Pathologic stage T2a and T2b prostate cancer in the recent prostate-specific antigen era: implications for unilateral ablative therapy

Personalized Treatment Strategy in "Low-Risk Prostate Cancer Active Surveillance Candidates" Using Irreversible Electroporation: Prospective Evaluation of Feasibility, Morbidity, Functional and Oncological Outcomes

PURPOSE

To evaluate the morbidity, functional and oncological outcome of irreversible electroporation (IRE) as a focal therapy for prostate cancer (PCa) when used in "active surveillance (AS)" candidates refusing standard treatment options.

MATERIALS AND METHODS

IRE was performed under general anaesthesia, and the transurethral catheter was removed one day after intervention in all patients. Pre- and post-interventional voiding parameters (measured by International Prostate Symptom Score Questionnaire [IPSS], uroflowmetry and post-void residue) were compared. Follow-up (FU) was observed over a minimum of six months, including oncological outcome (controlled by multiparametric magnetic resonance imaging, rebiopsy, prostate-specific antigen dynamic as well as the need and type of secondary treatment) and general functional outcome (International Index of Erectile Function Questionnaire, satisfaction of the procedure).

RESULTS

Twenty-four patients refusing AS or standard treatment with a median FU of 18.7 months were included. IPSS showed nine patients with mild, 12 with moderate and two with severe obstructive voiding symptoms pre-intervention (focal IRE). Median IPSS pre-IRE was 9 points, 8.5 (p=0.341) at six months and 10 (p=0.392) after 12 months, respectively. Pre-IRE maximum urinary flow (Qmax) (median: 16.1±8.0 mL/sec) and Qmax after catheter removal (16.2±7.6 mL/sec) did not differ significantly (p=0.904). Thirteen PCa recurrences occurred (54.2%). Out-of-lesion-PCa was found in 12/13 patients (92.3%), while 4/13 patients showed in-lesion-PCa recurrence simultaneously (30.8%). In one patient, there was an in-lesion-PCa recurrence only (7.7%). Six out of 24 patients (25.0%) received a secondary treatment. All patients were satisfied with the IRE procedure.

CONCLUSIONS

Focal IRE underperforms regarding the overall oncological outcome and should not be offered as an equivalent therapy to established curative treatment strategies. Nevertheless, under a strict FU regimen, its lack of significant additional morbidity compared to an active surveillance strategy makes IRE a feasible alternative for low-risk PCa in highly selected patients as a personalised approach.

Evolution of Focal Therapy in Prostate Cancer: Past, Present, and Future

Organ sparing approaches for the management of localized prostate cancer were developed in part to overcome the morbidity associated with standard, whole gland treatment options. The first description of focal therapy was now over two decades ago and since that time much has changed. The evolution of patient selection, the approach to ablation, and surveillance after focal therapy have mirrored the technologic advancements in the field as well as the improved understanding of the biology of low-grade, low-risk prostate cancer. This review presents the evidence for the basis of focal therapy from the past to the present and future endeavors.

T2*-weighted MRI as a non-contrast-enhanced method for assessment of focal laser ablation zone extent in prostate cancer thermotherapy

OBJECTIVES

To evaluate utility of T2*-weighted (T2*W) MRI as a tool for intra-operative identification of ablation zone extent during focal laser ablation (FLA) of prostate cancer (PCa), as compared to the current standard of contrast-enhanced T1-weighted (T1W) MRI.

METHODS

Fourteen patients with biopsy-confirmed low- to intermediate-risk localized PCa received MRI-guided (1.5 T) FLA thermotherapy. Following FLA, axial multiple-TE T2*W images, diffusion-weighted images (DWI), and T2-weighted (T2W) images were acquired. Pre- and post-contrast T1W images were also acquired to assess ablation zone (n = 14) extent, as reference standard. Apparent diffusion coefficient (ADC) maps and subtracted contrast-enhanced T1W (sceT1W) images were calculated. Ablation zone regions of interest (ROIs) were outlined manually on all ablated slices. The contrast-to-noise ratio (CBR) of the ablation site ROI relative to the untreated contralateral prostate tissue was calculated on T2*W images and ADC maps and compared to that in sceT1W images.

RESULTS

CBRs in ablation ROIs on T2*W images (TE = 32, 63 ms) did not differ (p = 0.33, 0.25) from those in sceT1W images. Bland-Altman plots of ROI size and CBR in ablation sites showed good agreement between T2*W (TE = 32, 63 ms) and sceT1W images, with ROI sizes on T2*W (TE = 63 ms) strongly correlated (r = 0.64, p = 0.013) and within 15% of those in sceT1W images.

CONCLUSIONS

In detected ablation zone ROI size and CBR, non-contrast-enhanced T2*W MRI is comparable to contrast-enhanced T1W MRI, presenting as a potential method for intra-procedural monitoring of FLA for PCa.

KEY POINTS

• T2*-weighted MR images with long TE visualize post-procedure focal laser ablation zone comparably to the contrast-enhanced T1-weighted MRI. • T2*-weighted MRI could be used as a plausible method for repeated intra-operative monitoring of thermal ablation zone in prostate cancer, avoiding potential toxicity due to heating of contrast agent.

Focal bipolar radiofrequency ablation for localized prostate cancer: Safety and feasibility

OBJECTIVES

To evaluate the safety and feasibility of focal bipolar radiofrequency ablation in men with localized prostate cancer.

METHODS

A review of 10 patients treated with a novel bipolar radiofrequency ablation probe integrated in a coil design (Encage; Trod Medical, Bradenton, FL, USA) between 2011 and 2017 in two prospective pilot trials. All men had clinical stage T1c prostate cancer, prostate-specific antigen <10 ng/mL and Gleason score ≤7. Ablation was carried out under general anesthesia, and bipolar probes were inserted transperineally under transrectal ultrasound guidance. Treatment-related adverse events, quality of life and negative biopsy rate were evaluated at 6 months after ablation. The Wilcoxon signed-rank test was used to compare baseline and post-treatment symptom scores.

RESULTS

The median age was 58 years (range 50-64 years) and the median prostate volume was 49.65 cc (range 21-68 cc). Prostate cancer with a Gleason score of 6 (3 + 3) and 7 (3 + 4) was noted in seven and three patients, respectively. The median number of radiofrequency ablation cycles was 2.5 (range 2-5). All patients were catheter-free and able to void the day of surgery. Within 6 months after ablation, all adverse events were low grade, with the exception of one grade 3 hematuria that required cystoscopy without coagulation. Six months after ablation bowel, urinary and hormonal functions, and overall satisfaction remained stable. Erectile dysfunction occurred in two out of four patients who had normal sexual function before the procedure. Neither urinary incontinence nor urinary infection was noted.

CONCLUSIONS

This first report on focal bipolar radiofrequency ablation documents a safe and feasible treatment option for selected patients with localized prostate cancer.

Comparison of T2-Weighted Imaging, DWI, and Dynamic Contrast-Enhanced MRI for Calculation of Prostate Cancer Index Lesion Volume: Correlation With Whole-Mount Pathology

OBJECTIVE

The objective of our study was to investigate the comparative effectiveness of different MRI sequences for the estimation of index lesion volume in patients with prostate cancer (PCa) compared with ground truth volume measured on whole-mount pathology.

MATERIALS AND METHODS

Patients with PCa underwent multiparametric MRI (mpMRI) on a 3-T MRI scanner before radical prostatectomy. Forty PCa index lesions were identified and outlined on histology by a pathologist. Two radiologists who were informed about the presence of PCa but were not aware of lesion outlines on histology worked in consensus to delineate PCa lesions on T2-weighted imaging, apparent diffusion coefficient (ADC) maps, and early-phase dynamic contrast-enhanced MRI (DCE-MRI). The lesion volumes from different mpMRI sequences and the percentage of volume underestimation compared with pathology were calculated and correlated with volume at pathology. The repeated-measures ANOVA with the posthoc Bonferroni test was performed to evaluate whether the difference between the estimated tumor volumes was statistically significant.

RESULTS

The mean PCa lesion volume estimated from pathology, T2-weighted imaging, DWI (ADC maps), and DCE-MRI were 4.61 ± 4.99 (SD) cm³, 2.03 ± 2.96 cm³, 1.81 ± 2.76 cm³, and 3.48 ± 4.06 cm³, respectively. The lesion volumes on T2-weighted images (p = 0.000002), ADC maps (p = 0.000003), and DCE-MR images (p = 0.004412) were significantly lower than those from pathology. PCa lesion volume was significantly underestimated on T2-weighted images, ADC maps, and DCE-MR images compared with pathology by 54.98% ± 22.60% (mean ± SD), 58.59% ± 18.58%, and 18.33% ± 30.11%, respectively; underestimation using T2-weighted imaging (p = 1.01 × 10^-11) and DWI (p = 2.94 × 10^-11) was significantly higher than underestimation using DCE-MRI. Correlations between lesion volume estimated on T2-weighted images, ADC maps, and DCE-MR images with pathology were 0.91 (p = 9.03 × 10^-16), 0.86 (p = 7.32 × 10^-13), and 0.93 (p = 8.22 × 10^-18), respectively.

CONCLUSION

DCE-MRI performed better than T2-weighted imaging and DWI for estimation of index PCa volume and therefore can be preferred over these other two sequences for volume estimation.

Radiofrequency heat-enhanced direct intratumoral chemotherapy for prostate cancer

A novel, minimally invasive interventional technique, radiofrequency heat (RFH), has been suggested to improve the efficacy of chemotherapy for solid organ tumors. However, the treatment for prostate cancer has not been completely characterized. The aim of the present study was to investigate the in vitro and in vivo efficiency of chemotherapy in combination with RFH for the treatment of prostate cancer. The following four treatment groups were included: i) No treatment (control); ii) RFH-only; iii) chemotherapy (docetaxel)-only; and iv) combination therapy of docetaxel and RFH in human prostate cancer (HPC) cell lines and mice with HPC xenografts. In the in vitro experiments, a heating guidewire was attached under the bottom of the last chamber of the four-chamber cell culture slide, and was then connected to a radiofrequency (RF) generator. In the in vivo experiments, a tumor model was generated by subcutaneously injecting human prostate cancer cells into 24 male nu/nu mice. RFH was conducted by inserting the 0.022-inch heating-guidewire into the tumor. The follow-up magnetic resonance imaging demonstrated a significant reduction in the average tumor size in animals treated with combination therapy compared with those receiving RFH-only and chemotherapy-only. The number of apoptotic cells and the average apoptotic index of the combination therapy group were significantly higher compared with those of the other three treatment groups. In conclusion, the results of the present study suggested that RFH is able to increase the therapeutic efficiency of docetaxel in prostate cancer, and this study serves as a foundation for the future development of an interventional molecular image-guided local treatment strategy for prostate cancer that integrates RF technology, interventional oncology and direct intratumoral chemotherapy, as a replacement for systemic chemotherapy.

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.

Correlation of Peripheral Vein Tumour Marker Levels, Internal Iliac Vein Tumour Marker Levels and Radical Prostatectomy Specimens in Patients with Prostate Cancer and Borderline High Prostate-Specific Antigen: A Pilot Study

PURPOSE

To correlate prostate-specific antigen (PSA), free to total PSA percentage (fPSA%) and prostatic acid phosphatase (PAP) levels from peripheral and pelvic venous samples with prostatectomy specimens in patients with prostate adenocarcinoma and borderline elevation of PSA.

MATERIALS AND METHODS

In this prospective institutional review board approved study, 7 patients with biopsy proven prostate cancer had a venous sampling procedure prior to prostatectomy (mean 3.2 days, range 1-7). Venous samples were taken from a peripheral vein (PVS), the right internal iliac vein, a deep right internal iliac vein branch, left internal iliac vein and a deep left internal iliac vein branch. Venous sampling results were compared to tumour volume, laterality, stage and grade in prostatectomy surgical specimens.

RESULTS

Mean PVS PSA was 4.29, range 2.3-6 ng/ml. PSA and PAP values in PVS did not differ significantly from internal iliac or deep internal iliac vein samples (p > 0.05). fPSA% was significantly higher in internal iliac (p = 0.004) and deep internal iliac (p = 0.003) vein samples compared to PVS. One of 7 patients had unilateral tumour only. This patient, with left-sided tumour, had a fPSA% of 6, 6, 6, 14 and 12 in his peripheral, right internal iliac, deep right internal iliac branch, left internal iliac and deep left internal iliac branch samples respectively. There were no adverse events.

CONCLUSION

fPSA%, unlike total PSA or PAP, is significantly higher in pelvic vein compared to peripheral vein samples when prostate cancer is present. Larger studies including patients with higher PSA values are warranted to further investigate this counterintuitive finding.

Focal therapy for prostate cancer: The current status

Purpose

In an era of increasing prostate cancer incidence and earlier detection, the assessment of clinical significance of prostate cancer is critical. Minimally invasive therapies are increasingly being investigated in localized prostate cancer.

Methods and results

In this review, we discuss the current status of magnetic resonance imaging targeted fusion prostate biopsy and focal therapy for prostate cancer, its rationale, and techniques.

Conclusion

Focal therapy offers a promising outlook for prostate cancer treatment, with the goal of effectively achieving cancer control while minimizing morbidity. Long term studies are needed.

Recent advances in imaging-guided interventions for prostate cancers

The numbers of patients diagnosed with prostate cancers is increasing due to the widespread application of prostate-specific antigen screening and subsequent prostate biopsies. The methods of systemic administration of therapeutics are not target-specific and thus cannot efficiently destroy prostate tumour cells while simultaneously sparing the surrounding normal tissues and organs. Recent advances in imaging-guided minimally invasive therapeutic techniques offer considerable potential for the effective management of prostate cancers. An objective understanding of the feasibility, effectiveness, morbidity, and deficiencies of these interventional techniques is essential for both clinical practice and scientific progress. This review presents the recent advances in imaging-guided interventional techniques for the diagnosis and treatment of prostate cancers.

The role of focal therapy in the management of localised prostate cancer: a systematic review

CONTEXT

The incidence of localised prostate cancer is increasing worldwide. In light of recent evidence, current, radical, whole-gland treatments for organ-confined disease have being questioned with respect to their side effects, cancer control, and cost. Focal therapy may be an effective alternative strategy.

OBJECTIVE

To systematically review the existing literature on baseline characteristics of the target population; preoperative evaluation to localise disease; and perioperative, functional, and disease control outcomes following focal therapy.

EVIDENCE ACQUISITION

Medline (through PubMed), Embase, Web of Science, and Cochrane Review databases were searched from inception to 31 October 2012. In addition, registered but not yet published trials were retrieved. Studies evaluating tissue-preserving therapies in men with biopsy-proven prostate cancer in the primary or salvage setting were included.

EVIDENCE SYNTHESIS

A total of 2350 cases were treated to date across 30 studies. Most studies were retrospective with variable standards of reporting, although there was an increasing number of prospective registered trials. Focal therapy was mainly delivered to men with low and intermediate disease, although some high-risk cases were treated that had known, unilateral, significant cancer. In most of the cases, biopsy findings were correlated to specific preoperative imaging, such as multiparametric magnetic resonance imaging or Doppler ultrasound to determine eligibility. Follow-up varied between 0 and 11.1 yr. In treatment-naïve prostates, pad-free continence ranged from 95% to 100%, erectile function ranged from 54% to 100%, and absence of clinically significant cancer ranged from 83% to 100%. In focal salvage cases for radiotherapy failure, the same outcomes were achieved in 87.2-100%, 29-40%, and 92% of cases, respectively. Biochemical disease-free survival was reported using a number of definitions that were not validated in the focal-therapy setting.

CONCLUSIONS

Our systematic review highlights that, when focal therapy is delivered with intention to treat, the perioperative, functional, and disease control outcomes are encouraging within a short- to medium-term follow-up. Focal therapy is a strategy by which the overtreatment burden of the current prostate cancer pathway could be reduced, but robust comparative effectiveness studies are now required.

Prostate saturation biopsy following a first negative biopsy: state of the art

INTRODUCTION

Saturation prostate biopsy (SPBx) has been initially introduced to improve prostate cancer (PCa) detection rate (DR) in the repeat setting. Nevertheless, the optimal number and the most appropriate location of the cores, together with the timing to perform a second PBx and the eventual modification of the PBx protocols according to the different clinical situations, are matters of debate. The aim of this review is to perform a critical analysis of the literature about the actual role of SPBx in the repeat setting.

MATERIALS AND METHODS

We performed a systematic review of the literature since 1995 up to 2011. Electronic searches were limited to the English language, using the MEDLINE database. The key words 'saturation prostate biopsy' and 'repeated prostate biopsy' were used.

RESULTS

SPBx improves PCa DR if clinical suspicion persists after previous biopsy with negative findings and provides an accurate prediction of prostate tumor volume and grade, even if the issue about the number and locations of the cores is still a matter of debate.

CONCLUSIONS

At present, SPBx seems to be really necessary in men with persistent suspicion of PCa after negative initial biopsy and probably in patients with a multifocal high-grade prostatic intraepithelial neoplasia or atypical small acinar proliferation. In the remaining situations, adopting an individualized scheme is preferable.

There is no way to identify patients who will harbor small volume, unilateral prostate cancer at final pathology. implications for focal therapies

BACKGROUND

The aim of this study was to assess the clinical characteristics of the potentially ideal candidates for focal therapy, that is, patients with unilateral, small volume (namely, pT2a) prostate cancer (PCa) at radical prostatectomy (RP).

MATERIALS AND METHODS

We evaluated 2,503 consecutive pT2 PCa patients treated with RP between 2002 and 2009 at a single center. Within this population, the clinical characteristics of patients with pT2a and pT2b/c disease were compared. Univariable and multivariable logistic regression models were fitted to assess clinical predictors of pT2a at RP.

RESULTS

Overall, 349 patients (14%) had pT2a PCa, while the remaining patients had either pT2b (n = 334; 15.5%) or pT2c disease (n = 1,820 patients; 84.5%). Patients with pT2a PCa had a significantly lower mean PSA value, lower mean percentage of positive biopsy cores and lower biopsy Gleason score distribution (all P ≤ 0.03). However, at multivariable analyses, only percentage of positive cores maintained an independent predictor status (P = 0.01). Even when considering only patients sharing all the most favorable PCa characteristics (namely, clinical stage T1, PSA ≤ 4, Gleason score ≤6 and percentage of positive cores ≤25%), the rate of pT2a disease was only 24%.

CONCLUSIONS

The rate of small volume, unilateral PCa even among patients with extremely favourable PCa characteristics was remarkably low (roughly 25%). This suggests that: (1) Three quarters of the best candidates for focal therapy would ultimately show adverse pathological features; (2) At present, accurate identification of the ideal candidate for focal therapy is not possible with current clinical-pathologic parameters.

Management of Localized Prostate Cancer by Focal Transurethral Resection of Prostate Cancer: An Application of Radical TUR-PCa to Focal Therapy

Background. We analyzed radical TUR-PCa against localized prostate cancer. Patients and Methods. Seventy-nine out of 209 patients with prostate cancer in one lobe were studied. Patients' age ranged from 58 to 91 years and preoperative PSA, 0.70 to 17.30 ng/mL. In other 16 additional patients we performed focal TUR-PCa. Patients' age ranged from 51 to 87 years and preoperative PSA, 1.51 to 25.74 ng/mL. Results. PSA failure in radical TUR-PCa was 5.1% during the mean follow-up period of 58.9 months. The actuarial biochemical non-recurrence rate was 98.2% for pT2a and 90.5% for pT2b. Bladder neck contracture occurred in 28 patients (35.4%). In 209 patients, pathological study revealed prostate cancer of the peripheral zone near the neurovascular bundle bilaterally in 25%, unilaterally in 39% and no cancer bilaterally in 35%, suggesting the possibility of focal TUR-PCa. Postoperative PSA of 16 patients treated by focal TUR-PCa was stable between 0.007 and 0.406 ng/mL at 24.2 months' follow-up. No patients suffered from urinary incontinence. Bladder neck contracture developed in only 1 patient and all 5 patients underwent nerve-preserving TUR-PCa did not show erectile dysfunction. Conclusion. Focal TUR-PCa was considered to be a promising option among focal therapies against localized prostate cancer.

Current Challenges in Prostate Cancer Management and the Rationale behind Targeted Focal Therapy

Among men, prostate cancer has a high prevalence, with relatively lower cancer-specific mortality risk compared to lung and colon cancer. Prostate-specific antigen (PSA) screening has increased prostate cancer awareness since its implementation as a screening tool almost 25 years ago, but, due to the largely indolent course of this disease and the unspecific nature of the PSA test, increased incidence has largely been associated with cancers that would not go on to cause death (clinically insignificant), leading to an overdiagnosis challenge and an ensuing overtreatment consequences. The overtreatment problem is exacerbated by the high risk of side effects that current treatment techniques have, putting patients' quality of life at risk with little or no survival benefit. The goals of this paper are to evaluate the rise, prevalence, and impact of the overdiagnosis and ensuing overtreatment problems, as well as highlight potential solutions. In this effort, a review of major epidemiological and screening studies, cancer statistics from the advent of prostate-specific antigen screening to the present, and reports on patient concerns and treatment outcomes was conducted to present the dominant factors that underlie current challenges in prostate cancer treatment and illuminate potential solutions.

Evolution of the clinical presentation of men undergoing radical prostatectomy for high-risk prostate cancer

OBJECTIVE

To investigate the outcomes and potential effect of improved longitudinal screening in men presenting with high-risk (advanced clinical stage [>T2b], Gleason score 8-10 or prostate-specific antigen [PSA] level >20 ng/mL) prostate cancer (PC).

PATIENTS AND METHODS

The Institutional Review Board approved, Institutional Radical Prostatectomy Database (1992-2010) was queried for men with high-risk PC based on D'Amico criteria. Year of surgery was divided into two cohorts: the Early PSA Era (EPE, 1992-2000) and the Contemporary PSA Era (CPE, 2001-2010). PC features and outcomes were evaluated using appropriate comparative tests.

RESULTS

In total, 667 men had high-risk PC in the EPE and 764 in the CPE. In the EPE, 598 (89.7%) men presented with one high-risk feature; 173 (29.0%) men had a Gleason score of 8-10 on biopsy. In the CPE, 717 (93.9%) men presented with one high-risk feature (P = 0.004) and 494 (68.9%) men had a Gleason score of 8-10. At 10 years, biochemical-free survival (BFS) was 44.1% and 36.4% in the EPE and CPE, respectively (P = 0.04); metastases-free survival (MFS) was 77.1% and 85.1% (P = 0.6); and PC-specific survival (CSS) was 83.3% and 96.2% (P = 0.5). BFS, MFS and CSS were worse for men with more than one high-risk feature in both eras.

CONCLUSIONS

Over the PSA era, an increasing percentage of men with high-risk PC were categorized by a biopsy Gleason score of 8-10. The accumulation of multiple high-risk features increases the risk of biochemical recurrence, the development of metastases and death from PC. BFS, MFS and CSS are stable over the PSA era for these men. The balance between a greater proportion of men having high Gleason disease and a greater proportion with small, less advanced tumours may explain the stability in MFS and CSS over time.

Pros and cons of focal therapy for localised prostate cancer

In prostate cancer, an interesting and intriguing option to overcome the risks of whole-gland treatment is focal therapy, with the aim of eradicating known cancer foci and reducing collateral damages to the structures essential for maintaining normal urinary and sexual function. Ablation of all known lesions would favorably alter the natural history of the cancer without impacting health-related quality of life and allows for safe retreatment with repeated focal therapy or whole-gland approaches if necessary. Our objective is to reassess the possibilities and criticisms of such procedure: the rationale for focal therapy and the enthusiasm come from the success of conservative approaches in treating other malignancies and in the high incidence of overtreatment introduced by prostate cancer screening programs. One of the challenges in applying such an approach to the treatment of prostate cancer is the multifocal nature of the disease and current difficulties in accurate tumor mapmaking.

Pathological T2 sub-divisions as a prognostic factor in the biochemical recurrence of prostate cancer

OBJECTIVE

To determine the adequacy of T2 prostate cancer (PCa) sub-staging as an independent Predictor of biochemical disease-free survival (bDFS) after radical prostatectomy.

MATERIALS AND METHODS

The Duke Prostate Center database was queried for patients who underwent radical prostatectomy between 1988 and 2007 and had pT2 PCa, identifying 1990 cases. Prostate-specific antigen (PSA) recurrence was defined as a single value ≥0.2 ng/mL. Kaplan-Meier curves compared differences in bDFS between T2 sub-divisions. Multivariate analysis was performed, adjusting for age, pathological Gleason sum, surgical margin status, preoperative PSA, race, total tumour percentage and prostate weight on biochemical recurrence.

RESULTS

The mean age at surgery was 62 years, and 16% of patients were African-American. Median prostate weight was 40 g [interquartile range (IQR) 31-52] and median preoperative PSA was 5.6 (IQR 4.2-7.8). Pathological Gleason score was ≤6 in 57%, 7 in 38%, and ≥8 in 5%; pathological T stage distribution was 18% T2a, 6% T2b, and 76% T2c; and percentage tumour involvement was ≤5% in 43%, between 5.1 and 10% in 24%, between 10.1 and 15% in 10%, and >15% in 19%. 366 (18.4%) patients had a biochemical recurrence after a median of 4.6 years (IQR 2.1-8.2) follow-up. bDFS was significantly (P= 0.006) higher for pT2a disease than for pT2b and pT2c, which were comparable. Adjusting for demographic and other pathological variables, T2 sub-divisions lost statistical significance.

CONCLUSIONS

Pathological T2a prostate cancer has significantly higher bDFS than the pT2b or pT2c sub-groups in univariate but not multivariate analyses. Different pathological features should be explored to create more meaningfully predictive pathological T2 sub-divisions.

Tumor focality in prostate cancer: implications for focal therapy

In recent years, there has been a growing interest in focal treatment for prostate cancer. Although widely used for the treatment of tumors of the breast and kidney, focal treatment for prostate cancer remains a controversial area. Criticism of focal prostate therapy has been based on the fact that prostate cancer is a multifocal disease. Until now, little attention has been paid to distinguishing between men with unifocal and those with multifocal disease because such information has little clinical relevance when treatment is aimed at the whole gland irrespective of the volume or number of cancers in the prostate. In this Review, we summarize existing knowledge and examine the issue of prostate cancer focality in the context of focal treatment.

The role of transrectal saturation biopsy in tumour localization: pathological correlation after retropubic radical prostatectomy and implication for focal ablative therapy

OBJECTIVE

• To evaluate the accuracy of an initial 24-core prostate biopsy scheme (PBx24) in predicting unilateral prostate cancer (PCa) in radical prostatectomy (RP) specimens.

PATIENTS AND METHODS

• Between 2005 and 2008, 203 consecutive patients underwent PBx24 followed by RP for PCa. The area under the curve (AUC) was used to evaluate the accuracy of unilateral PCa on PBx24 to predict unilateral PCa in RP specimens. • The positive predictive value (PPV) and negative predictive value (NPV) were also calculated. Moreover, in patients with unilateral PCa on biopsy, univariable and multivariable logistic regression analyses tested the relationship between the presence of unilateral PCa in an RP specimen and the variables: age, prostate-specific antigen (PSA), total prostate volume, clinical stage, primary Gleason grade, secondary Gleason grade and the number of positive cores.

RESULTS

• PCa cores were unilateral in 115 patients (56.7%) on biopsy. Of those, only 26 (22.6%) had unilateral PCa in the RP specimen (AUC, 72.9%; PPV, 22.6%; NPV, 98.8%). In patients with clinically low-risk tumours, only 17 of 63 (27%) had a unilateral PCa on PBx24 and in the RP specimen (AUC, 59.1%; PPV, 27.0%; NPV, 100.0%). • None of the examined variables was an independent predictor of the presence of unilateral PCa in the RP specimen (all P > 0.05).

CONCLUSIONS

• Initial PBx24 is not sufficiently accurate to be dependable as a method of predicting tumour laterality in RP specimens. Therefore, the use of PBx24 to guide hemi-ablation therapy of PCa may lead to mistreatment in a considerable proportion of patients. • Moreover, none of the routinely available clinical and pathological characteristics appears to improve the ability of unilateral PCa on biopsy to predict unilateral PCa in the RP specimen.

Diffusion-weighted magnetic resonance imaging in patients with unilateral prostate cancer on extended prostate biopsy: predictive accuracy of laterality and implications for hemi-ablative therapy

PURPOSE

We evaluated the ability of extended prostate biopsy to detect unilateral prostate cancer and assessed the incremental diagnostic benefit of diffusion-weighted magnetic resonance imaging to predict unilateral prostate cancer.

MATERIALS AND METHODS

A total of 130 patients with prostate cancer detected by extended pattern prostate biopsy underwent magnetic resonance imaging before radical prostatectomy. Tumor laterality on extended prostate biopsy was compared with the corresponding lobe on the radical prostatectomy specimen. In patients with unilateral prostate cancer on biopsy we calculated the probability of a tumor in the contralateral lobe on magnetic resonance images and calculated area under the receiver operating characteristics curve. We compared the diagnostic accuracy of combined T2-weighted and diffusion-weighted magnetic resonance images to that of T2-weighted magnetic resonance images alone.

RESULTS

Of the 130 patients 88 (67.7%) had unilateral disease on extended prostate biopsy. Radical prostatectomy pathology showed that 19% of these patients had unilateral disease but 81% had bilateral disease. Area under the receiver operating characteristics curve of combined diffusion-weighted and T2-weighted magnetic resonance imaging was greater than that of T2-weighted magnetic resonance imaging alone (0.814, 95% CI 0.716-0.889 vs 0.510, 95% CI 0.401-0.618). T2-weighted plus diffusion-weighted magnetic resonance imaging had significantly higher sensitivity (84.1% vs 61.9%, p = 0.003) and specificity (72.0% vs 36.0%, p = 0.004) to predict cancer in the contralateral lobe than T2-weighted magnetic resonance alone.

CONCLUSIONS

Extended prostate biopsy cannot accurately determine prostate cancer unilaterality. Diffusion-weighted magnetic resonance combined with T2-weighted magnetic resonance imaging has an incremental diagnostic benefit to predict unilateral prostate cancer.

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.

Current status of MRI for the diagnosis, staging and prognosis of prostate cancer: implications for focal therapy and active surveillance

PURPOSE OF REVIEW

To review the current status of MRI techniques in identification of organ-confined prostate cancer with a focus on their implication for focal therapy and active surveillance.

RECENT FINDINGS

MRI is currently focusing on intraprostatic prostate cancer identification and at 1.5T, it provides excellent imaging of the whole gland including the challenging anterior part. Improvements in accuracy for cancer detection and volume estimation result from dynamic contrast-enhanced and diffusion-weighted MRI sequences. 3T MRI might improve cancer identification. Histological correlations showed high sensitivity and specificity for significant volume cancers larger than 0.5 cm3. Important knowledge on modelling of cancer morphology such as zone of origin and intraprostatic patterns of spread at histopathology was made available for imaging interpretation and treatment planning decision. MRI results allow focused use of biopsy which led to better cancer characterization such as extent and grade. Ongoing focal therapy protocols and active surveillance treatments should benefit from these imaging advances.

SUMMARY

At present, high-resolution MRI with pelvic coil appears to offer the most readily available and useful imaging. Future studies should work towards helping define standard, reproducible approaches to imaging and image reporting for research and clinical practice.

Decreasing use of luteinizing hormone-releasing hormone agonists in the United States is Independent of Reimbursement Changes: A Medicare and Veterans Health Administration claims analysis

PURPOSE

Luteinizing hormone-releasing hormone agonists are the most common form of androgen deprivation therapy in men with prostate cancer. Limited data exist regarding physician decision-making in prescribing luteinizing hormone-releasing hormone agonists. We present an analysis of luteinizing hormone-releasing hormone agonist use trends based on a time matched comparison of data from Medicare and the Veterans Health Administration, a health care system unaffected by recent changes in Medicare reimbursement implemented by the Medicare Modernization Act in 2004.

MATERIALS AND METHODS

Medicare claims and payment data were obtained from the Centers for Medicare and Medicaid Services from 2003 to 2007 for luteinizing hormone-releasing hormone agonists and for simple orchiectomy. The Veterans Health Administration Pharmacy Benefits Management database was queried for the annual number of prescriptions for luteinizing hormone-releasing hormone agonists during the same period.

RESULTS

After implementation of the Medicare Prescription Drug, Improvement and Modernization Act in 2004 the reimbursement of luteinizing hormone-releasing hormone agonists in the Medicare population decreased by 54.8% and annual claims decreased by 25.1% from 2004 to 2007. During the same period luteinizing hormone-releasing hormone agonist use decreased by 16.8% in the Veterans Health Administration population. There was no compensatory increase in the use of simple orchiectomy for androgen deprivation therapy during the study period.

CONCLUSIONS

Use of luteinizing hormone-releasing hormone agonists has decreased in the Medicare and Veterans Health Administration populations since 2004 without a compensatory increase in the use of alternative forms of androgen deprivation therapy. The shift in practice patterns is likely due to a decrease in Medicare reimbursement for these drugs, an increase in the use of intermittent therapy and increased recognition of the adverse effects associated with androgen deprivation therapy.

Can the conventional sextant prostate biopsy accurately predict unilateral prostate cancer in low-risk, localized, prostate cancer?

We evaluate the reliability of routine sextant prostate biopsy to detect unilateral lesions. A total of 365 men with complete records including all clinical and pathologic variables who underwent a preoperative sextant biopsy and subsequent radical prostatectomy (RP) for clinically localized prostate cancer at our medical center between January 1996 and December 2006 were identified. When the sextant biopsy detects unilateral disease, according to RP results, the NPV is high (91%) with a low false negative rate (9%). However, the sextant biopsy has a PPV of 28% with a high false positive rate (72%). Therefore, a routine sextant prostate biopsy cannot provide reliable, accurate information about the unilaterality of tumor lesion(s).

Nerve-sparing focal cryoablation of prostate cancer

PURPOSE OF REVIEW

We evaluate the rationale, candidate selection, and results of the first clinical studies of focal cryoablation for select patients with low volume and low-to-low - moderate risk features of prostate cancer as a possible alternative to whole gland treatment.

RECENT FINDINGS

For a select cohort of patients with low-to-low - moderate risk unifocal or unilateral prostate cancer, a number of ablative treatment options for focal therapy are available with cryotherapy having the most clinical experience. However, retrospective pathological data from large prostatectomy series do not clearly reveal valid and reproducible criteria to select appropriate candidates for focal cryoablation due to the complexity of tumorigenesis in early stage disease.

SUMMARY

The concept of focal therapy is evolving with the understanding of the biologic variability (clinically aggressive, significant, or insignificant) of prostate cancers that may require different treatment approaches. Minimally-invasive, parenchyma-preserving cryoablation can be considered as a potential feasible option in the treatment armamentarium of early stage, localized prostate cancer in appropriately selected candidates.

Prostate cancer: the new landscape

PURPOSE OF REVIEW

This review highlights current features of the changing landscape of the US population with newly diagnosed prostate cancer and discusses new treatment options utilizing noninvasive or minimally invasive management.

RECENT FINDINGS

Recent evidence of significant changes in the current prostate cancer landscape is based on clinical data and pathological specimens after radical prostatectomy that suggest a further increase of the low-risk patient population that may require reconsideration of treatment options. For a select cohort of patients with low-risk features, based on the D'Amico definition, active surveillance or focal ablative therapy may be a rational alternative to surgical prostatectomy or whole-gland radiation therapy that still dominate as the main treatment approaches for localized prostate cancer.

SUMMARY

As the prostate-specific antigen era continues to mature, we continue to witness stage migration. A growing segment of the localized prostate cancer patient population has very low-volume, low-grade disease. Although active surveillance may be an appropriate approach for a selected group of patients, the progression requiring whole-gland therapy remains a challenge. Organ-sparing focal therapy might ideally fill the gap between a surveillance strategy and whole-gland treatment providing a reasonable balance between cancer control and quality of life.