Focal therapy in prostate cancer: determinants of success and failure

Comparative Healthcare Research Outcomes of Novel Surgery in prostate cancer (IP4-CHRONOS): A prospective, multi-centre therapeutic phase II parallel Randomised Control Trial

INTRODUCTION

Focal therapy (FT) targets individual areas of cancer within the prostate, providing oncological control with minimal side-effects. Early evidence demonstrates encouraging short-medium-term outcomes. With no randomized controlled trials (RCT) comparing FT to radical therapies, Comparative Healthcare Research Outcomes of Novel Surgery in prostate cancer (CHRONOS) will compare the cancer control of these two strategies.

PATIENTS AND METHODS

CHRONOS is a parallel phase II RCT for patients with clinically significant non-metastatic prostate cancer, dependent upon clinician/patient decision, patients will enrol into either CHRONOS-A or CHRONOS-B. CHRONOS-A will randomize patients to either radical treatment or FT. CHRONOS-B is a multi-arm, multistage RCT comparing focal therapy alone to FT with neoadjuvant agents that might improve the current focal therapy outcomes. An internal pilot will determine the feasibility of, and compliance to, randomization. The proposed definitive study plans to recruit and randomize 1190 patients into CHRONOS-A and 1260 patients into CHRONOS-B.

RESULTS

Primary outcome in CHRONOS-A is progression-free survival (transition to salvage local or systemic therapy, development of metastases or prostate-cancer-related mortality) and in CHRONOS-B is failure-free survival (includes the above definition and recurrence of clinically significant prostate cancer after initial FT). Secondary outcomes include adverse events, health economics and functional outcomes measured using validated questionnaires. CHRONOS is powered to assess non-inferiority of FT compared to radical therapy in CHRONOS-A, and superiority of neoadjuvant agents with FT in CHRONOS-B.

CONCLUSION

CHRONOS will assess the oncological outcomes after FT compared to radical therapy and whether neoadjuvant treatments improve cancer control following one FT session.

Magnetic Resonance Imaging Assessment After Therapy in Prostate Cancer

Prostate cancer is the fifth leading cause of death worldwide. A variety of treatment options is available for localized prostate cancer and may range from active surveillance to focal therapy or whole gland treatment, that is, surgery or radiotherapy. Serum prostate-specific antigen levels are an important tool to monitor treatment success after whole gland treatment, unfortunately prostate-specific antigen is unreliable after focal therapy. Multiparametric magnetic resonance imaging of the prostate is rapidly gaining field in the management of prostate cancer and may play a crucial role in the evaluation of recurrent prostate cancer. This article will focus on postprocedural magnetic resonance imaging after different forms of local therapy in patients with prostate cancer.

Hemiablation of Localized Prostate Cancer by High-Intensity Focused Ultrasound: A Series of 35 Cases

Prostate cancer (PrC) is one of the most common tumors diagnosed in men. The detection rate of localized PrC has been dramatically enhanced by screening and the development of visualization methods. There are currently several techniques for focal treatment available, among which the most interesting in our opinion is high-intensity focused ultrasound (HIFU). Currently, HIFU hemiablation of PrC is not an established treatment, although evidence of its effectiveness and safety is growing. We have been performing HIFU hemiablation since 2013 and here report our results to add to the evidence on the effectiveness of the technique. Between October 2013 and December 2016, we performed HIFU hemiablation of the prostate for a total of 35 patients with confirmed PrC stage <cT2a at our urology clinic and retrospectively examined duration of ablation, pre- and postoperative prostate-specific antigen (PSA) levels, prostate volume, erectile function, and dysuria. The mean duration of ablation was 22 min (10-35). The mean postoperative hospital stay was 4 days. None of the patients experienced serious complications. Postoperative PSA tests showed the greatest decrease after 3 months to 2.4 ng/mL on average (p < 0.001). The pathological focus seen on MRI before the procedure in each case was absent after 3 months. Control biopsy after 12 months revealed residual cancer in the contralateral lobe in 4 patients. The findings obtained during follow-up and from control biopsies indicate that the treatment was highly efficacious with a low rate of nonserious postoperative complications. HIFU hemiablation proved to be a reliable therapeutic modality for localized PrC and was associated with a low rate of complications and comparable risk of recurrence. Despite the fact that this method of treatment is currently experimental, the results of this case series and other studies indicate its feasibility and safety.

Focal therapy for localized prostate cancer: is there a "middle ground" between active surveillance and definitive treatment?

In recent years, it has come a long way in the diagnosis, treatment, and follow-up of prostate cancer. Beside this, it was argued that definitive treatments could cause overtreatment, particularly in the very low, low, and favorable risk group. When alternative treatment and follow-up methods are being considered for this group of patients, active surveillance is seen as a good alternative for patients with very low and low-risk groups in this era. However, it has become necessary to find other alternatives for patients in the favorable risk group or patients who cannot adopt active follow-up. In the light of technological developments, the concept of focal therapy was introduced with the intensification of research to treat only the lesioned area instead of treating the entire organ for prostate lesions though there are not many publications about many of them yet. According to the initial results, it was understood that the results could be good if the appropriate focal therapy technique was applied to the appropriate patient. Thus, focal therapies have begun to find their "middle ground" place between definitive therapies and active follow-up.

Prostate MR Imaging for Posttreatment Evaluation and Recurrence

Prostate multiparametric MR imaging (mpMRI) plays an important role in local evaluation after treatment of prostate cancer. After radical prostatectomy, radiation therapy, and focal therapy, mpMRI can be used to visualize normal post-treatment changes and to diagnose locally recurrent disease. An understanding of the various treatments and expected changes is essential for complete and accurate post-treatment mpMRI interpretation.

A Whole of Population, Multiuser Series of High-Intensity Focused Ultrasound for Management of Localized Prostate Cancer: Outcomes and Implications

PURPOSE

To determine the oncologic and complication outcomes of treatment of patients with localized prostate cancer by high intensity focused ultrasound (HIFU) for primary management of prostate cancer in a whole of population, multiuser series.

PATIENTS AND METHODS

We created a centralized database-accessible only by nonurologist researchers-within a cancer epidemiology center, after ethics approval from that institution. A single researcher prospectively entered baseline, treatment, and clinical/biochemical follow-up data from all patients treated with HIFU in the state of Victoria over the study period.

RESULTS

We accrued 108 patients, of whom 103 had been staged as having clinically localized disease. Ninety-three patients (86.1%) had low- or intermediate-risk prostate cancer. Forty-four patients (40.5%) had persistent mild urinary incontinence at 3 months after treatment, and 3 of these ultimately underwent further surgical procedures to correct incontinence. Twenty-seven patients (25%) additionally experienced occasions of urinary retention in the first 3 months after treatment because of passage of tissue. Twenty-nine patients had achieved a prostate-specific antigen level of <0.2 ng/mL at 3 months after HIFU. Fifty-six patients underwent post-HIFU prostate biopsy, and this was positive for residual cancer in 51 cases. Forty-five of the patients who had a positive post-HIFU biopsy underwent secondary treatment for prostate cancer.

CONCLUSION

Oncologic control and complication outcomes in this cohort were inferior to those previously reported for HIFU in single-user series. Given the population-based multiuser nature of our series, we believe our observations are more likely to reflect the community outcomes that might be expected from widespread adoption of HIFU than generalizing from single-operator series.

Image guidance in the focal treatment of prostate cancer

PURPOSE OF REVIEW

The advent of prostate-specific antigen screening has led to a seven-fold increase in the incidence of prostate cancer without a resultant decrease in mortality rate. This has led to the belief that urologists are overdetecting and overtreating clinically insignificant disease. To maintain the delicate balance between high cancer cure rate and overtreatment, which could potentially lead to unnecessary morbidities, focal therapy has emerged as the reasonable middle ground. In this article, we present the conceptual basis and the challenges of focal therapy, while emphasizing the critical role of imaging in focal treatment of prostate cancer.

RECENT FINDINGS

Multiple phase I trials have demonstrated the feasibility, short-term efficacy, and safety of focal therapy. Fundamental to the success of these trials and the ultimate acceptance of focal therapy is the integral role of imaging in optimal patient selection. Among the different imaging modalities, only ultrasound and multiparametric MRI are intimately involved in the detection, diagnosis, staging, and treatment of prostate cancer. Each modality has its own unique advantages and shortcomings. Recent advances in enhanced ultrasound modalities, functional MRIs, and biopsy platforms have taken focal therapy one step closer to becoming the standard of care.

SUMMARY

Although early results of phase I focal therapy trials are encouraging, long-term oncological outcomes remain to be elucidated. Incorporation of these technological advances into large prospective trials is needed to establish focal therapy as an important asset in the urologist's armamentarium against prostate cancer.

Advances in imaging and in non-surgical salvage treatments after radiorecurrence in prostate cancer: what does the oncologist, radiotherapist and radiologist need to know?

OBJECTIVES

In this article the state of art the of prostate cancer (Pca) imaging and non-surgical salvage treatments (STs) is surveyed in order to explore the impact of imaging findings on the identification of radiorecurrent Pca after external beam radiotherapy (EBRT).

METHODS

A computerised search was performed to identify all relevant studies in Medline up to 2012. Additional articles were extracted based on recommendations from an expert panel of authors.

RESULTS

Definitive EBRT for Pca is increasingly used as treatment. After radiorecurrent Pca, non-surgical STs are emerging and shifting from investigational status to more established therapeutic options. Therefore, several scientific societies have published guidelines including clinical and imaging recommendations, even if the timing, efficacy and long-term toxicity of these STs have to be established. In some measure, accurately delineating the location and the extent of cancer is critical in selecting target lesions and in identifying patients who are candidates for STs. However, there is increasing awareness that anatomical approaches based on measurements of tumour size have substantial limitations, especially for tumours of unknown activity that persist or recur following irradiation

CONCLUSIONS

To date, the main focus for innovations in imaging is the combination of excellence in anatomical resolution with specific biological correlates that depict metabolic processes and hallmarks at the tumour level. The emergence of new molecular markers could favour the development of methods that directly determine their presence, thereby improving tumour detection.

KEY POINTS

Imaging may influence therapeutic decisions during non-surgical STs. MRI findings correlate with parametric maps derived from multiple functional techniques. Non-surgical salvage treatments allow local tumour control in patients with radiorecurrent PCa.

Focal salvage therapy for localized prostate cancer recurrence after external beam radiotherapy: a pilot study

BACKGROUND

The objective of this study was to evaluate the safety, feasibility, side-effect profile, and proof of concept for focal salvage therapy using high-intensity focused ultrasound (HIFU).

METHODS

A registry-based analysis was conducted between 2004 and 2009 of 430 patients who underwent HIFU. Thirty-nine patients received focal salvage therapy for localized recurrence after external beam radiotherapy. Multiparametric magnetic resonance imaging studies combined with transperineal template prostate mapping biopsies or transrectal biopsies were used to localize disease. Validated questionnaires were used to assess functional outcomes. Biochemical failure was defined by using both Phoenix criteria (prostate-specific antigen [PSA] nadir plus 2 ng/mL) and Stuttgart criteria (PSA nadir plus 1.2 ng/mL).

RESULTS

The mean pre-HIFU PSA level was 4.6 ng/mL. The median follow-up was 17 months (interquartile range, 10-29 months). International Index of Erectile Function-5 scores decreased from a median ± standard deviation (SD) of 18 ± 16 to 13 ± 21 at 6 months, demonstrating worsening function. Scores on the University of California Los Angeles-Expanded Prostate Cancer Index Composite Urinary domain indicate that pad-free, leak-free continence status was 64%, and the pad-free rate was 87.2% at last follow-up. One rectourethral fistula occurred and spontaneously resolved with urinary and bowel diversion. The actuarial progression-free survival rate (including PSA nonresponders) was 69% at 1 year and 49% at 2 years according to Phoenix criteria. Excluding PSA nonresponders, these rates were 74% and 58%, respectively (Phoenix criteria).

CONCLUSIONS

The results from this study indicated that focal salvage therapy is a potential strategy for localized recurrence after radiotherapy that may reduce the harms resulting from whole-gland salvage therapies.

Transatlantic Consensus Group on active surveillance and focal therapy for prostate cancer

What's known on the subject? and What does the study add? Active surveillance for prostate cancer is gaining increasing acceptance for low risk prostate cancer. Focal therapy is an emerging tissue preservation strategy that aims for treat only areas of cancer. Early phase trials have shown that side-effects can be significantly reduced using focal therapy. There is significant uncertainty in both active surveillance and focal therapy. This consensus group paper provides a road-map for clinical practice and research for both tissue-preserving strategies in the areas of patient population, tools for risk stratification and cancer localisation, treatment interventions as well as comparators and outcome measures in future comparative trials.

OBJECTIVE

To reach consensus on key issues for clinical practice and future research in active surveillance and focal therapy in managing localized prostate cancer.

PATIENTS AND METHODS

A group of expert urologists, oncologists, radiologists, pathologists and computer scientists from North America and Europe met to discuss issues in patient population, interventions, comparators and outcome measures to use in both tissue-preserving strategies of active surveillance and focal therapy. Break-out sessions were formed to provide agreement or highlight areas of disagreement on individual topics which were then collated by a writing group into statements that formed the basis of this report and agreed upon by the whole Transatlantic Consensus Group.

RESULTS

The Transatlantic group propose that emerging diagnostic tools such as precision imaging and transperineal prostate mapping biopsy can improve prostate cancer care. These tools should be integrated into prostate cancer management and research so that better risk stratification and more effective treatment allocation can be applied. The group envisaged a process of care in which active surveillance, focal therapy, and radical treatments lie on a continuum of complementary therapies for men with a range of disease grades and burdens, rather than being applied in the mutually exclusive and competitive way they are now.

CONCLUSION

The changing landscape of prostate cancer epidemiology requires the medical community to re-evaluate the entire prostate cancer diagnostic and treatment pathway in order to minimize harms resulting from over-diagnosis and over-treatment. Precise risk stratification at every point in this pathway is required alongside paradigm shifts in our thinking about what constitutes cancer in the prostate.

Robotic prostate biopsy and its relevance to focal therapy of prostate cancer

Focal therapy is an individualized treatment option for prostate cancer, which destroys localized cancerous tissue but not normal tissue, thus avoiding the morbidities associated with whole-gland therapy. Accurate cancer localization and precise ablation are integral to the success of focal therapy, which remains unproven owing to suboptimal patient selection. Currently, there are no clinical or biopsy features that can identify unifocal prostate cancer and no imaging modality that can accurately diagnose or localize prostate cancer. MRI diagnosis has the best accuracy but high cost and limited access hinder its widespread adoption. New management options, including focal therapy and active surveillance, require prostate biopsy to detect, localize and characterize the cancer. Transrectal prostate biopsy has a high false-negative detection rate, which might be related to an inability to biopsy the anterior and apical part of the prostate or interoperator variation. Transrectal biopsy is also associated with sepsis and bleeding. Robotic transperineal prostate biopsy can overcome the limitations of transrectal procedures. Robotic biopsy is automated with high accuracy, has improved access to the apex and anterior part of the prostate and has low risk of sepsis. Furthermore, it involves only two skin punctures, compared with template-based transperineal prostate biopsy, which can result in multiple wounds. Robotic prostate biopsy fulfills the fundamental needs of focal therapy and might be the platform for future treatment delivery for prostate cancer.

Benchmarks for success in focal therapy of prostate cancer: cure or control?

BACKGROUND

The place of focal therapy in prostate cancer management requires further evaluation within randomized comparative clinical trials.

METHODS

This review article discusses the place of focal therapy and asks whether it is an alternative to active surveillance or radical therapy. This question therefore is at the heart of whether this proposed paradigm shift should be delivered with the intent of cure or cancer control.

RESULTS

For such trials to report on outcomes that have meaningful utility in the clinic, it is necessary to discuss whether focal ablation should be delivered with intent to eradicate all cancer foci ('cure') or ablate all clinically significant lesions with surveillance of all remaining tissue (benign or harboring clinically insignificant cancer). While the former will inevitably mean that fewer men will be appropriate for focal therapy were it to become standard care, it is the safest approach. The latter strategy will open focal therapy to the majority of men with low- to intermediate-risk disease with the potential of offering a treatment strategy that treats important cancer while preserving function with a high degree of probability.

CONCLUSION

A pragmatic randomized controlled clinical in which focal therapy is randomized against standard of care may be feasible. The pragmatic nature of such a trial would allow eligibility criteria, localization of cancer to reflect local practice (novel imaging and transrectal biopsy or template prostate mapping), and the focal intervention (ablative modality, intent to ablate all cancer foci or all clinically significant foci) to be kept broad to reflect clinical practice. Further, it would satisfy individual equipoise by allowing either active surveillance or radical therapy in the standard care arm, to be decided on by patient and physician.