose aspirin use was identified in 52 % of 1,184 prostate cancer-specific deaths and 39 % of 3,531 matched controls (unadjusted OR 1.51, 95 % CI 1.19, 1.90; p < 0.001). After adjustment for confounders including treatment and comorbidities, this association was attenuated (adjusted OR  1.02 95 % CI 0.78, 1.34; p = 0.86). Adjustment for estrogen therapy accounted for the majority of this attenuation. There was also no evidence of dose-response association after adjustments. Compared with no use, patients with 1-11 prescriptions and 12 or more prescriptions had adjusted ORs of 1.07 (95 % CI 0.78, 1.47; p = 0.66) and 0.97 (95 % CI 0.69, 1.37; p = 0.88), respectively. There was no evidence of a protective association between low-dose aspirin use in the year prior to diagnosis and prostate cancer-specific mortality (adjusted OR 1.04 95 % CI 0.89, 1.22; p = 0.60).

CONCLUSION

We found no evidence of an association between low-dose aspirin use before or after diagnosis and risk of prostate cancer-specific mortality, after potential confounders were accounted for, in UK prostate cancer patients.

Anatomic extent of pelvic lymph node dissection: impact on long-term cancer-specific outcomes in men with positive lymph nodes at time of radical prostatectomy

OBJECTIVE

To evaluate the impact of an extended pelvic lymph node (LN) dissection (EPLND) on the oncologic outcomes of men with LN-positive prostate cancer.

METHODS

Patients were identified who underwent an open radical prostatectomy by one of two surgeons at the Johns Hopkins Hospital between 1992 and 2003. The first surgeon routinely performed a limited pelvic LN dissection (LPLND), whereas the second performed an EPLND. Men with positive LNs from each cohort were compared for differences in oncologic outcomes.

RESULTS

Positive LNs were found in 94 men (2.2%), 21 (22.3%) with an LPLND and 73 (77.7%) with an EPLND. On average, LPLND and EPLND yielded 11.4 and 14.6 nodes, respectively (P = .022). The two groups were similar in terms of the number of positive LNs (1.4 vs 1.8, P = .223) and the proportion of patients with <15% positive nodes (57.1% vs 69.9%, P = .300). At a median follow-up of 10.5 years, patients who underwent an EPLND had superior oncologic outcomes compared with the LPLND group: 5-year biochemical recurrence-free survival of 30.1% vs 7.1% (P = .018), 10-year metastasis-free survival of 62.2% vs 22.2% (P = .035), and 10-year cancer-specific survival of 83.6% vs 52.6% (P = .199). This analysis demonstrated an augmented improvement in biochemical recurrence-free survival in men with <15% positive nodes.

CONCLUSION

In addition to affording valuable staging information, an EPLND may confer a therapeutic benefit to patients found to have positive LNs at the time of radical prostatectomy.

Pelvic lymph node dissection during robot-assisted radical prostatectomy: efficacy, limitations, and complications-a systematic review of the literature

CONTEXT

Pelvic lymph node dissection (PLND) in prostate cancer is the most effective method for detecting lymph node metastases. However, a decline in the rate of PLND during radical prostatectomy (RP) has been noted. This is likely the result of prostate cancer stage migration in the prostate-specific antigen-screening era, and the introduction of minimally invasive approaches such as robot-assisted radical prostatectomy (RARP).

OBJECTIVE

To assess the efficacy, limitations, and complications of PLND during RARP.

EVIDENCE ACQUISITION

A review of the literature was performed using the Medline, Scopus, and Web of Science databases with no restriction of language from January 1990 to December 2012. The literature search used the following terms: prostate cancer, radical prostatectomy, robot-assisted, and lymph node dissection.

EVIDENCE SYNTHESIS

The median value of nodal yield at PLND during RARP ranged from 3 to 24 nodes. As seen in open and laparoscopic RP series, the lymph node positivity rate increased with the extent of dissection during RARP. Overall, PLND-only related complications are rare. The most frequent complication after PLND is symptomatic pelvic lymphocele, with occurrence ranging from 0% to 8% of cases. The rate of PLND-associated grade 3-4 complications ranged from 0% to 5%. PLND is associated with increased operative time. Available data suggest equivalence of PLND between RARP and other surgical approaches in terms of nodal yield, node positivity, and intraoperative and postoperative complications.

CONCLUSIONS

PLND during RARP can be performed effectively and safely. The overall number of nodes removed, the likelihood of node positivity, and the types and rates of complications of PLND are similar to pure laparoscopic and open retropubic procedures.

Periprostatic lymph node metastasis in prostate cancer and its clinical significance

AIMS

To evaluate the potential of periprostatic lymph node (LN) as a staging indicator, particularly with the use of methods for enhanced detection of micrometastasis.

METHODS AND RESULTS

We retrieved cases with periprostatic LN from radical prostatectomy specimens accrued between 1997 and 2007 at our institution. Twenty-one (0.8%) of 2663 radical prostatectomy specimens had periprostatic LNs (total number of LNs = 22). LN size ranged from 0.8 to 4.7 mm. Most of the periprostatic LNs were located close to the posterior base. Seven (32%) of 22 LNs were involved by metastatic prostate cancer (PCa), including five detected on routine haematoxylin and ceosin slides and an additional two detected only by immunohistochemistry. Cases with periprostatic LNs had a significantly higher metastatic rate (29%; six of 21) compared to those with pelvic LNs sampled at radical prostectatomy in our institution (1.9%). When compared to cases with negative periprostatic LNs (n = 15), the tumour characteristics of cases with metastatic periprostatic LNs (n = 6) included higher tumour volume, Gleason score, stage and a greater propensity for prostate-specific antigen (PSA) recurrence.

CONCLUSIONS

Despite their infrequent identification, periprostatic LNs if detected in the radical prostatectomy specimen should be evaluated with greater scrutiny (step sections and/or immunohistochemical studies) to evaluate their prognostic potential.

Lymph node-positive prostate cancer: current issues, emerging technology and impact on clinical outcome

Lymph node metastasis in patients with prostate cancer indicates a poorer prognosis compared with patients without lymph node metastasis; however, some patients with node-positive disease have long-term survival. Many studies have attempted to discern what characteristics of lymph node metastasis are prognostically significant. These characteristics include nodal tumor volume, number of positive lymph nodes, lymph node density, extranodal extension, lymphovascular invasion and tumor dedifferentiation. Favorable characteristics of regional lymph node involvement included a smaller tumor size and smaller tumor volume. However, the current staging system for prostate cancer does not provide different subclassifications for patients with node-positive prostate cancer. In recent years numerous advanced technologies for the detection of lymph node metastasis have been developed, including molecular imaging techniques and the CellSearch Circulating Tumor Cell System. With the increased detection of patients with prostate cancer, emergence of new technology to identify lymph node metastasis and the number of radical prostatectomies being performed on the rise, subclassifying patients with lymph node-positive disease is imperative. Subclassification would provide a better picture of patient prognosis and allow for a better understanding of targeted therapies to treat patients with lymph node metastasis.

Imaging prostate cancer lymph node metastases with a multimodality contrast agent

BACKGROUND

Methods to detect lymph node (LN) metastases in prostate cancer (PCa) are limited. Pelvic LN dissection is commonly performed during prostatectomy, but often followed by morbid complications. More refined methods for detecting LN invasion are needed.

METHODS

We developed a dual-labeled targeting agent having a near-infrared (NIR) fluorophore for intraoperative guidance, and a conventional radiotracer for detection of LN metastasis. Nu/Nu mice were orthotopically implanted with DsRed-expressing human PCa (PC3) cells. Antibody (Ab) specific for epithelial cell adhesion molecule was conjugated to DOTA, IRDye 800CW, and radiolabeled with (64) Cu. Dual-labeled Ab was administered intravenously at 10-12 weeks post-implantation, and positron emission tomography/computed tomography (PET/CT) and fluorescence imaging were performed within 18-24 hr.

RESULTS

Metastasis to lumbar LNs was detected by DsRed fluorescence imaging, as well as pathology, in 75% of mice having pathology-confirmed primary prostate tumors. These metastases were also detected by NIR fluorescence imaging. In some cases, metastases to sciatic, medial, renal, and axillary nodes were also detected. For all LNs examined, no significant differences were found between the percentages of metastases detected by NIR imaging (63%) and µPET/CT (64%) (P = 0.93), or between those detected by DsRed imaging (25%) and pathological examination (19%) (P = 0.12).

CONCLUSION

This study demonstrates that a multimodality contrast agent is useful for early detection of metastatic disease, and has applications for intraoperative PCa treatment. Further agent optimization is necessary to enhance specificity, and provide validation for prostate and other LN metastasizing epithelial cancers.

The extent of pelvic lymph node dissection correlates with the biochemical recurrence rate in patients with intermediate- and high-risk prostate cancer

OBJECTIVE

• To assess the impact of pelvic lymph node dissection (PLND) and of the number of lymph nodes (LNs) retrieved during radical prostatectomy (RP) on biochemical relapse (BCR) in pNX/0/1 patients with prostate cancer according to the clinical risk of lymph node invasion (LNI).

PATIENTS AND METHODS

• We evaluated 872 pT2-4 NX/0/1 consecutive patients submitted to RP between October 1995 and June 2009, with the following inclusion criteria: (i) a follow-up period ≥12 months; (ii) the avoidance of neoadjuvant hormonal therapy or adjuvant hormonal and/or adjuvant radiotherapy; (iii) the availability of complete follow-up data; (iv) no pathological T0 disease; (v) complete data regarding the clinical stage and Gleason score (Gs), the preoperative prostate-specific antigen (PSA) level and the pathological stage. • The patients were stratified as having low risk (cT1a-T2a and cGs ≤6 and PSA level < 10 ng/mL), intermediate risk (cT2b-T2c or cGs = 7 or PSA level = 10-19.9) or high risk of LNI (cT3 or cGs = 8-10 or PSA level ≥ 20). • The 872 patients were divided into two LN groups according to the number of LNs retrieved: group 1 had no LN or one to nine LNs removed; group 2 had 10 or more LNs. • The variables analysed were LN group, age, PSA level, clinical and pathological stage and Gs, surgical margin status, LN status and number of LN metastases; the primary endpoint was the BCR-free survival.

RESULTS

• The mean follow-up was 55.8 months. • Of all the patients, 305 (35%) were pNx and 567 (65.0%) were pN0/1. • Of the 567 patients submitted to PLND, the mean number of LNs obtained was 10.9, and 49 (8.6%) were pN1. • In the 402 patients at low risk of LNI, LN group was not a significant predictor of BCR at univariate analysis, while in the 470 patients at intermediate and high risk of LNI, patients with ≥ 10 LNs removed had a significantly lower BCR-free survival at univariate and multivariate analysis.

CONCLUSION

• In our study population, a more extensive PLND positively affects the BCR-free survival regardless of the nodal status in intermediate- and high-risk prostate cancer.

Tracer-cocktail injections for combined pre- and intraoperative multimodal imaging of lymph nodes in a spontaneous mouse prostate tumor model

To improve surgical guidance toward prostate draining lymph nodes, we investigate the potential of intraoperative fluorescence imaging and combined pre- and intraoperative multimodality imaging approaches. Transgenic adenocarcinoma mouse prostate mice with spontaneous prostate tumors are injected intratumorally with: 1. a cocktail of patent blue (Pb) and indocyanine green (ICG); 2. a cocktail of albumin radiocolloids (99mTc-NanoColl), Pb, and ICG; or 3. a cocktail of radiolabeled albumin (99mTc-Vasculosis), Pb, and ICG. The distribution of these imaging agents over the lymph nodes (LNs) are studied at different time points after injection. We find that at 60-min postinjection, ICG significantly improves the detection of the LNs compared to Pb, 53 versus 7%, respectively. Moreover, a cocktail of ICG and 99mTc-NanoColl improves the fluorescent detection rate to 86%, equalling that of the clinically applied 99mTc-NanoColl. A similar overlap is observed in our initial clinical pilot data. Fluorescent detection of the LNs using a ICG with 99mTc-Vasculosis gives similar results as "free" ICG (58%; 60 min). A 99mTc-NanoColl, Pb, and cocktail ICG enriches the standard 99mTc-NanoColl approach by adding optical detection of the sentinel lymph nodes. Furthermore, this approach improves fluorescent-based guidance and enables both accurate surgical planning and intraoperative detection, based on a single injection.

Locoregional intravascular viral therapy of cancer: precision guidance for Paris's arrow?

Viral therapy of cancer includes strategies such as viral transduction of tumour cells with 'suicide genes', using viral infection to trigger immune-mediated tumour cell death and using oncolytic viruses for their direct anti-tumour action. However, problems still remain in terms of adequate viral delivery to tumours. A role is also emerging for single-organ isolation and perfusion. Having begun with the advent of isolated limb perfusion for extremity malignancy, experimental systems have been developed for the perfusion of other organs, particularly the liver, kidneys and lungs. These are beginning to be adopted into clinical treatment pathways. The combination of these two modalities is potentially significant. Locoregional perfusion increases the exposure of tumour cells to viral agents. In addition, the avoidance of systemic elimination through the immune and reticulo-endothelial systems should provide a mechanism for increased transduction/infection of target cells. The translation of laboratory research to clinical practice would occur within the context of perfusion programmes, which are already established in the clinic. Many of these programmes include the use of vasoactive cytokines such as tumour necrosis factor-alpha, which may have an effect on viral uptake. Evidence of activation of specific anti-tumour immunological responses by intratumoural and other existing methods of viral administration raises the intriguing possibility of a locoregional therapy, with the ability to affect distant sites of disease. In this review, we examined the state of the literature in this area and summarized current findings before indicating likely areas of continuing interest.