Comparisons of oncological and functional outcomes among radical retropubic prostatectomy, high dose rate brachytherapy, cryoablation and high-intensity focused ultrasound for localized prostate cancer

Evaluation of functional and oncological outcomes of localized prostate cancer after different minimally invasive therapeutic methods: A single center experience

OBJECTIVES

To study the functional and oncological results of minimally invasive treatment methods: cryoablation, brachytherapy, and high-intensity focused ultrasound (HIFU) therapy of localized prostate cancer in a single hospital.

METHODS

One hundred sixty patients with localized prostate cancer were treated with minimally invasive methods (53, 52, 55 patients with cryoablation, brachytherapy and HIFU therapy, respectively). Prostate-specific antigen and evaluation of post-procedure biopsies were used as an assessment. The review of functional indicators and quality of life was made with International Index of Erectile Function (IIEF-5), International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax), quality of life (QoL) questionnaires.

RESULTS

Patients after cryoablation showed worse results of oncological control according to positive repeat biopsies, best indicators were observed after brachytherapy. When considering the IPSS results, there were statistically significantly worse scores in the brachytherapy group in the early postoperative period, these differences do not reach statistical significance in the late period in the brachytherapy and cryoablation groups. Patients in the cryoablation group showed worse indicators of IIEF-5; in the early postoperative period; in the late follow-up period, the indicators of erectile function in patients in the cryoablation group did not statistically significantly differ from those in patients after brachytherapy. Patients after HIFU therapy showed fewer cases of de novo erectile dysfunction during the follow-up period of 3 years, higher average IIEF-5 scores, lower IPSS scores and better QoL results.

CONCLUSION

The recurrence of prostate cancer was statistically significantly higher in the International Society of Urological Pathology (ISUP) 3 grade group. HIFU therapy had better urination indicators compared to other groups, that can be associated with the laser enucleation of prostatic hyperplasia. The advantage was noted in patients after HIFU therapy when comparing the parameters to the IIEF-5 thus, HIFU treatment had a better impact on patients' QoL with localized prostate cancer.

High-Intensity Focused Ultrasound (Sonablate®) for Prostate Cancer: Preliminary Outcomes in Taiwan

PURPOSE

We reported preliminary outcomes of high-intensity focused ultrasound (HIFU) [Sonablate®] in the combination of transurethral resection of the prostate for localized prostate cancer in Taiwan.

METHODS

Seventy-seven patients using Sonablate® HIFU for localized prostate cancer were enrolled in this study from April 2021 to December 2022. Prostate-specific antigen biochemical recurrence, International Index of Erectile Function (IIEF)-5 scores, International Prostate Symptom Score (IPSS), quality of life (QoL) scores, and postoperative complications were recorded during follow-up.

RESULTS

Overall, 19.5% of patients were low-risk, 36.4% were intermediate-risk, and 44.1% were high-risk according to the D'Amico risk classification. The median follow-up was 12.09 ± 5.85 months, and the biochemical-free survival rates for the low-, intermediate-, and high-risk groups were 100% (15/15), 96.4% (27/28), and 79.4% (27/34), respectively. Four patients (5.2%) received salvage radiotherapy and all maintained biochemical-free survival. The mean IPSS and QoL scores before versus after HIFU were 10.4 versus 6.8 (p = 0.003) and 3.2 versus 3.0 (p = 0.096), respectively. There was no statistically significant change in preoperative and postoperative IIEF scores (20.6 vs. 19; p = 0.062) in patients who had an IIEF score of >15 at baseline and received nerve-sparing procedures (subtotal ablation).

CONCLUSIONS

The results of Sonablate® HIFU in Taiwan indicated adequate short-term cancer control, excellent potency, and continence preservation. HIFU can achieve improvement of IPSS with low complication rates.

Salvage Radiotherapy Plus Androgen Deprivation Therapy for High-Risk Prostate Cancer with Biochemical Failure after High-Intensity Focused Ultrasound as Primary Treatment

We conduct a retrospective analysis of salvage radiotherapy plus androgen deprivation therapy (SRT+ADT) for high-risk prostate cancer patients with biochemical failure after high-intensity focused ultrasound (HIFU) as the primary treatment. A total of 38 patients, who met the criteria of biochemical failure and were consecutively treated with SRT+ADT, were enrolled. All patients received intensity modulated radiotherapy with a median dose of 70 Gy to the clinical target volume. ADT was given before, during or after the course of SRT with the duration of ≦6 months (n = 14), 6−12 months (n = 12) or >12 months (n = 12). The median follow-up was 45.9 months. A total of 10 (26.3%) patients had biochemical failure after SRT+ADT. The cumulative 5-year biochemical progression free survival (b-PFS) and overall survival (OS) rate was 73.0% and 80.3%, respectively. A nadir prostate-specific antigen (nPSA) value 0.02 ng/mL was observed to predict the b-PFS in multivariate analysis. The 5-year b-PFS was 81.6% for those with nPSA < 0.02 compared with 25.0% with nPSA ≧ 0.02. The adverse effects related to SRT+ADT were mild in most cases and only three (8%) patients experienced grade 3 urinary toxicities. For high-risk prostate cancer after HIFU as primary treatment with biochemical failure, our study confirms the feasibility of SRT+ADT with high b-PFS, OS and low toxicity.

Applications of Focused Ultrasound in the Treatment of Genitourinary Cancers

Simple Summary

Cancer is a prevalent disease globally, and conventional treatment options have been associated with substantial morbidity for patients. The unique acoustic properties and biological effects of focused ultrasound have been investigated for use as an alternative treatment option for various forms of cancer with lower associated morbidity than standard treatments. The objective of our review was to assess the current state and various applications of focused ultrasound for the treatment of genitourinary cancers, including prostate, kidney, bladder, penile, and testicular malignancies. Current research demonstrates that focused ultrasound-based focal therapy shows promise for the treatment of localized prostate and kidney cancer, and the effect of ultrasound on cell membranes may increase the efficacy of chemotherapeutics and radiotherapy. Focused ultrasound-based treatment modalities should continue to be investigated as an alternative or complementary treatment option for cancer patients.

Abstract

Traditional cancer treatments have been associated with substantial morbidity for patients. Focused ultrasound offers a novel modality for the treatment of various forms of cancer which may offer effective oncological control and low morbidity. We performed a review of PubMed articles assessing the current applications of focused ultrasound in the treatment of genitourinary cancers, including prostate, kidney, bladder, penile, and testicular cancer. Current research indicates that high-intensity focused ultrasound (HIFU) focal therapy offers effective short-term oncologic control of localized prostate and kidney cancer with lower associated morbidity than radical surgery. In addition, studies in mice have demonstrated that focused ultrasound treatment increases the accuracy of chemotherapeutic drug delivery, the efficacy of drug uptake, and cytotoxic effects within targeted cancer cells. Ultrasound-based therapy shows promise for the treatment of genitourinary cancers. Further research should continue to investigate focused ultrasound as an alternative cancer treatment option or as a complement to increase the efficacy of conventional treatments such as chemotherapy and radiotherapy.

Changes in quality of life and lower urinary tract symptoms over time in cancer patients after a total prostatectomy: systematic review and meta-analysis

PURPOSE

This study aimed to clarify associations between and changes over time in lower urinary tract symptoms (LUTS) and quality of life (QOL) in cancer patients after a total prostatectomy.

METHODS

The subjects were cancer patients who had undergone total prostatectomy and had participated in non-randomized controlled trials, cohort studies, or case-control studies with outcomes of changes over time in LUTS or QOL. Fourteen studies were included for systematic review and meta-analysis.

RESULTS

Compared to preoperatively, the International Prostate Symptom Score (IPSS)-a LUTS indicator-yielded the following, 3 months after operation (MD [95% confidence interval, CI] = -0.27 [-2.22 to 1.68], p = .7855), 6 months after operation (MD [95% CI] = -2.12 [-3.04 to -1.20], p < .0001), and 12 months after operation (MD [95% CI] = -2.27 [-2.63 to -1.92], p < .0001), demonstrating significant decrease and, therefore, improvement of symptoms after 6 months. International Prostate Symptom Score-Quality of Life (IPSS-QOL), a QOL indicator, was significantly reduced at 12 months after surgery, indicating improved QOL (MD [95% CI] = -0.49 [-0.87 to -0.11], p = .0107), but there was heterogeneity between different studies (I² = 89.19%). A cumulative meta-analysis showed a tendency for greater improvements in IPSS-QOL at 12 months after surgery, the older the mean age and the higher the mean pre-surgery IPSS. Factors of age, prostate volume, and pre-surgery IPSS were related to postoperative LUTS; exacerbation of both urinary incontinence and urinary tract obstruction was related to QOL.

CONCLUSION

While LUTS improves over time after total prostatectomy, it takes 6 to 12 months after surgery. As there is an association between LUTS and QOL, support to promote self-management of LUTS is important.

Significant Impact of the Anterior Transition Zone Portion Treatment on Urinary Function After Focal Therapy with High-Intensity Focused Ultrasound for Prostate Cancer

Background: There is lack of evaluation of the effect of the treated area on the urinary function after focal therapy. The objectives of the study is to evaluate the effects of focal therapy on urinary function in the anterior portion of the transition zone (TZ) with transrectal high-intensity focused ultrasound (HIFU) for localized prostate cancer (PCa). Methods: From 2016 to 2018, patients who were diagnosed as having localized PCa and treated with focal therapy with HIFU, were included prospectively. The urinary function and complications were evaluated separately in the treated regions of the anterior TZ (TZ group) and other portions (other group) for 12 months. Before and after the treatment, the International Prostate Symptom Score (IPSS), IPSS Quality Of Life (QOL), Overactive Bladder Symptom Score (OABSS), and uroflowmetry were evaluated to assess the urinary function. Results: Ninety patients were included in the study. There was no significant differences in the patients' characteristics between the two groups. At 1 month after the treatment, IPSS (p = 0.011), IPSS QOL (p = 0.002), OABSS (p = 0.002), maximum flow rates (p = 0.011), and residual urine volume (p = 0.011) in TZ group were significantly deteriorated compared with the other group. Multivariate logistic regression analysis revealed that anterior TZ treatment (odds ratio, 3.386; p = 0.029) was an independent risk factor for the deterioration with ≥32% of preoperative status of maximum flow rates. Concerning complication, the rates of Grade 2 urinary retention and Grade 3 urethral stricture were 15.4% and 11.5% in the TZ group and 0% and 0% in the other group, respectively. Conclusions: There was a greater risk of urinary dysfunction with treatment in the anterior TZ portion than in the other portion at 1 month after focal therapy with HIFU.

The primary treatment of prostate cancer with high-intensity focused ultrasound: A systematic review and meta-analysis

BACKGROUND

We systematically evaluated the evidences on oncological and functional outcomes of high-intensity focused ultrasound (HIFU) as the primary treatment for localized prostate cancer (PCa).

METHODS

A systematic review was used Medline, Embase, and the Cochrane Library from the inception of each database. The review analyzed the oncological and functional outcomes of HIFU in the treatment of PCa. The RevMan 5.3 software was used for quantity analysis incidence of complications.

RESULTS

Twenty-seven articles were included for analysis with a total of 7393 patients. Eighteen studies investigated the whole-gland HIFU, and the duration of follow-up ranged from 2 to 168 months. After whole-gland HIFU, the mean prostate-specific antigen (PSA) nadir was found to be 0.4 to 1.95 ng/mL and the mean time to PSA nadir was 2.4 to 5.4 months. The rate of positive biopsy after HIFU was 4.5% to 91.1%. Meta-analysis revealed the incidences of urinary incontinence, impotence, urinary obstruction, retention, and infection was 10%, 44%, 15%, 11%, 7%, respectively. Nine studies investigated partial-gland HIFU, and the duration of follow-up was 1 to 131 months. After partial-gland HIFU, the mean PSA nadir was 1.9 to 2.7 ng/mL and the mean time to PSA nadir 5.7 to 7.3 months. The rate of positive biopsy after HIFU in the treatment area was 14% to 37.5%. Meta-analysis revealed the incidences of urinary incontinence, impotence, urinary obstruction, retention, and infection was 2%, 21%, 2%, 9%, 11%, respectively.

CONCLUSIONS

Early evidence suggested the partial-gland HIFU was safer than whole-gland HIFU, and they had similar oncological outcomes. More prospective randomized controlled trials of whole-gland and partial-gland HIFU for PCa was needed.

Whole-gland ablation therapy versus active surveillance for low-risk prostate cancer: a prospective study

Introduction

The objective of this study is assess the outcomes of whole-gland ablation (high-intensity focused ultrasound (HIFU), cryotherapy and brachytherapy) and active surveillance (AS) in patients with low-risk prostate cancer (PCa).

Material and methods

This prospective non-randomised study included 155 patients with low-risk PCa managed with either ablative therapy or AS. Follow-up included mpMRI, biopsies, prostate-specific antigen (PSA), quality of life and complications for up to 24 months. The primary endpoint was cancer progression. The secondary endpoint was the impact of each treatment on the quality of life.

Results

Mean total preoperative PSA was 8.8 ±1.5 ng/ml. Of 155 patients, 125 received treatment: 45 – HIFU; 45 – cryoablation; 35 – brachytherapy. Thirty were under AS. Mean nadir PSA levels were 0.64 ±0.55 ng/ml for HIFU, 0.53 ±0.38 ng/ml for cryoablation and 0.48 ±0.34 ng/ml for brachytherapy. In the AS group, mean PSA was 9.9 ±3.8 ng/ml. Biochemical relapse-free survival rates at 24 months were 81.8% for HIFU, 85% for cryoablation, 93.9% for brachytherapy and 93.3% for AS. In only one HIFU patient relapse was not confirmed on biopsy. Increased anxiety was found in up to 6.7% after treatment and in 36.7% of patients undergoing AS. The Kaplan-Meier analysis revealed no statistical differences between the techniques.

Conclusions

Whole-gland ablative therapy can be considered a viable treatment modality for carefully selected patients with low-risk PCa who are reluctant to select AS due to anxiety.

Cohort study of high-intensity focused ultrasound in the treatment of localised prostate cancer treatment: Medium-term results from a single centre

We report medium-term results in men receiving primary whole-gland HIFU (WG-HIFU) and following salvage treatment. One hundred and twenty-eight patients in a single hospital were enrolled. The enrolled patients were treated with WG-HIFU for primary localized prostate cancer. Salvage treatment include androgen deprivation therapy, secondary HIFU and salvage radiation therapy. Our primary outcomes were biochemical recurrence–free survival, salvage treatment–free survival, and metastasis-free survival. Secondary outcomes included urinary incontinence, de novo erectile dysfunction, acute epididymitis, bladder neck contracture, and urethral stricture. The 5-year biochemical recurrence–free survival rates were 85.7%, 82.7%, and 45.2% for D’Amico low-, intermediate-, and high-risk groups, respectively. Multivariate analysis revealed high risk group is the only predictor of significant shorter biochemical recurrence free survival, salvage treatment free survival, and metastasis free survival. Of 38 patients receiving salvage treatment after biochemical recurrence, 29 (76.3%) became free from biochemical recurrence. Rates of the adverse events of urinary incontinence, acute epididymitis, bladder neck contracture or urethral stricture, and de novo erectile dysfunction were 2.3%, 10.9%, 20.3%, 65.6%, respectively. In conclusion, WG-HIFU is an effective treatment option for localised prostate cancer, especially in D’Amico low- and intermediate-risk cases. The success rate of salvage treatment with radiation therapy and secondary HIFU for biochemical recurrence was acceptable. Fewer adverse events were caused by HIFU, especially incontinence and erectile dysfunction, than by radical prostatectomy and radiotherapy.

Histotripsy: The Next Generation of High-Intensity Focused Ultrasound for Focal Prostate Cancer Therapy

This article reviews the most current methods and technological aspects of high-intensity focused ultrasound (HIFU), which is termed histotripsy. The rationale for focal therapy for prostate carcinoma rather than prostatectomy, which is being used extensively throughout Europe and Asia, is presented, and an argument for why HIFU is the modality of choice for primary therapy and recurrent disease is offered. The article presents a review of the technical advances including higher ultrasound beam energy than current thermal HIFU which allows for more accurate tissue targeting, less collateral tissue damage, and faster treatment times. Finally, the article presents a discussion about the advantage of ultrasound guidance for histotripsy in preference to magnetic resonance imaging guidance primarily based on cost, ease of application, and portability.

Survival and quality of life outcomes of high-intensity focused ultrasound treatment of localized prostate cancer

BACKGROUND

To evaluate the survival and quality of life (QoL) outcomes of high-intensity focused ultrasound (HIFU) whole-gland ablation for localized prostate cancer.

METHODS

Over 8 years, men with localized prostate cancer treated with whole-gland HIFU were prospectively followed. Transrectal prostate ablation was performed under general anesthesia with Sonablate-500® (Sonacare Medical©, Charlotte, North Carolina, USA). The primary outcome was failure-free survival defined as no transition to any of the following: (1) local salvage therapy (surgery or radiotherapy), (2) systemic therapy, (3) metastases, or (4) prostate cancer-specific mortality. Secondary outcomes included both survival outcomes and QoL measures.

RESULTS

Of 70 men, 29.7% had International Society of Urological Pathology (ISUP) grade 1, 43.8% ISUP 2, 10.9% ISUP 3, and 15.6% ISUP 4 disease. At median follow-up of 83.4 months, overall mortality was 8.6% and prostate cancer-specific mortality 0%. Failure-free survival was 78.2% at 5 years and 71.2% at 7 years. Of all men, 7.1% of men developed metastases, with median metastasis-free survival of 75.4 months. There was negligible post-HIFU urinary incontinence or lower urinary tract symptom with a median Male Urogenital Distress Inventory score of 32 at 6 months and 33 at 12 months and median IPSS of 4 at 6 months and 3 at 12 months. Median Radiation Therapy Oncology Group rectal toxicity score was 0 throughout. In men who had mild or no erectile dysfunction at baseline (International Index of Erectile Function ≥17), the mean International Index of Erectile Function score declined to 37% from 23.5 at baseline to 14.7 at 12 months.

CONCLUSION

At median follow-up of 7 years, whole-gland HIFU appears to have comparable survival outcomes with other cohort studies involving radical prostatectomy and radiotherapy patient. It has low impact on QoL, preserved urinary continence, and erectile function approximate to nerve-sparing prostatectomy. Whole-gland HIFU presents a potential alternative minimally invasive and safe option for the treatment of localized prostate cancer.

MR Imaging-Guided Transurethral Ultrasound Ablation of Localized Prostate Cancer: Preliminary Experience from a Single Center in a Prospective, Multi-Center, Single-Arm Clinical Trial

This report details a single-center experience of using magnetic resonance imaging-guided transurethral ultrasound ablation (TULSA) for whole-gland prostate treatment. Nine men with organ-confined low-to-intermediate-risk prostate cancer underwent the TULSA procedure. The primary endpoint of reduction of more than 75% was achieved in 8 of 9 patients, and all patients demonstrated a histologic benefit at 12-month biopsy. No major urinary or gastrointestinal side effects were observed, and there were no postprocedural changes in erectile firmness. These findings suggest that TULSA is potentially safe and efficacious for patients with low-to-intermediate-risk disease.

Radical prostatectomy versus brachytherapy for clinically localized prostate cancer on oncological and functional outcomes: a meta-analysis

Background

Prostate cancer (PCa) is a form of malignancy that harms the health status of elderly men worldwide. It is unclear which of radical prostatectomy (RP) or brachytherapy (BT) is the more effective treatment for PCa. This study presents the first highly comprehensive and up-to-date comparative analysis of the overall outcomes of RP versus BT.

Methods

We conducted a systematic literature search for studies published on PubMed, EMBASE, and the Cochrane Library on the outcomes of RP versus BT in clinically localized PCa. The cumulative analysis was performed using Review Manager Version 5.3 software, and the Chi-square test was employed to test the statistical heterogeneity. The summary odds ratio (OR) and standard mean difference (SMD) was estimated using random effects models at 95% confidence intervals (CIs).

Results

In total, 2 randomized, 2 prospective, and 21 retrospective comparative studies were included. No significant differences in biochemical recurrence rate (BCR) (OR: 1.24; 95% CI: 0.91, 1.68) and prostate cancer-specific mortality (PCSM) (OR: 1.62; 95% CI: 0.86, 3.04) between RP and BT were noted. With erectile dysfunction and urinary incontinence, BT was more protective than RP in both short-term post-operative reports (OR: 2.06; 95% CI: 1.15, 3.70 and OR: 4.62; 95% CI: 2.33, 9.16) and long-term patient outcome reports (SMD: -5.62; 95% CI: -13.81, 2.57 and SMD: -11.52; 95% CI: -18.32, -4.72).

Conclusions

BT and RP for PCa therapy pose comparable risks of PCSM and BCR, while BT is associated with a lower incidence of erectile dysfunction and urinary incontinence. This study tentatively confirms that BT is an alternative to RP for patients seeking a curative treatment with minimal risks of urinary incontinence and sexual dysfunction.

Translation of Cryobiological Techniques to Socially Economically Deprived Populations—Part 2: Cryosurgery

Cold and cryogenic temperatures are used for treating cancer and other pathological conditions in various fields of medicine. Cryosurgery, which resides at the interface of medicine and engineering, has attracted the interest of engineers, scientists, and medical doctors. Recently, particularly since the end of the 1980s, technological developments in cryotherapy equipment and enormous advances in imaging techniques, such as computed tomography and ultrasonography, have allowed surgeons and interventional radiologists to precisely guide cryogenic probes into tumors while avoiding damage to surrounding tissues. Extensive studies have allowed us to conclude that the use of cryogenics facilitates the successful treatment of solid tumors in various organs such as lung, liver, bones, kidneys, prostate, etc. Its simplicity of use, effectiveness, low cost, and limited demand on hospital infrastructure and personnel have made cryosurgery particularly suitable for the treatment of patients of socio-economically deprived populations.

The Impact of Focused Ultrasound in Two Tumor Models: Temporal Alterations in the Natural History on Tumor Microenvironment and Immune Cell Response

Image-guided focused ultrasound (FUS) has been successfully employed as an ablative treatment for solid malignancies by exposing immune cells to tumor debris/antigens, consequently inducing an immune response within the tumor microenvironment (TME). To date, immunomodulation effects of non-ablative pulsed-FUS (pFUS) on the TME are poorly understood. In this study, the temporal differences of cytokines, chemokines, and trophic factors (CCTFs) and immune cell populations induced by pFUS were interrogated in murine B16 melanoma or 4T1 breast cancer cells subcutaneously inoculated into C57BL/6 or BALB/c mice. Natural history growth characteristics during the course of 11 days showed a progressive increase in size for both tumors, and proteomic analysis revealed a shift toward an immunosuppressive TME. With respect to tumor natural growth, pFUS applied to tumors on days 1, 5, or 9 demonstrated a decrease in the growth rate 24 h post-sonication. Flow cytometry analysis of tumors, LNs, and Sp, as well as CCTF profiles, relative DNA damage, and adaptive T-cell localization within tumors, demonstrated dynamic innate and adaptive immune-modulation following pFUS in early time points of B16 tumors and in advanced 4T1 tumors. These results provide insight into the temporal dynamics in the treatment-associated TME, which could be used to evaluate an immunomodulatory approach in different tumor types.

Sexual function outcomes following interventions for prostate cancer: are contemporary reports on functional outcomes misleading?

Patients with primary localised prostate cancer (PCa) have a wide choice of curative therapeutic interventions, including active surveillance, surgical, focal and radiation therapies. Based on clinical and oncological characteristics, treatment decisions entail consideration of oncological and functional outcomes with important effects on quality of life. We aimed to highlight evidence surrounding present inconsistencies, the problems this presents to clinicians and patients alike and the rationale for using return to baseline as a more realistic and objective functional outcome measure for assessing sexual function in this particularly sensitive group of men. We performed a non-systematic literature review of numerous non-validated, arbitrary thresholds employed in evaluation of sexual function outcomes in men undergoing intervention for primary localised PCa. The literature presents much heterogeneity in measurement methods and outcome measures, which lack context and present difficulties when counselling patients to make informed, autonomous decisions. These include findings from the most widely used internationally validated tools, such as the International Index of Erectile Function (IIEF), UCLA prostate cancer index and European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core-30 (QLQ-C30). There is a need for standardisation of reporting outcomes following PCa treatment to facilitate evaluation of existing and emerging technologies.

Deep Learning for Real-time, Automatic, and Scanner-adapted Prostate (Zone) Segmentation of Transrectal Ultrasound, for Example, Magnetic Resonance Imaging-transrectal Ultrasound Fusion Prostate Biopsy

BACKGROUND

Although recent advances in multiparametric magnetic resonance imaging (MRI) led to an increase in MRI-transrectal ultrasound (TRUS) fusion prostate biopsies, these are time consuming, laborious, and costly. Introduction of deep-learning approach would improve prostate segmentation.

OBJECTIVE

To exploit deep learning to perform automatic, real-time prostate (zone) segmentation on TRUS images from different scanners.

DESIGN, SETTING, AND PARTICIPANTS

Three datasets with TRUS images were collected at different institutions, using an iU22 (Philips Healthcare, Bothell, WA, USA), a Pro Focus 2202a (BK Medical), and an Aixplorer (SuperSonic Imagine, Aix-en-Provence, France) ultrasound scanner. The datasets contained 436 images from 181 men.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Manual delineations from an expert panel were used as ground truth. The (zonal) segmentation performance was evaluated in terms of the pixel-wise accuracy, Jaccard index, and Hausdorff distance.

RESULTS AND LIMITATIONS

The developed deep-learning approach was demonstrated to significantly improve prostate segmentation compared with a conventional automated technique, reaching median accuracy of 98% (95% confidence interval 95-99%), a Jaccard index of 0.93 (0.80-0.96), and a Hausdorff distance of 3.0 (1.3-8.7) mm. Zonal segmentation yielded pixel-wise accuracy of 97% (95-99%) and 98% (96-99%) for the peripheral and transition zones, respectively. Supervised domain adaptation resulted in retainment of high performance when applied to images from different ultrasound scanners (p > 0.05). Moreover, the algorithm's assessment of its own segmentation performance showed a strong correlation with the actual segmentation performance (Pearson's correlation 0.72, p < 0.001), indicating that possible incorrect segmentations can be identified swiftly.

CONCLUSIONS

Fusion-guided prostate biopsies, targeting suspicious lesions on MRI using TRUS are increasingly performed. The requirement for (semi)manual prostate delineation places a substantial burden on clinicians. Deep learning provides a means for fast and accurate (zonal) prostate segmentation of TRUS images that translates to different scanners.

PATIENT SUMMARY

Artificial intelligence for automatic delineation of the prostate on ultrasound was shown to be reliable and applicable to different scanners. This method can, for example, be applied to speed up, and possibly improve, guided prostate biopsies using magnetic resonance imaging-transrectal ultrasound fusion.

Primary whole-gland ablation for localized prostate cancer with high-intensity focused ultrasound: The important predictors of biochemical recurrence

OBJECTIVES

To identify predictive factors of biochemical recurrence for patients undergoing high-intensity focused ultrasound treatment for localized prostate cancer.

METHODS

We retrospectively identified patients receiving whole-gland prostate ablation with high-intensity focused ultrasound for localized prostate cancer from 2009 to 2015. All the patients received pre-high-intensity focused ultrasound radical transurethral resection of the prostate. We included perioperative parameters as follows: age, preoperative prostate volume, stage of operation, initial prostate-specific antigen, T stage, postoperative prostate-specific antigen nadir, Gleason score, time to prostate-specific antigen nadir and the presence of prostate-specific antigen biochemical recurrence. Multivariable Cox regression and Kaplan-Meier analysis were used for investigating predictors of recurrence, and receiver operating characteristic analysis was used for the cut-off values of prostate-specific antigen nadir.

RESULTS

Among 182 patients, 26.9% had prostate-specific antigen biochemical recurrence after high-intensity focused ultrasound during the median follow-up period of 32.21 months. Gleason score ≥7 (Gleason score 7, hazard ratio 2.877, P = 0.027), stage ≥T2b (T2b, hazard ratio 3.16, P = 0.027) and prostate-specific antigen nadir (hazard ratio 1.11, P < 0.001) were statistically significant, whereas there was no significance in prostate volume and initial prostate-specific antigen. We posit that a cut-off level of prostate-specific antigen nadir 0.43 ng/mL might be considered as an independent predictive factor for prostate-specific antigen biochemical recurrence in high-intensity focused ultrasound patients in multivariate analysis (P < 0.001, hazard ratio 7.39, 95% confidence interval 3.56-15.37), and created a new nadir-related prediction model for biochemical recurrence prediction.

CONCLUSIONS

Postoperative prostate-specific antigen nadir of 0.43 ng/mL can be considered an important predictive factor for biochemical recurrence in primary whole-prostate gland high-intensity focused ultrasound treatment, and the nadir-related prediction model might provide a reference for early salvage treatment. Furthermore, Gleason score ≥7, stage ≥T2b might be associated with unfavorable outcomes, although prostate volume and higher initial prostate-specific antigen appear not to be associated with biochemical recurrence for the high-intensity focused ultrasound treatment.

Focused ultrasound: tumour ablation and its potential to enhance immunological therapy to cancer

Various kinds of image-guided techniques have been successfully applied in the last years for the treatment of tumours, as alternative to surgical resection. High intensity focused ultrasound (HIFU) is a novel, totally non-invasive, image-guided technique that allows for achieving tissue destruction with the application of focused ultrasound at high intensity. This technique has been successfully applied for the treatment of a large variety of diseases, including oncological and non-oncological diseases. One of the most fascinating aspects of image-guided ablations, and particularly of HIFU, is the reported possibility of determining a sort of stimulation of the immune system, with an unexpected "systemic" response to treatments designed to be "local". In the present article the mechanisms of action of HIFU are described, and the main clinical applications of this technique are reported, with a particular focus on the immune-stimulation process that might originate from tumour ablations.