Pathologic basis of focal therapy for early-stage prostate cancer

MR-guided Focused Ultrasound Focal Therapy for Prostate Cancer

Prostate cancer (PCa) is a prevalent malignancy in men, and the management of localized disease has evolved significantly in recent years. Focal therapy, wherein the biopsy confirmed site of tumor with margins is treated leaving the remaining gland intact, has emerged as a promising strategy for treating localized clinically significant PCa, minimizing side effects associated with radical therapies. We present the technical aspects, a summary of the most relevant evidence to date on the performance and safety of this technique, and the characteristic MR imaging findings during treatment, in the early posttreatment period and in the long term.

Single-center, prospective phase 2 trial of high-intensity focused ultrasound (HIFU) in patients with unilateral localized prostate cancer: good functional results but oncologically not as safe as expected

PURPOSE

Focal therapy (FT) for localized prostate cancer (PCa) is only recommended within the context of clinical trials by international guidelines. We aimed to investigate oncological follow-up and safety data of focal high-intensity focused ultrasound (HIFU) treatment.

METHODS

We conducted a single-center prospective study of 29 patients with PCa treated with (focal) HIFU between 2016 and 2021. Inclusion criteria were unilateral PCa detected by mpMRI-US-fusion prostate biopsy and maximum prostate specific antigen (PSA) of 15 ng/ml. Follow-up included mpMRI-US fusion-re-biopsies 12 and 24 months after HIFU. No re-treatment of HIFU was allowed. The primary endpoint was failure-free survival (FFS), defined as freedom from intervention due to cancer progression.

RESULTS

Median follow-up of all patients was 23 months, median age was 67 years and median preoperative PSA was 6.8 ng/ml. One year after HIFU treatment PCa was still detected in 13/ 29 patients histologically (44.8%). Two years after HIFU another 7/29 patients (24.1%) were diagnosed with PCa. Until now, PCa recurrence was detected in 11/29 patients (37.93%) which represents an FFS rate of 62%.One patient developed local metastatic disease 2 years after focal HIFU. Adverse events (AE) were low with 70% of patients remaining with sufficient erectile function for intercourse and 97% reporting full maintenance of urinary continence.

CONCLUSION

HIFU treatment in carefully selected patients is feasible. However, HIFU was oncologically not as safe as expected because of progression rates of 37.93% and risk of progression towards metastatic disease. Thus, we stopped usage of HIFU in our department.

Photodynamic therapy for prostate cancer: Recent advances, challenges and opportunities

Over the past two decades, there has been a tendency toward early diagnosis of prostate cancer due to raised awareness among the general public and professionals, as well as the promotion of prostate-specific antigen (PSA) screening. As a result, patients with prostate cancer are detected at an earlier stage. Due to the risks of urine incontinence, erectile dysfunction, etc., surgery is not advised because the tumor is so small at this early stage. Doctors typically only advise active surveillance. However, it will bring negative psychological effects on patients, such as anxiety. And there is a higher chance of cancer progression. Focal therapy has received increasing attention as an alternative option between active monitoring and radical therapy. Due to its minimally invasive, oncological safety, low toxicity, minimal effects on functional outcomes and support by level 1 evidence from the only RCT within the focal therapy literature, photodynamic treatment (PDT) holds significant promise as the focal therapy of choice over other modalities for men with localized prostate cancer. However, there are still numerous obstacles that prevent further advancement. The review that follows provides an overview of the preclinical and clinical published research on PDT for prostate cancer from 1999 to the present. It focuses on clinical applications of PDT and innovative techniques and technologies that address current problems, especially the use of nanoparticle photosensitizers in PDT of prostate cancer.

Techniques and Outcomes of Salvage Robot-Assisted Radical Prostatectomy (sRARP)

BACKGROUND

Salvage Robot-Assisted Radical Prostatectomy (sRARP) has been described as feasible treatment for the management of localised prostate cancer (PCa) recurrence after primary treatment. However, no large reports have published cancer and quality outcomes.

OBJECTIVE

To report perioperative, functional and oncologic outcomes of sRARP in patients with localised PCa recurrence.

DESIGN, SETTING, AND PARTICIPANTS

We retrospectively evaluated 106 patients with local recurrence eligible for sRARP.

SURGICAL PROCEDURE

Surgery was performed using the DaVinci Si system similar to the standard approach but with adaptation to the primary treatment.

MEASUREMENTS

Peri-operative outcomes included 90-day complication rate. Functional outcomes included rates of incontinence and erectile dysfunction. Oncological outcomes included tumour staging, margin rate and recurrence.

RESULTS AND LIMITATIONS

Primary treatment was High Intensity Focused Ultrasound (HIFU) in 59 (56%) patients, 27 (25%) radiotherapy, 10 (9%) seed brachytherapy, 8 (8%) solitary androgen deprivation therapy (ADT), one (1%) cryotherapy and one (1%) electroporation / Nanoknife. Median follow-up was 2.1 years. 90-day complication rate was 8%. At two years or more, 50% were fully continent and 33% were socially continent. Continence rates tended to be better after focal compared to whole-gland treatments. Erectile dysfunction was present in 95%. Positive surgical margin rate was 39%. Biochemical recurrence occurred in 13% and local or metastatic recurrence in 11%.

CONCLUSIONS

sRARP is technically more challenging but is a feasible option in high-volume centres for treatment of recurrent PCa. Patients should be counselled that functional outcomes are inferior to primary RARP. Adjustment of surgical technique according to the primary treatment is key for good surgical outcomes.

PATIENT SUMMARY

We report our experience with sRARP for the management of localised PCa recurrence after primary treatment. This represents a feasible approach with acceptable peri-operative complications and cancer outcomes. Functional outcomes are inferior to RARP in the primary setting.

"Super-active surveillance": MRI ultrasound fusion biopsy and ablation for less invasive management of prostate cancer

Multiparametric magnetic resonance imaging (mpMRI) of the prostate has allowed clinicians to better visualize and target suspicious lesions during biopsy. Targeted prostate biopsies give a more accurate representation of the true cancer volume and stage so that appropriate treatment or active surveillance can be selected. Advances in technology have led to the development of MRI and ultrasound fusion platforms used for targeted biopsies, monitoring cancer progression, and more recently for the application of focal therapy. Lesions visualized on mpMRI can be targeted for ablation with a variety of energy sources employed under both local and general anesthesia. Focal ablation may offer an alternative option for treating prostate cancer as compared to the well-established interventions of whole-gland radiation or prostatectomy. Focal ablation may also be an option for patients on active surveillance who wish to be even more "active" in their surveillance. In this review, we describe the advancements and development of fusion biopsies, the rationale behind focal therapy, and introduce focal ablative techniques for indolent prostate cancers ("super-active surveillance"), including cryoablation and focal laser ablation (FLA) and the subsequent MRI/biopsy surveillance.

Low-risk Prostate Cancer: Identification, Management, and Outcomes

CONTEXT

The incidence of low-risk prostate cancer (PCa) has increased as a consequence of prostate-specific antigen testing.

OBJECTIVE

In this collaborative review article, we examine recent literature regarding low-risk PCa and the available prognostic and therapeutic options.

EVIDENCE ACQUISITION

We performed a literature review of the Medline, Embase, and Web of Science databases. The search strategy included the terms: prostate cancer, low risk, active surveillance, focal therapy, radical prostatectomy, watchful waiting, biomarker, magnetic resonance imaging, alone or in combination.

EVIDENCE SYNTHESIS

Prospective randomized trials have failed to show an impact of radical treatments on cancer-specific survival in low-risk PCa patients. Several series have reported the risk of adverse pathologic outcomes at radical prostatectomy. However, it is not clear if these patients are at higher risk of death from PCa. Long-term follow-up indicates the feasibility of active surveillance in low-risk PCa patients, although approximately 30% of men starting active surveillance undergo treatment within 5 yr. Considering focal therapies, robust data investigating its impact on long-term survival outcomes are still required and therefore should be considered experimental. Magnetic resonance imaging and tissue biomarkers may help to predict clinically significant PCa in men initially diagnosed with low-risk disease.

CONCLUSIONS

The incidence of low-risk PCa has increased in recent years. Only a small proportion of men with low-risk PCa progress to clinical symptoms, metastases, or death and prospective trials have not shown a benefit for immediate radical treatments. Tissue biomarkers, magnetic resonance imaging, and ongoing surveillance may help to identify those men with low-risk PCa who harbor more clinically significant disease.

PATIENT SUMMARY

Low-risk prostate cancer is very common. Active surveillance has excellent long-term results, while randomized trials have failed to show a beneficial impact of immediate radical treatments on survival. Biomarkers and magnetic resonance imaging may help to identify which men may benefit from early treatment.

Prostate cancer diagnosis by optical coherence tomography: First results from a needle based optical platform for tissue sampling

The diagnostic accuracy of Optical Coherence Tomography (OCT) based optical attenuation coefficient analysis is assessed for the detection of prostate cancer. Needle-based OCT-measurements were performed on the prostate specimens. Attenuation coefficients were determined by an earlier described in-house developed software package. The mean attenuation coefficients (benign OCT data; malignant OCT data; p-value Mann-Whitney U test) were: (3.56 mm(-1) ; 3.85 mm(-1) ; p < 0.0001) for all patients combined. The area under the ROC curve was 0.64. In order to circumvent the effect of histopathology mismatching, we performed a sub-analysis on only OCT data in which tumor was visible in two subsequent histopathological prostate slices. This analysis could be performed in 3 patients. The mean attenuation coefficients (benign OCT data; malignant OCT data; p-value Mann-Whitney U test) were: (3.23 mm(-1) ; 4.11 mm(-1) ; p < 0.0001) for all patients grouped together. The area under the ROC curve was 0.89. Functional OCT of the prostate has shown to differentiate between cancer and healthy prostate tissue. The optical attenuation coefficient in malignant tissue was significantly higher in malignant tissue compared to benign prostate tissue. Further studies are required to validate these initial results in a larger group of patients with a more tailored histopathology matching protocol.

Pelvic applications of MR-guided high intensity focused ultrasound

MR-guided high intensity focused ultrasound (MRg HIFU) is a novel method of tissue ablation that incorporates high energy focused ultrasound for tissue heating and necrosis within an MR scanner that provides simultaneous stereotactic tissue targeting and thermometry. To date, MRg HIFU has been used primarily to treat uterine fibroids, but many additional applications in the pelvis are in development. This article reviews the basic technology of MRg HIFU, and the use of MRg HIFU to treat uterine fibroids, adenomyosis, and prostate cancer.

Endorectal MRI and MR spectroscopic imaging of prostate cancer: developing selection criteria for MR-guided focal therapy

PURPOSE

To investigate criteria that can identify dominant treatable prostate cancer foci with high certainty at endorectal magnetic resonance imaging (MRI) and MR spectroscopic (MRS) imaging, and thus facilitate selection of patients who are radiological candidates for MR-guided focal therapy.

MATERIALS AND METHODS

We retrospectively identified 88 patients with biopsy-proven prostate cancer who underwent endorectal MRI and MRS imaging prior to radical prostatectomy with creation of histopathological tumor maps. Two independent readers noted the largest tumor foci at MRI, if visible, and the volume of concordant abnormal tissue at MRS imaging, if present. A logistic random intercept model was used to determine the association between clinical and MR findings and correct identification of treatable (over 0.5 cm3) dominant intraprostatic tumor foci.

RESULTS

Readers 1 and 2 identified dominant tumor foci in 50 (57%) and 58 (65%) of 88 patients; 42 (84%) and 48 (83%) of these were dominant treatable lesions at histopathology, respectively. Within the statistical model, the volume of concordant spectroscopic abnormality was the only factor that predicted correct identification of a dominant treatable lesion on T2-weighted images (odds ratio=1.75; 95% confidence interval=1.08 to 2.82; P value=0.02). In particular, all visible lesions on T2-weighted imaging associated with at least 0.54 cm3 of concordant spectroscopic abnormality were correctly identified dominant treatable tumor foci.

CONCLUSION

Patients with dominant intraprostatic tumor foci seen on T2-weighted MRI and associated with at least 0.54 cm3 of concordant MRS imaging abnormality may be radiological candidates for MR-guided focal therapy.

Focal brachytherapy for selected low-risk prostate cancers: a pilot study

PURPOSE

To evaluate the feasibility and the early toxicity of focal brachytherapy in highly selected localized prostate cancer patients.

METHODS AND MATERIALS

Twenty-one patients underwent a focal brachytherapy between February 2010 and March 2012, representing 3.7% of the cases treated by our group during this period. Patient selection was based on (at least) two series of prostate biopsies and a high-resolution MRI. Only patients with very limited and localized tumors, according to strict criteria, were selected for the procedure. The technique used a real-time procedure with the implantation of free (125)I seeds and dynamic dose calculation. The prescribed dose for the focal volume was 145Gy.

RESULTS

The treated volume corresponded to a mean value of 34% of the total prostatic volume (range, 20-48%). For the focal volume, the mean D90 and V100 was 183.2Gy (range, 176-188Gy) and 99.3% (range, 98.8-100%), respectively. The technique was performed in an hour and a half. When compared with a previous cohort treated by whole-prostate brachytherapy, urinary toxicity (International Prostate Symptom Score) was borderline reduced (p = 0.04) at 6 months only, whereas the recovery of the International Index of Erectile Function 5 was better (p = 0.014). The International Continence Score was nil in almost all cases as well as rectal toxicity.

CONCLUSION

Focal treatment by brachytherapy is easily feasible with little acute toxicity. Further investigation is needed to assess the results in terms of tumor control and long-term toxicity.

Exposure to leachate from municipal battery recycling site: implication as key inhibitor of steroidogenic enzymes and risk factor of prostate damage in rats

Few or no studies have measured the effect of short- and long-term exposure to industrial leachate. Mature male Wistar strain albino rats (175-220 g) underwent sub-chronic exposure to leachate from the Elewi Odo municipal battery recycling site (EOMABRL) via oral administration for a period of 60 days at different doses (20%, 40%, 60%, 80%, and 100%) per kilogram of body weight to evaluate the toxic effects of the leachate on male reproductive function using steroidogenic enzymes and biomarkers of prostate damage. Control groups were treated equally but were given distilled water instead of the leachate. After the treatment periods, results showed that the treatment induced systemic toxicity at the doses tested by causing a significant (p<0.05) loss in absolute body weight and decline in growth rate. There was a marked significant decrease (p<0.05) in testicular activities of Δ(5)-3β-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase. Conversely, the activity of prostatic acid phosphatase, a key marker enzyme for prostrate damage was significantly (p<0.05) elevated in the treated rats. Similarly, the administration of EOMABRL significantly (p<0.05) exacerbated the activity of total acid phosphatase with concomitant increase in the activity of prostatic alkaline phosphatase. These findings conclude that exposure to leachate from a battery recycling site induces sub-chronic testicular toxicity by inhibiting key steroidogenic enzymes and activating key markers linked with prostate damage/cancer in rats.

Focal therapy for prostate cancer: patient selection and evaluation

Recent stage migration toward low-risk prostate cancer, overtreatment of biologically insignificant tumors with radical prostatectomy at the additional expense of a non-negligible morbidity and undertreatment of patients improperly selected for active surveillance are the main reasons that have fueled the concept of focal therapy. Optimal selection of patients is the key for the successful implementation of focal therapy. Selection criteria for focal therapy vary widely and depend on clinical, histological and imaging characteristics of the patients that are highlighted in this article. In addition, the rationales, merits and limitations of the available methods for the assessment of potential candidates, the evaluation of treatment efficacy and follow-up of these patients are discussed.

Focal laser ablation of prostate cancer: numerical simulation of temperature and damage distribution

Background

The use of minimally invasive ablative techniques in the management of patients with low grade and localized prostate tumours could represent a treatment option between active surveillance and radical therapy. Focal laser ablation (FLA) could be one of these treatment modalities. Dosimetry planning and conformation of the treated area to the tumor remain major issues, especially when, several fibers are required. An effective method to perform pre-treatment planning of this therapy is computer simulation. In this study we present an in vivo validation of a mathematical model.

Methods

The simulation model is based on finite elements method (FEM) to solve the bio-heat and the thermal damage equations. Laser irradiation was performed with a 980 nm laser diode system (5 W, 75 s). Light was transmitted using a cylindrical diffusing fiber inserted inside a preclinical animal prostate cancer model induced in Copenhagen rats. Non-enhanced T2-weighted and dynamic gadolinium-enhanced T1-weighted MR imaging examinations were performed at baseline and 48 hours after the procedure. The model was validated by comparing the simulated necrosis volume to the results obtained in vivo on (MRI) and by histological analysis. 3 iso-damage temperatures were considered 43° C, 45° C and 50° C.

Results

The mean volume of the tissue necrosis, estimated from the histological analyses was 0.974 ± 0.059 cc and 0.98 ± 0.052 cc on the 48 h MR images. For the simulation model, volumes were: 1.38 cc when T = 43° C, 1.1 cc for T = 45°C and 0.99 cc when T = 50 C°.

Conclusions

In this study, a clear correlation was established between simulation and in vivo experiments of FLA for prostate cancer.

Simulation is a promising planning technique for this therapy. It needs further more evaluation to allow to FLA to become a widely applied surgical method.

Are we able to correctly identify prostate cancer patients who could be adequately treated by focal therapy?

INTRODUCTION AND OBJECTIVE

Because of the improvements on detection of early stage prostate cancer over the last decade, focal therapy for localized prostate cancer (PC) has been proposed for patients with low-risk disease. Such treatment would allow the control of cancer, thereby diminishing side effects, such as urinary incontinence and sexual dysfunction, which have an enormous impact on quality of life. The critical issue is whether it is possible to preoperatively predict clinically significant unifocal or unilateral prostate cancer with sufficient accuracy. Our aim is to determine whether there is any preoperative feature that can help select the ideal patient for focal therapy.

MATERIAL AND METHODS

A total of 599 patients who underwent transrectal ultrasound (TRUS)-guided prostate biopsy followed by radical prostatectomy to treat PC were examined in our laboratory between 2001 and 2009. We established very restricted criteria to select patients with very-low-risk disease for whom focal therapy would be suitable (only 1 biopsy core positive, tumor no larger than 80% of a single core, no perineural invasion, PSA serum level < 10 ng/ml, Gleason score < 7 and clinical stage T1c, T2a-b). We defined 2 groups of patients who would be either adequately treated or not treated by focal therapy. The primary endpoint was the evaluation of preoperative features in order to identify which parameters should be considered when choosing good candidates for focal therapy.

RESULTS

Fifty-six out of 599 patients met our criteria. The mean age was 59 years, and the mean number of biopsy cores was 14.4. Forty-seven (83.9%) were staged T1c, and 9 (16.1%) were staged T2a-b. Forty-four (78.6%) patients could be considered to have been adequately treated by focal therapy, and 12 (21.4%) could not. There was no statistical difference between the 2 groups considering age, clinical stage, PSA levels, Gleason score, and tumor volume in the biopsy. All 12 patients who could be considered inadequately treated had a bilateral, significant secondary tumor, 58.3% had Gleason ≥ 7, and 25% were staged pT3.

CONCLUSION

Although focal therapy might be a good option for patients with localized prostate cancer, we are so far unable to select which of them would benefit from it based on preoperative data, even using very restricted criteria, and a considerable proportion of men would still be left undertreated.

The index lesion and focal therapy: an analysis of the pathological characteristics of prostate cancer

OBJECTIVE

To determine the pathological characteristics of radical prostatectomy specimens with respect to index and secondary lesions.

METHODS

A total of 100 consecutive radical prostatectomy specimens examined at a single hospital were assessed. Patients undergoing salvage prostatectomy or those who had received neoadjuvant hormonal manipulation were excluded. Preoperative data and the number, volume and Gleason grade of each tumour focus were recorded. Criteria used to define a clinically significant lesion were tumour volume ≥0.5 mL and/or Gleason pattern 4 or 5 and/or extra-capsular disease.

RESULTS

Overall, 374 foci were examined. The median number of tumours per patient was 3.5 (range 1-15). The overall median tumour volume was 1.4 mL (range 0.1-18.2), the median volume of the largest (index) tumour was 0.95 mL (range 0.1-18.2) and the median volume of the largest secondary tumour was 0.2 mL (range 0.05-1.7). There were no patients in whom the index lesion was insignificant and secondary tumours were significant (by grade or extra-capsular disease). Seventy-seven fulfilled the clinical parameters of low-to-intermediate-risk disease. If focal therapy can be delivered with the aim of ablating all clinically significant disease, with untreated areas harbouring no cancer or clinically insignificant disease, between 58.5 and 67.5% might have been suitable for such a strategy.

CONCLUSIONS

The proportion of men with low-to-intermediate-risk prostate cancer who may potentially be suitable for a focal therapy approach is unknown. The key question is whether the volume of individual lesions points to clinically significant cancer and whether ablation of these lesions alone would lead to cancer control. This research question is currently undergoing evaluation within a prospective clinical trial.

Serum prostate-specific antigen value adjusted for non-cancerous prostate tissue volume in patients undergoing radical prostatectomy: a new predictor of biochemical recurrence in localized or locally advanced prostate cancer

The aim of this study was to investigate the significance of serum prostate-specific antigen (PSA) value adjusted for total tumor volume (PSA/tumor volume) and serum PSA value adjusted for non-cancerous prostate tissue volume (NCPV) (PSA/NCPV) as a predictor of pathological findings and clinical outcome after radical prostatectomy. Clinical and pathological data of 407 patients (median age: 66.5 years; range: 41.8-85.7 years) were reviewed retrospectively. The median follow-up period was 18.1 months (range: 1.0-107.8 months). Biochemical recurrence was defined as detectable PSA levels (greater than 0.2 ng ml(-1)) and the time of biochemical recurrence was taken to be the first time PSA became detectable. In the multivariate model, PSA/NCPV was an independent predictor of extracapsular extension and positive surgical margin (P<0.05), but PSA/tumor volume was not. Kaplan-Meier curves revealed that PSA/NCPV correlated with biochemical recurrence-free survival (P<0.001; log-rank test) but PSA/tumor volume did not (P=0.275; log-rank test). PSA/NCPV was also a significant independent prognostic factor for biochemical recurrence-free survival on multivariate Cox proportional hazard analysis (P=0.004, relative risk=2.42). Our findings suggest that PSA/NCPV is associated independently with extracapsular extension and surgical margin status and may be an independent prognostic variable of PSA recurrence after radical prostatectomy.

Impact of prostate cancer multifocality on its biology and treatment

Any focal therapy requires correct localization of the lesion; consequently, much effort is now devoted to accurate characterization of the spatial distribution of the tumor within the prostate. One of the greatest difficulties in the localization of prostate cancer is its frequent multifocality, but prostate cancer is unifocal in 13% to 43.7% of cases and unilateral in 19.2%. In cases of multifocality, it seems that the index tumor is the biologic driving force behind the malignant potential of prostate cancer. Not only is the Gleason score of the secondary nodes lower than that of the index node, but 80% of the secondary nodes are smaller than 0.5 cc and almost all extraprostatic extensions are associated with the largest cancers. While current evaluation with 12 to 18 core biopsies may be adequate to determine the index lesion, transperineal three-dimensional mapping biopsy of the prostate should be undertaken if greater accuracy is needed.

Focal therapy in prostate cancer-report from a consensus panel

PURPOSE

To establish a consensus in relation to case selection, conduct of therapy, and outcomes that are associated with focal therapy for men with localized prostate cancer.

MATERIAL AND METHODS

Urologic surgeons, radiation oncologists, radiologists, and histopathologists from North America and Europe participated in a consensus workshop on focal therapy for prostate cancer. The consensus process was face to face within a structured meeting, in which pertinent clinical issues were raised, discussed, and agreement sought. Where no agreement was possible, this was acknowledged, and the nature of the disagreement noted.

RESULTS

Candidates for focal treatment should have unilateral low- to intermediate-risk disease with clinical stage <or=cT(2a). Prostate size and both tumor volume and tumor topography are important case selection criteria that depend on the ablative technology used. Currently, the best method to ascertain the key characteristics for men who are considering focal therapy is exposure to transperineal template mapping biopsies. MRI of the prostate using novel techniques such as dynamic contrast enhancement and diffusion weighed imaging are increasingly being used to diagnose and stage primary prostate cancer with excellent results. For general use, however, these new techniques require validation in prospective clinical trials. Until such are performed, MRI will, in most centers, continue to be an investigative tool in assessing eligibility of patients for focal therapy.

CONCLUSIONS

Consensus was derived for most of the key aspects of case selection, conduct of treatment, and outcome measures for men who are undergoing focal therapy for localized prostate cancer. The level of agreement achieved will pave the way for future collaborative trials.

Maximum tumor diameter: a simple independent predictor for biochemical recurrence after radical prostatectomy

Previous studies have suggested that maximum tumor diameter (MTD) is a predictor of PSA recurrence or biochemical recurrence (BCR) in prostate cancer after radical prostatectomy (RP). The significance of MTD in BCR prediction was evaluated using RP specimens of 364 patients with a BCR of 18% (n=66) during a mean follow-up of 37.4 months (range: 10-109 months). MTD was defined as the largest diameter of the largest tumor, and its median MTD was 15 mm (range: 0.9-50 mm). MTD was significantly associated with pre-operative PSA levels, pathological T stage, Gleason's score and positive surgical margin. In a univariate analysis, pathological T stage, Gleason's score, positive surgical margin and MTD were associated significantly with the risk of BCR. Patients with >20 mm MTD had a significantly higher risk of BCR than did those with < or =20 mm MTD (P<0.001). Cox multivariate models indicated that pathological stage, Gleason's score, positive surgical margin and MTD were independent prognostic factors for BCR. MTD would be a useful tool for predicting BCR, as calculation of MTD is a simple and reliable measure.

Nerve growth factor signaling in prostate health and disease

The prostate is one of the most abundant sources of nerve growth factor (NGF) in different species, including humans. NGF and its receptors are implicated in the control of prostate cell proliferation and apoptosis and it can either support or suppress cell growth. The co-expression of both NGF receptors, p75(NGFR) and tropomyosin-related kinase A (trkA), represents a crucial condition for the antiproliferative effect of NGF; indeed, p75(NGFR) is progressively lost during prostate tumorigenesis and its disappearance represents a malignancy marker of prostate adenocarcinoma (PCa). Interestingly, a dysregulation of NGF signal transduction was found in a number of human tumors. This review summarizes the current knowledge on the role of NGF and its receptors in prostate and in PCa. Conclusions bring to the hypothesis that the NGF network could be a candidate for future pharmacological manipulation in the PCa therapy: in particular the re-expression of p75(NTR) and/or the negative modulation of trkA could represent a target to induce apoptosis and to reduce proliferation and invasiveness of PCa.

Is focal therapy the future for prostate cancer?

Focal therapy aims to find a middle ground between surveillance and radical therapies by treating the cancer alone, with a margin, and preserving as much tissue as is practical. Early feasibility studies have demonstrated an absence of rectal toxicity and preservation of genitourinary function in 80–90% of men. The incidence of low- to intermediate-risk prostate cancer is rising owing to informal and formal prostate-specific antigen screening practices. The treatment burden from radical therapies is high with over 50% of men suffering genitourinary or rectal toxicity. Active surveillance, on the other hand, carries surveillance and psychological burden with risk of progression. A research strategy to evaluate focal therapy should be embedded within pragmatic designs using a broad patient group, using the available ablative technologies (cryotherapy, high-intensity focused ultrasound, brachytherapy and photodynamic therapy) with end points derived from biochemical, biopsy and imaging. Within this framework there exists a unique opportunity to undertake landmark diagnostic studies incorporating imaging techniques and biomarkers in addition to studies directed at the biology of prostate cancer over time.

Biopsy accuracy in identifying unilateral prostate cancer depends on prostate weight

OBJECTIVE

To evaluate the association between prostate weight and the diagnostic performance of routine biopsy schemes in detecting unilateral prostate cancer (PCa) that may be amenable to focal therapy.

METHODS AND MATERIALS

Retrospective analysis of patients undergoing radical prostatectomy at Duke University Medical Center from 1990 to 2007. The cohort was dichotomized according to prostate weight (≤40 and >40 g) and further divided by biopsy scheme: 6-9 (sextant) and 10-20 cores (extended). Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive values were calculated within each prostate weight group and compared between biopsy schemes.

RESULTS

A total of 859 patients were included in the study. Patients with prostates >40 g were generally older and had higher PSA levels (P < 0.0001 and P = 0.036, respectively). Unilateral disease was more common in prostates >40 g both on biopsy (69% vs. 60%, P = 0.009) and on final pathology (21% vs. 14%, P = 0.017) despite larger total tumor volume (6.1 vs. 4.8 cc, P < 0.001). Low grade PCa was also more common in larger glands (P = 0.003). Overall, extended biopsy schemes performed better than sextant but the benefit was statistically significant only in prostates >40 g.

CONCLUSIONS

Despite having higher tumor volumes, men with prostate weight >40 g were more likely to have unilateral PCa than those with smaller prostates. In prostates >40 g, increasing the number of cores harvested at biopsy increased the diagnostic performance for detecting cancer laterality. Therefore, our results suggest that the benefit of more extensive tissue sampling may be higher in larger prostates compared with smaller ones when selecting candidates for prostate hemiablation.