Current Status of HIFU and Cryotherapy in Prostate Cancer – A Review

Integrating intratumoral and peritumoral radiomics with clinical risk factors for prognostic prediction in pancreatic ductal adenocarcinoma patients undergoing combined chemotherapy and HIFU ablation

OBJECTIVE

A radiomics nomogram will be created utilizing MRI data from intratumoral and peritumoral areas to forecast survival outcomes in patients who have had treatment for pancreatic ductal adenocarcinoma (PDAC).

METHODS

A total of 87 individuals diagnosed with PDAC were included in the study, with 60 patients in the training cohort and 27 patients in the validation cohort. A grand total of 2395 radiomics characteristics were extracted from the tumor region and the peritumoral region. The least absolute shrinkage and selection operator (LASSO) method was used to select features and create a radiomics score, also known as the Rad-score. A multivariate regression analysis was then conducted to build the radiomics nomogram. The evaluation of the nomogram included discrimination, calibration, and clinical utility assessments.

RESULTS

Based on the conclusions derived from the multivariate Cox model, Rad-Score, jaundice, and tumor size were identified as independent risk factors for overall survival (OS). The inclusion of the Rad-score in the radiomics nomogram led to improved accuracy in predicting survival compared to the clinical model. Patients were categorized into high-risk and low-risk groups based on their Rad-Score. Kaplan-Meier analysis revealed a statistically significant difference between the two groups (p < 0.05). Furthermore, the radiomics nomogram demonstrated excellent ability to differentiate, calibrate, and provide clinical utility in both the training and validation groups.

CONCLUSIONS

The MRI-based intratumoral and peritumoral radiomics nomogram, integrating the Rad-score and clinical data, provided better prognostic prediction for PDAC patients after HIFU treatment, which may hold great potential for guiding personalized care for these patients.

Model based deep learning method for focused ultrasound pathway scanning

The primary purpose of high-intensity focused ultrasound (HIFU), a non-invasive medical therapy, is to precisely target and ablate tumors by focusing high-frequency ultrasound from an external power source. A series of ablations must be performed in order to treat a big volume of tumors, as a single ablation can only remove a small amount of tissue. To maximize therapeutic efficacy while minimizing adverse side effects such as skin burns, preoperative treatment planning is essential in determining the focal site and sonication duration for each ablation. Here, we introduce a machine learning-based approach for designing HIFU treatment plans, which makes use of a map of the material characteristics unique to a patient alongside an accurate thermal simulation. A numerical model was employed to solve the governing equations of HIFU process and to simulate the HIFU absorption mechanism, including ensuing heat transfer process and the temperature rise during the sonication period. To validate the accuracy of this numerical model, a series of tests was conducted using ex vivo bovine liver. The findings indicate that the developed models properly represent the considerable variances observed in tumor geometrical shapes and proficiently generate well-defined closed treated regions based on imaging data. The proposed strategy facilitated the formulation of high-quality treatment plans, with an average tissue over- or under-treatment rate of less than 0.06%. The efficacy of the numerical model in accurately predicting the heating process of HIFU, when combined with machine learning techniques, was validated through quantitative comparison with experimental data. The proposed approach in cooperation with HIFU simulation holds the potential to enhance presurgical HIFU plan.

Optical Property Measurement and Temperature Monitoring in High-Intensity Focused Ultrasound Therapy by Diffuse Optical Tomography: A Correlation Study

In this article, we propose a new approach utilizing diffuse optical tomography (DOT) to monitoring the changes in tissues’ optical properties and temperature in high-intensity focused ultrasound (HIFU) therapy. By correlating the tissue reduced scattering coefficient (μs’) reconstructed by DOT and the temperature measured by a thermocouple, the quantitative relationship between μs’ and temperature in HIFU treatment was explored. The experiments were conducted using porcine and chicken breast muscle tissues during HIFU; the temperature of each tissue sample was recorded using a thermocouple. To incorporate the temperature dependency of tissue optical properties, both polynomial and exponential models were utilized to fit the experimental data. The results show that the change of μs’ during HIFU treatment could be detected in real-time using DOT and that this change of μs’ is quantitatively correlated with tissue temperature. Furthermore, while the tissue-type-dependent relationship between μs’ and temperature is non-linear in nature, it is stable and repeatable. Therefore, our approach has the potential to be used to predict temperature of tissue during HIFU treatment.

Prevalence and outcomes of focal ablation versus prostatectomy for elderly patients with prostate cancer: a population-based study

Background

Despite rapid advances in the treatment of prostate cancer (PCa), the optimal treatment for elderly patients with PCa remains unclear due to a lack of high-quality evidence. This study aimed to evaluate whether surgical procedures are beneficial for PCa patients aged 75 years and older and compare the effects of focal ablation and prostatectomy.

Methods

Male patients aged 75 years and older who were diagnosed with Tis-T2/N0/M0 PCa between 2000 and 2017 were retrospectively identified from the Surveillance, Epidemiology, and End Results program database. Cox regression models were used to test for statistical differences between the overall survival (OS) and disease-specific survival (DSS).

Results

A total of 114,506 patients aged 75 years and older with PCa were included in this study, among which 60,131 died during the study period. The most prevalent surgical procedure for these patients was focal ablation. The local excision rate increased with advancing age, while the prostatectomy rate decreased sharply with age. The proportion of the elderly patients who underwent a focal ablation also increased with the age at diagnosis. The survival rate of patients aged 75 years and older who underwent a focal ablation was significantly worse than that for those who did not undergo any surgical procedures (OS: HR, 1.32, P<0.001; DSS: HR, 1.58, P<0.001). Although only a few of the patients underwent prostatectomy, the procedure was still related to improved OS and DSS (OS: HR, 0.60, P< 0.001; DSS: HR, 0.37, P<0.001) rates.

Conclusions

Focal ablation has gradually replaced prostatectomy as the most common surgical procedure for elderly patients with PCa in the United States. However, our results revealed that the procedure might not provide benefits for elderly patients with PCa; instead, we found that focal ablation resulted in increased negative effects on patient prognoses. Elderly patients should have the same opportunity to be treated with standard surgical interventions as younger patients.

A Clinical Prototype Transrectal Diffuse Optical Tomography (TRDOT) System for In vivo Monitoring of Photothermal Therapy (PTT) of Focal Prostate Cancer

We describe the rationale, design, fabrication and performance of a clinical transrectal diffuse optical tomography (TRDOT) system for in vivo monitoring of photothermal therapy (PTT) of localized prostate cancer. The system comprises a 32-channel fiberoptic-based, MRI-compatible transrectal probe connected to a computer-controlled instrument that includes laser diode sources, an optical fiber switch and photomultiplier tube detectors. Performance tests were performed in tissue-simulating phantoms and in ex vivo muscle tissue during PTT treatment. The safety and technical feasibility of in vivo transrectal use were tested in a canine prostate model and in a first-in-human study in a patient before PTT treatment. Limitations of the system are discussed, as well as further developments to translate it into planned clinical trials for monitoring the photocoagulation boundary in the prostate during PTT.

Optimization of prostatic cryosurgery with multi-cryoprobe based on refrigerant flow

Cryosurgery is a promising novel minimally invasive surgical technique to eradicate carcinoma and non-carcinoma tissues by freezing. In this research, we applied a transient 3D two-phase refrigerant flow model inside the LN₂ boiling chamber as well as a bioheat transfer model inside the tissues to evaluate the optimized ablation outcome during prostatic cryosurgery. For the evaluation of the scenarios, a defect function was used that considers non-ablated target tissue (prostate/cancer tissue) as well as ablated healthy tissue, in which the ablated tissue was evaluated using a temperature threshold. Three different configurations using three LN₂ cryoprobes were analyzed during the modeling study, and the best configuration with the three LN₂ cryoprobes positioned isoscelesly was found. For this configuration, temperature distributions and temperature profiles at specific points within the tissue were investigated numerically. Owing to its low computational cost, the 3D coupled model has an advantage in accurate modeling cryosurgery for curing numerous diseases.

Urological technology: where will we be in 20 years' time?

Since prehistoric times, our understanding of urology has rapidly expanded. Whilst primitive urologists began by using urine as a therapeutic substance, modern urologists may find themselves removing a kidney remotely by driving a robotic arm, with seven degrees of movement, while using image overlay-augmented reality. This review provides an insight into the potential status of urological technology in 20 years' time, assessed through an analysis of developments in imaging, diagnostics, robotics and further technologies. A particular emphasis is given to the promising fields of minimally invasive techniques, nanotechnology and tissue engineering, which likely hold the key to a new era for urology.

Recurrence of prostate cancer after HIFU. Proposal of a novel predictive index

Background and aim of the work: Prostate cancer is one of the most common cancers in men over 50 years of age. Surgery, radiotherapy and hormonal manipulation represent its typical treatment. High-Intensity Focused Ultrasound (HIFU) is an alternative choice in localized prostate cancer. To date, an index for prediction of recurrence in patients treated with HIFU is not availabe. Our study proposes a novel index for the predition of recurrence able to determine if a candidate is fit for this tratment. methods: 107 patients underwent HIFU fram 2010 to 2015. A total of 12 variables were considered for the analysis. The final predictive model was obtained through a stepwise forward selection method. Results: The final model used a total of 6 variables, all correlated to the response variable. The Index is able to predict the recurrence after HIFU tratment in the most majority of candidates to treatment. The index may be used to make a more scientific decision with regard to choosing optimal candidates for HIFU. (www.actabiomedica.it)

Methods for the evaluation of biomarkers in patients with kidney and liver diseases: multicentre research programme including ELUCIDATE RCT

Background

Protein biomarkers with associations with the activity and outcomes of diseases are being identified by modern proteomic technologies. They may be simple, accessible, cheap and safe tests that can inform diagnosis, prognosis, treatment selection, monitoring of disease activity and therapy and may substitute for complex, invasive and expensive tests. However, their potential is not yet being realised.

Design and methods

The study consisted of three workstreams to create a framework for research: workstream 1, methodology – to define current practice and explore methodology innovations for biomarkers for monitoring disease; workstream 2, clinical translation – to create a framework of research practice, high-quality samples and related clinical data to evaluate the validity and clinical utility of protein biomarkers; and workstream 3, the ELF to Uncover Cirrhosis as an Indication for Diagnosis and Action for Treatable Event (ELUCIDATE) randomised controlled trial (RCT) – an exemplar RCT of an established test, the ADVIA Centaur® Enhanced Liver Fibrosis (ELF) test (Siemens Healthcare Diagnostics Ltd, Camberley, UK) [consisting of a panel of three markers – (1) serum hyaluronic acid, (2) amino-terminal propeptide of type III procollagen and (3) tissue inhibitor of metalloproteinase 1], for liver cirrhosis to determine its impact on diagnostic timing and the management of cirrhosis and the process of care and improving outcomes.

Results

The methodology workstream evaluated the quality of recommendations for using prostate-specific antigen to monitor patients, systematically reviewed RCTs of monitoring strategies and reviewed the monitoring biomarker literature and how monitoring can have an impact on outcomes. Simulation studies were conducted to evaluate monitoring and improve the merits of health care. The monitoring biomarker literature is modest and robust conclusions are infrequent. We recommend improvements in research practice. Patients strongly endorsed the need for robust and conclusive research in this area. The clinical translation workstream focused on analytical and clinical validity. Cohorts were established for renal cell carcinoma (RCC) and renal transplantation (RT), with samples and patient data from multiple centres, as a rapid-access resource to evaluate the validity of biomarkers. Candidate biomarkers for RCC and RT were identified from the literature and their quality was evaluated and selected biomarkers were prioritised. The duration of follow-up was a limitation but biomarkers were identified that may be taken forward for clinical utility. In the third workstream, the ELUCIDATE trial registered 1303 patients and randomised 878 patients out of a target of 1000. The trial started late and recruited slowly initially but ultimately recruited with good statistical power to answer the key questions. ELF monitoring altered the patient process of care and may show benefits from the early introduction of interventions with further follow-up. The ELUCIDATE trial was an ‘exemplar’ trial that has demonstrated the challenges of evaluating biomarker strategies in ‘end-to-end’ RCTs and will inform future study designs.

Conclusions

The limitations in the programme were principally that, during the collection and curation of the cohorts of patients with RCC and RT, the pace of discovery of new biomarkers in commercial and non-commercial research was slower than anticipated and so conclusive evaluations using the cohorts are few; however, access to the cohorts will be sustained for future new biomarkers. The ELUCIDATE trial was slow to start and recruit to, with a late surge of recruitment, and so final conclusions about the impact of the ELF test on long-term outcomes await further follow-up. The findings from the three workstreams were used to synthesise a strategy and framework for future biomarker evaluations incorporating innovations in study design, health economics and health informatics.

Trial registration

Current Controlled Trials ISRCTN74815110, UKCRN ID 9954 and UKCRN ID 11930.

Funding

This project was funded by the NIHR Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 6, No. 3. See the NIHR Journals Library website for further project information.

Construction of Silica-Based Micro/Nanoplatforms for Ultrasound Theranostic Biomedicine

Ultrasound (US)-based biomedicine has been extensively explored for its applications in both diagnostic imaging and disease therapy. The fast development of theranostic nanomedicine significantly promotes the development of US-based biomedicine. This progress report summarizes and discusses the recent developments of rational design and fabrication of silica-based micro/nanoparticles for versatile US-based biomedical applications. The synthetic strategies and surface-engineering approaches of silica-based micro/nanoparticles are initially discussed, followed by detailed introduction on their US-based theranostic applications. They have been extensively explored in contrast-enhanced US imaging, US-based multi-modality imaging, synergistic high-intensity focused US (HIFU) ablation, sonosensitizer-enhanced sonodynamic therapy (SDT), as well as US-triggered chemotherapy. Their biological effects and biosafety have been briefly discussed to guarantee further clinical translation. Based on the high biocompatibility, versatile composition/structure and high performance in US-based theranostic biomedicine, these silica-based theranostic agents are expected to pave a new way for achieving efficient US-based theranostics of disease by taking the specific advantages of material science, nanotechnology and US-based biomedicine.

In vivo photoacoustics and high frequency ultrasound imaging of mechanical high intensity focused ultrasound (HIFU) ablation

The thermal effect of high intensity focused ultrasound (HIFU) has been clinically exploited over a decade, while the mechanical HIFU is still largely confined to laboratory investigations. This is in part due to the lack of adequate imaging techniques to better understand the in-vivo pathological and immunological effects caused by the mechanical treatment. In this work, we explore the use of high frequency ultrasound (US) and photoacoustics (PA) as a potential tool to evaluate the effect of mechanical ablation in-vivo, e.g. boiling histotripsy. Two mice bearing a neuroblastoma tumor in the right leg were ablated using an MRI-HIFU system conceived for small animals and monitored using MRI thermometry. High frequency US and PA imaging were performed before and after the HIFU treatment. Afterwards, the tumor was resected for further assessment and evaluation of the ablated region using histopathology. High frequency US imaging revealed the presence of liquefied regions in the treated area together with fragmentized tissue which appeared with different reflecting proprieties compared to the surrounding tissue. Photoacoustic imaging on the other hand revealed the presence of deoxygenated blood within the tumor after the ablation due to the destruction of blood vessel network while color Doppler imaging confirmed the blood vessel network destruction within the tumor. The treated area and the presence of red blood cells detected by photoacoustics were further confirmed by the histopathology. This feasibility study demonstrates the potential of high frequency US and PA approach for assessing in-vivo the effect of mechanical HIFU tumor ablation.

Materials Chemistry of Nanoultrasonic Biomedicine

As a special cross-disciplinary research frontier, nanoultrasonic biomedicine refers to the design and synthesis of nanomaterials to solve some critical issues of ultrasound (US)-based biomedicine. The concept of nanoultrasonic biomedicine can also overcome the drawbacks of traditional microbubbles and promote the generation of novel US-based contrast agents or synergistic agents for US theranostics. Here, we discuss the recent developments of material chemistry in advancing the nanoultrasonic biomedicine for diverse US-based bio-applications. We initially introduce the design principles of novel nanoplatforms for serving the nanoultrasonic biomedicine, from the viewpoint of synthetic material chemistry. Based on these principles and diverse US-based bio-application backgrounds, the representative proof-of-concept paradigms on this topic are clarified in detail, including nanodroplet vaporization for intelligent/responsive US imaging, multifunctional nano-contrast agents for US-based multi-modality imaging, activatable synergistic agents for US-based therapy, US-triggered on-demand drug releasing, US-enhanced gene transfection, US-based synergistic therapy on combating the cancer and potential toxicity issue of screening various nanosystems suitable for nanoultrasonic biomedicine. It is highly expected that this novel nanoultrasonic biomedicine and corresponding high performance in US imaging and therapy can significantly promote the generation of new sub-discipline of US-based biomedicine by rationally integrating material chemistry and theranostic nanomedicine with clinical US-based biomedicine.

Diagnostic and Therapeutic Strategies for Prostate Cancer

Prostate cancer (PC) is a major disease that affects men's health worldwide. It is the second most common form of cancer in men, surpassed only by nonmelanoma skin cancers such as basal and squamous cell carcinomas. Diagnostic strategies with population screening for prostate cancer using prostate-specific antigen (PSA) has been surrounded with controversy and debated intensively ever since the PSA protein was first purified in 1979 by Wang et al. At the same time, advances in diagnostic imaging, surgery, radiation, and chemotherapy have increased the opportunity to effectively diagnose, treat, and manage PC. Given the sheer burden of PC disease in Denmark and worldwide, new and innovative strategies for cancer diagnosis and care are needed. This article is a short review of current diagnostic and therapeutic strategies for the care and management of prostate cancer in Denmark.

Post-treated prostate cancer: normal findings and signs of local relapse on multiparametric magnetic resonance imaging

The use of multiparametric magnetic resonance imaging (mp-MRI) for prostate cancer has increased over recent years, mainly for detection, staging, and active surveillance. However, suspicion of recurrence in the set of biochemical failure is becoming a significant reason for clinicians to request mp-MRI. Radiologists should be able to recognize the normal post-treatment MRI findings. Fibrosis and atrophic remnant seminal vesicles after prostatectomy are often found and must be differentiated from local relapse. Moreover, brachytherapy, external beam radiotherapy, cryosurgery, and hormonal therapy tend to diffusely decrease the signal intensity of the peripheral zone on T2-weighted images (T2WI) due to the loss of water content, consequently mimicking tumor and hemorrhage. The combination of T2WI and functional studies like diffusion-weighted imaging and dynamic contrast-enhanced improves the identification of local relapse. Tumor recurrence tends to restrict on diffusion images and avidly enhances after contrast administration either within or outside the gland. The authors provide a pictorial review of the normal findings and the signs of local tumor relapse after radical prostatectomy, external beam radiotherapy, brachytherapy, cryosurgery, and hormonal therapy.

[Comparative oncologic and functional outcomes of prostate cancer surgery with other curative treatments]

OBJECTIVE

Review of the comparative results of different treatment strategies (surgery, radiotherapy, ultrasound, surveillance) of prostate cancer, in which the main goal is the local control and the second target is the tolerance of the side effects of those treatments.

MATERIALS AND METHODS

Review of literature using Medline databases selected based on scientific relevance. Clinical keys centered on the oncological and functional outcomes of comparative series between different curative treatments.

RESULTS

The numerous comparative series between surgery and other therapeutic modalities are essentially retrospective with significant methodological bias that is difficult to overcome in order to formulate the optimal thesis. However, there is a clear tendency toward surgery usually with young patients who have intermediate risk tumors without important comorbidity.

CONCLUSION

In the absence of randomized comparative series with significant power, the oncological and functional results of the radical prostatectomy with or without adjuvant treatment seem at least the same, in a selected population of patients, compared with the combination of radiotherapy-hormonotherapy in terms of survival, without biochemical recurrence, disease-specific survival and overall survival, for the aggressive tumors necessitating curative local treatments.

Radical prostatectomy specimens - a voice against focal therapy

Introduction

The main treatment methods of prostate carcinoma are surgery and radiation therapy, both having serious side effects. Because of these side effects, the idea of organ preserving therapy emerged. Rationale to perform focal therapy is to preserve the prostate gland, along with potency and continence, offering good cancer control with appropriate treatment. The idea of gland sparing therapy is quite controversial. Presently, EAU Guidelines propose focal therapy as experimental in the treatment of prostate carcinoma.

Material and methods

The aim of the study was to asses how many patients could be qualified for focal therapy, according to post prostatectomy pathological findings. 720 patients suspected of prostate cancer were biopsied. In 324 patients, prostate carcinoma was revealed, of which 81 were subjected to radical prostatectomy. Pre and post–operative pathological results were analyzed, according to possible qualification for focal treatment.

Results

According to the clinical evaluation of all the patients referred to the treatment, 25% could be assumed to have unifocal disease and could be qualified to the focal treatment. Post–operative evaluation revealed pT2b cancer in 5%, pT2c disease in 65%, and pT3a–pT4a disease in 20% of these patients. Cancer was unilateral (pT2a–b) in only 15% of cases, and was suitable for focal treatment (small disease not extending to whole lobe– pT2a disease) in only 10%.

Conclusions

It seems that with the use of current methods, proper T–staging of the disease and amount of neoplasmatic tissue inside the gland can not be reached with great certainty. In our opinion, focal therapy should not be used in patients with ≤pT2b and high risk disease. For them, radical treatment (surgery or radiation therapy) should be recommended. For the rest of the patients, with low risk disease, keeping in mind the large scale of possible overtreatment, active surveillance is a valid treatment option. Focal therapy can be an interesting therapeutic proposition for a small group of patients with pT2a cancer, but it is not possible to select them with big certainty with current methods of imaging medicine.

Focal therapy in prostate cancer: the current situation

Prostate cancer is one of the most significant pathologies in the field of urology. The adoption of screening strategies and improvements in biopsies have resulted in an increase in early-stage tumour detection.

Radical global therapies provide very good oncological results in localised prostate cancer. However, excess treatment in low- and, in some cases, intermediate-risk groups affects the quality of life of these patients.

In the case of localised prostate cancer, focal therapies offer a minimally invasive option with good results with respect to established treatments. Although this is currently not a standard treatment, it represents the therapeutic approach with the greatest potential.

This literature review has the following objectives: to define selection criteria for patients who are candidates for focal therapy, to assess the current situation and results of the different therapeutic options, and to define procedures in cases of recurrence and for follow-ups.

We concluded that focal therapy is a viable therapeutic alternative for localised prostate cancer, specifically cryosurgery and high-intensity targeted ultrasound, which have acceptable oncologic results and a lower comorbidity compared with global treatments. Studies with a high level of scientific evidence are still needed to validate these results.

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.

Focal salvage therapy for locally recurrent prostate cancer: a review

Objectives: To evaluate the current status of focal therapy as the salvage treatment option for patients with recurrent prostate cancer after established therapy (radiation, surgery) failure for localized tumor.
Methods: A MedLine search using specified search terms was done on December 23, 2011. This research rendered 346 papers related to High-Intensity Focused Ultrasound (HIFU), 644 papers related to cryosurgery, 180 related to photodynamic therapy and 3 articles related to radio frequency ablation. Very few of these papers presented original outcome data and are included in the present review.
Results: No controlled trial was available for analysis. 
Conclusions: Salvage HIFU in patients with local recurrence of prostate cancer after radical EBRT indicate is a reasonable treatment option, but better patient selection criteria are needed. It is a promising treatment option for local recurrence after radiation therapy, with morbidity comparable with other forms of salvage treatment. The side effects are not negligible but comparable with other forms of salvage treatment. Photodynamic therapy is a new option that could be suitable for organ-confined PC recurrence after radiotherapy, but the data are very few.

Methods for characterizing convective cryoprobe heat transfer in ultrasound gel phantoms

While cryosurgery has proven capable in treating of a variety of conditions, it has met with some resistance among physicians, in part due to shortcomings in the ability to predict treatment outcomes. Here we attempt to address several key issues related to predictive modeling by demonstrating methods for accurately characterizing heat transfer from cryoprobes, report temperature dependent thermal properties for ultrasound gel (a convenient tissue phantom) down to cryogenic temperatures, and demonstrate the ability of convective exchange heat transfer boundary conditions to accurately describe freezing in the case of single and multiple interacting cryoprobe(s). Temperature dependent changes in the specific heat and thermal conductivity for ultrasound gel are reported down to -150 °C for the first time here and these data were used to accurately describe freezing in ultrasound gel in subsequent modeling. Freezing around a single and two interacting cryoprobe(s) was characterized in the ultrasound gel phantom by mapping the temperature in and around the "iceball" with carefully placed thermocouple arrays. These experimental data were fit with finite-element modeling in COMSOL Multiphysics, which was used to investigate the sensitivity and effectiveness of convective boundary conditions in describing heat transfer from the cryoprobes. Heat transfer at the probe tip was described in terms of a convective coefficient and the cryogen temperature. While model accuracy depended strongly on spatial (i.e., along the exchange surface) variation in the convective coefficient, it was much less sensitive to spatial and transient variations in the cryogen temperature parameter. The optimized fit, convective exchange conditions for the single-probe case also provided close agreement with the experimental data for the case of two interacting cryoprobes, suggesting that this basic characterization and modeling approach can be extended to accurately describe more complicated, multiprobe freezing geometries. Accurately characterizing cryoprobe behavior in phantoms requires detailed knowledge of the freezing medium's properties throughout the range of expected temperatures and an appropriate description of the heat transfer across the probe's exchange surfaces. Here we demonstrate that convective exchange boundary conditions provide an accurate and versatile description of heat transfer from cryoprobes, offering potential advantages over the traditional constant surface heat flux and constant surface temperature descriptions. In addition, although this study was conducted on Joule-Thomson type cryoprobes, the general methodologies should extend to any probe that is based on convective exchange with a cryogenic fluid.

The role of prostate-specific antigen in light of new scientific evidence

OBJECTIVE

Review the scientific evidence acquired in recent years on Prostate-Specific Antigen (PSA).

ACQUISITION OF EVIDENCE

Analysis of the available evidence on the current role of PSA, according to a panel of experts who recorded their experience on the subject.

SUMMARY OF THE EVIDENCE

Currently, PSA cannot be considered solely an indicator of the presence or absence of prostate cancer. Rather, the determination of PSA assists the urologist in indicating the most appropriate treatment for a patient with benign prostatic hypertrophic (BPH), as well as in suspecting a prostatic tumour when the PSA reading increases >0,3 ng/ml, in patients treated with 5-alpha-reductase inhibitor, over the reading achieved at six months of having initiated this treatment. Moreover, PSA is a key factor in the follow-up of patients with prostate adenocarcinoma who undergo surgery, radiation therapy or minimally invasive techniques. PSA helps to define biochemical recurrence, suggest the existence of a local or distal recurrence and propose or rule out adjuvant therapies.

CONCLUSIONS

New data on the current role of PSA in the management of patients treated for BPH and/or prostate cancer should be taken into account.

HIFU for palliative treatment of pancreatic cancer

High intensity focused ultrasound (HIFU) is a novel non-invasive modality for ablation of various solid tumors including uterine fibroids, prostate cancer, hepatic, renal, breast and pancreatic tumors. HIFU therapy utilizes mechanical energy in the form of a powerful ultrasound wave that is focused inside the body to induce thermal and/or mechanical effects in tissue. Multiple preclinical and non-randomized clinical trials have been performed to evaluate the safety and efficacy of HIFU for palliative treatment of pancreatic tumors. Substantial tumor-related pain reduction was achieved in most cases after HIFU treatment, and no significant side-effects were observed. This review provides a description of different physical mechanisms underlying HIFU therapy, summarizes the clinical experience obtained to date in HIFU treatment of pancreatic tumors, and discusses the challenges, limitations and new approaches in this modality.

Temperature dependence of the optoacoustic transformation efficiency in ex vivo tissues for application in monitoring thermal therapies

The calibration dependencies of the optoacoustic (OA) transformation efficiency on tissue temperature are obtained for the application in OA temperature monitoring during thermal therapies. Accurate measurement of the OA signal amplitude versus temperature is performed in different ex vivo tissues in the temperature range 25°C to 80°C. The investigated tissues were selected to represent different structural components: chicken breast (skeletal muscle), porcine lard (fatty tissue), and porcine liver (richly perfused tissue). Backward mode of the OA signal detection and a narrow probe laser beam were used in the experiments to avoid the influence of changes in light scattering with tissue coagulation on the OA signal amplitude. Measurements were performed in heating and cooling regimes. Characteristic behavior of the OA signal amplitude temperature dependences in different temperature ranges were described in terms of changes in different structural components of the tissue samples. The accuracy of temperature reconstruction from the obtained calibration dependencies for the investigated tissue types is evaluated.

Imaging techniques for local recurrence of prostate cancer: for whom, why and how?

Since there are salvage solutions, it is important to detect local recurrence of prostate cancer as early as possible. The first sign is "biochemical failure" in that the prostate specific antigen (PSA) concentration rises again. The definition of biochemical failure varies depending on the initial treatment: PSA greater than 0.2ng/mL after prostatectomy, nadir+2ng/mL after radiotherapy. There is no standardised definition of biochemical failure after cryotherapy, focused ultrasound, or brachytherapy. Magnetic resonance imaging (MRI) (particularly dynamic MRI) can detect local recurrence with good sensitivity. The role of spectroscopy is still under discussion. For the moment, ultrasound techniques are less effective than MRI.

Utility of immunohistochemistry markers in the interpretation of post-high-intensive focussed ultrasound prostate biopsy cores

PURPOSE

To overcome the difficulties in the interpretation of postoperative tumor obtaining biopsy cores for patients who treated their prostate cancer with high-intensity focussed ultrasound (HIFU) therapy.

METHODS

The H&E slides of 58 patients with residual prostate cancer after HIFU treatment were systematically reviewed. Correlation between the pathologist's findings and immunohistochemical expression of MIB-1, alpha-Methyl-Co-Racemase and 34βE-12 staining was analyzed.

RESULTS

Mean time from treatment to biopsy was 40.2 (8-208) weeks. The expert review of the H&E slides identified 40 patients with viable carcinoma in the post-HIFU biopsy cores. 18 patients were revised to necrosis-only-tumors. These biopsies were performed not later than 16 weeks after HIFU treatment (median 10.9 weeks, range 8-14). Both MIB-1 and AMACR staining displayed significant differential expression in viable carcinoma (p < 0.001) compared to necrosis tumors. Referring to viable carcinoma tissue, AMACR staining index was significantly rising, the longer treatment dated back from biopsy (p < 0.002). In this context, 34-β-E12 stained negative through all tumor areas and positive in the majority (85%) of the surrounding non-neoplastic epithelium.

CONCLUSIONS

AMACR and MIB-1 reliably differentiate viable carcinoma from a process of ongoing irreversible necrosis in early post-HIFU prostate biopsy cores and therefore proposed-in addition with 34 beta-E12-as useful markers exposing suspicious tumor foci in difficult cases.

Continence rate and oncological feasibility after total transurethral resection of the prostate as an alternative therapy for the treatment of prostate cancer: a pilot study

PURPOSE

The value of total transurethral resection of prostate cancer (TURPC) as an alternative therapy was first recognized by Hans J. Reuter. Thus, we conducted the study of prospectively collected data to verify total TURPC as an alternative therapy forlocalized prostate cancer.

METHODS

From January 2008 to July 2011, 14 patients with a mean age of 76.1 years (range, 66 to 89 years) with clinically localized prostate cancer were treated by prostatic resection by the corresponding author with curative intention.

RESULTS

The mean duration of TURPC was 51.7 minutes (range, 30 to 120 minutes) and the mean amount of prostatic tissue resected was 21.2 g (range, 5 to 66 g). An intra- and/or postoperative blood transfusion was necessary in 2 cases. Hyponatremia was found in 7 patients. Six months after TURPC, 3 cases of grade 1 and 1 case of grade 2 incontinence were observed. Three patients in the high-risk group did not achieve a prostate specific antigen (PSA) nadir of ≤0.2 ng/mL. PSA recurrence occurred in one case in our series. Newly developed lymph node or distant metastases were not observed during the follow-up period.

CONCLUSIONS

According to our results, transurethral resection for prostate cancer can be performed with reasonable oncological results. The PSA nadir levels, and rates of biochemical failure and postoperative complications, including incontinence, were comparable with the published results for other procedures. TURPC is also inexpensive and non-invasive, and requires short hospitalization and a short surgical time without vesicourethral anastomosis.

Follow-up of high-intensity focused ultrasound treatment for patients with hepatocellular carcinoma

Nonsurgical therapies have become treatment options for hepatocellular carcinoma (HCC). This study was to evaluate the efficacy and complications of high-intensity focused ultrasound (HIFU) treatment for patients with HCC. Between May 2001 and May 2005, 145 patients with HCC were enrolled for treatments using a HIFU tumor therapeutic system. Clinical symptoms, hepatic functions and values of serum α-fetoprotein (AFP) were tested before and after HIFU treatment. The changes in computerized tomography (CT) and magnetic resonance imaging (MRI), complications and survival time after HIFU were also obtained for further analysis. Symptoms improved or pain was relieved in 84.8% of the 145 patients and the rate of serum AFP decrease was 71.7%. The size of the target tumor shrank by various degrees. The 2-year survival rate was 80% in patients with stage Ib HCC, 51.4% in stage IIa and 46.5% in stage IIIa. During HIFU treatment, complications included body temperature increase and abnormal cardiac rhythm. After HIFU procedures, there were skin burns of different grades. In conclusion, HIFU is safe and effective for patients with hepatocellular carcinoma; HIFU can improve the survival quality of patients with HCC.

Modelling prostate motion for data fusion during image-guided interventions

There is growing clinical demand for image registration techniques that allow multimodal data fusion for accurate targeting of needle biopsy and ablative prostate cancer treatments. However, during procedures where transrectal ultrasound (TRUS) guidance is used, substantial gland deformation can occur due to TRUS probe pressure. In this paper, the ability of a statistical shape/motion model, trained using finite element simulations, to predict and compensate for this source of motion is investigated. Three-dimensional ultrasound images acquired on five patient prostates, before and after TRUS-probe-induced deformation, were registered using a nonrigid, surface-based method, and the accuracy of different deformation models compared. Registration using a statistical motion model was found to outperform alternative elastic deformation methods in terms of accuracy and robustness, and required substantially fewer target surface points to achieve a successful registration. The mean final target registration error (based on anatomical landmarks) using this method was 1.8 mm. We conclude that a statistical model of prostate deformation provides an accurate, rapid and robust means of predicting prostate deformation from sparse surface data, and is therefore well-suited to a number of interventional applications where there is a need for deformation compensation.

High-dose-rate brachytherapy boost to the dominant intra-prostatic tumor region: hemi-irradiation of prostate cancer

BACKGROUND

To assess the feasibility, toxicity, and outcome of prostate hemi-irradiation with a high-dose-rate brachytherapy (HDR-BT) boost for patients presumed to harbor dominant intra-prostatic tumors in a single lobe.

METHODS

After 3D conformal external radiotherapy (3DCRT) to 64-64.4 Gy, 77 patients with non-metastatic locally aggressive prostate cancer have been treated from 2000 to 2004, with HDR-BT using temporary open MRI-guided (192) Ir implants, to escalate the dose in the boost region. Twenty patients (26%) had one lobe involvement (i.e., one sided endorectal MRI, rectal examination, and biopsies) and were boosted to one side of the gland only. A dose of 12, 14, and 16 Gy in two fractions was delivered to 5, 6, and 9 patients, respectively.

RESULTS

After a median follow-up 69 months, no differences in late rectal toxicity were observed between the unilaterally and bilaterally irradiated cohorts. Although, grade 2 late urinary toxicity was worse in the hemi-irradiated group (P = 0.03), severe grade ≥3 late urinary toxicity at 5 years was not different: 10% versus 8.8% in the unilaterally and bilaterally irradiated cohorts, respectively. Grade 4 late urinary toxicity, however, was exclusively observed in patients boosted to both lobes (5/57, 8.8%). Five-year biochemical relapse-free survival was 79.7% versus 70.5% for the unilateral and bilateral boost groups, respectively (P = 0.99).

CONCLUSION

Prostate hemi-irradiation with a HDR-BT boost to the dominant tumor region may be considered when rectal examination, MRI, and biopsies suggest one lobe involvement. Nevertheless, strict dosimetric optimization is needed in order to further reduce the risk of late severe toxicity.

The effect of the scanning pathway in high-intensity focused ultrasound therapy on lesion production

Because tumors are much larger in size compared with the beam width of high-intensity focused ultrasound (HIFU), raster scanning throughout the entire target is conventionally performed for HIFU thermal ablation. Thermal diffusion affects the temperature elevation and the consequent lesion formation. As a result, the lesion will grow continuously over the course of HIFU therapy. The purpose of this study was to investigate the influence of scanning pathways on the overall thermal lesion. Two new scanning pathways, spiral scanning from the center to the outside and spiral scanning from the outside to the center, were proposed with the same HIFU parameters (power and exposure time) for each treatment spot. The lesions produced in the gel phantom and bovine liver were compared with those using raster scanning. Although more uniform lesions can be achieved using the new scanning pathways, the produced lesion areas (27.5 ± 12.3 mm(2) and 65.2 ± 9.6 mm(2), respectively) in the gel phantom are significantly smaller (p < 0.05) than those using raster scanning (92.9 ± 11.8 mm(2)). Furthermore, the lesion patterns in the gel phantom and bovine liver were similar to the simulations using temperature and thermal dose-threshold models, respectively. Thermal diffusion, the scanning pathway and the biophysical aspects of the target all play important roles in HIFU lesion production. By selecting the appropriate scanning pathway and varying the parameters as ablation progresses, HIFU therapy can achieve uniform lesions while minimizing the total delivered energy and treatment time.

MR to ultrasound registration for image-guided prostate interventions

A deformable registration method is described that enables automatic alignment of magnetic resonance (MR) and 3D transrectal ultrasound (TRUS) images of the prostate gland. The method employs a novel "model-to-image" registration approach in which a deformable model of the gland surface, derived from an MR image, is registered automatically to a TRUS volume by maximising the likelihood of a particular model shape given a voxel-intensity-based feature that represents an estimate of surface normal vectors at the boundary of the gland. The deformation of the surface model is constrained by a patient-specific statistical model of gland deformation, which is trained using data provided by biomechanical simulations. Each simulation predicts the motion of a volumetric finite element mesh due to the random placement of a TRUS probe in the rectum. The use of biomechanical modelling in this way also allows a dense displacement field to be calculated within the prostate, which is then used to non-rigidly warp the MR image to match the TRUS image. Using data acquired from eight patients, and anatomical landmarks to quantify the registration accuracy, the median final RMS target registration error after performing 100 MR-TRUS registrations for each patient was 2.40 mm.

High-intensity focused ultrasound for prostate cancer: a systematic review

High-intensity focused ultrasound (HIFU) has recently been promoted as a non-invasive treatment option for prostate cancer. This systematic review sought to evaluate the evidence comparing it with standard treatment in patients with localised prostate cancer. The literature review included searches of MEDLINE, EMBASE, the Cochrane Library, annual meetings' abstracts and websites of evidence-based practice guideline producers. Studies were included if they were randomised controlled trials comparing HIFU with current management approaches, or were meta-analyses, systematic reviews or practice guidelines addressing HIFU. No randomised controlled trials or meta-analyses were identified. Seven systematic reviews and two practice guidelines were identified; neither contained randomised controlled trials. Adjusting the selection criteria to include case series found 34 clinical studies of HIFU. Twenty-nine evaluated HIFU as the primary treatment and five examined HIFU as salvage treatment for recurrence after radiotherapy. In most studies the outcomes used to determine efficacy were negative biopsy rates or prostate-specific antigen (PSA) levels. Among the 29 studies of HIFU as the primary treatment, negative biopsy rates ranged from 35 to 95% in 21 studies, a PSA nadir of ≤0.5 ng/ml ranged from 55 to 91% in 10 studies and mean PSA nadirs ranged from 0 to 1.9 ng/ml in 17 studies. Five studies reported 5-year disease-free survival rates ranging from 55 to 95%. Among five studies of HIFU as salvage treatment, negative biopsy rates ranged from 73 to 84% in four studies, a PSA nadir of ≤0.5 ng/ml ranged from 57 to 66% in three studies and mean PSA nadirs were 1.97 and 2.38 ng/ml in two studies, respectively. Current evidence on HIFU use in prostate cancer patients is of low quality, rendering it difficult to draw conclusions about its efficacy. Until results from case series are confirmed in prospective studies, the widespread use of HIFU is not supported.

Theoretical and experimental study on temperature elevation behind ribs caused by weakly focused ultrasound

Temperature distribution in tissues behind ribs produced by weakly focused ultrasound had been calculated using Pennes bioheat equation and the validity of the theoretical model was experimentally confirmed in vitro using porcine live. We found that the position of the maximum temperature in tissue is strongly influenced by the distance between the transducer and ribs, while the gap between ribs is the determining factor for the maximum achievable temperature. Within the focal length, when the distance between the transducer and ribs increases, the maximum temperature increases and its position shifts away from the transducer. The rib width has little effect on the position of the maximum temperature but affects the achievable peak temperature. Our results provide useful information for treating liver cancers using ultrasound induced hyperthermia.

Focal therapy in prostate cancer: determinants of success and failure

Focal therapy is emerging as a potential challenge to the standard of care for localized prostate cancer. Short-term quality-of-life outcomes such as genitourinary side effects, anxiety levels, and global measures of quality of life using validated questionnaires are vital although proof-of-concept trials and retrospective case series have already established lower toxicity from focal therapy in some detail. Defining what outcomes will be measured and what defines a successful focal treatment in the medium and long term is problematic. Measuring long-term efficacy or effectiveness within a randomized trial is somewhat straightforward since hard endpoints are measured such as presence or absence of metastatic disease and/or death. However, owing to the long natural history of localized prostate cancer detected in the modern prostate-specific antigen screening era, with these events usually occurring a minimum of 10 years after therapy makes such a long-term trial large, costly, and probably unfeasible now. This article discusses the optimal determinants of success or failure for focal therapy that require careful consideration within multicenter trials evaluating medium-term oncological efficacy.

Prostate cancer in the elderly

Prostate cancer is the most frequent malignancy in men and predominantly in elderly men. The issue of prostate cancer is likely to assume greater importance with progressive aging of the population. With frequent use of PSA testing most patients were diagnosed with localized cancer even in senior adults. Cancer-specific mortality is low in elderly men with prostate cancer and is dependent on the aggressiveness of the tumor. Currently, no established guidelines for the management of prostate cancer in the elderly exist, and treatment of senior adults with localized cancer is not optimal. While elderly men with indolent disease will not benefit from curative treatment, some patients with aggressive cancers will progress if not adequately treated. Comorbidity is the main predictor of life expectancy in the elderly. In everyday clinical practice, treatment decisions are much more influenced by age than by comorbidity. Curative treatment is an effective treatment option for selected elderly with localized prostate cancer. Conversely, most elderly men with prostate cancer received hormonal therapy, although the benefit of hormonal therapy in localized cancer is not clear and is associated with severe toxicities in some patients. In conclusion, there is a need for more risk stratified approaches for the management of prostate cancer in the elderly to avoid unnecessary intervention in men who unlikely benefit from such intervention, and allow treatment in those who might benefit from it.

Design and characterization of a high-power ultrasound driver with ultralow-output impedance

We describe a pocket-sized ultrasound driver with an ultralow-output impedance amplifier circuit (less than 0.05 ohms) that can transfer more than 99% of the voltage from a power supply to the ultrasound transducer with minimal reflections. The device produces high-power acoustical energy waves while operating at lower voltages than conventional ultrasound driving systems because energy losses owing to mismatched impedance are minimized. The peak performance of the driver is measured experimentally with a PZT-4, 1.54 MHz, piezoelectric ceramic, and modeled using an adjusted Mason model over a range of transducer resonant frequencies. The ultrasound driver can deliver a 100 V(pp) (peak to peak) square-wave signal across 0-8 MHz ultrasound transducers in 5 ms bursts through continuous wave operation, producing acoustic powers exceeding 130 W. Effects of frequency, output impedance of the driver, and input impedance of the transducer on the maximum acoustic output power of piezoelectric transducers are examined. The small size, high power, and efficiency of the ultrasound driver make this technology useful for research, medical, and industrial ultrasonic applications.

Adjuvant approaches to enhance cryosurgery

Molecular adjuvants can be used to enhance the natural destructive mechanisms of freezing within tissue. This review discusses their use in the growing field of combinatorial or adjuvant enhanced cryosurgery for a variety of disease conditions. Two important motivations for adjuvant use are: (1) increased control of the local disease in the area of freezing (i.e., reduced local recurrence of disease) and (2) reduced complications due to over-freezing into adjacent tissues (i.e., reduced normal functional tissue destruction near the treatment site). This review starts with a brief overview of cryosurgical technology including probes and cryogens and major mechanisms of cellular, vascular injury and possible immunological effects due to freeze-thaw treatment in vivo. The review then focuses on adjuvants to each of these mechanisms that make the tissue more sensitive to freeze-thaw injury. Four broad classes of adjuvants are discussed including: thermophysical agents (eutectic forming salts and amino acids), chemotherapuetics, vascular agents and immunomodulators. The key issues of selection, timing, dose and delivery of these adjuvants are then elaborated. Finally, work with a particularly promising vascular adjuvant, TNF-alpha, that shows the ability to destroy all cancer within a cryosurgical iceball is highlighted.

[Radical transurethral resection of the prostate. An alternative therapy for the treatment of prostate cancer]

The value of radical transurethral resection of prostate cancer (TURPC) as an alternative therapy was investigated in this prospective study. From January 1995 to July 2008, 533 patients with a median age of 67 years (range 40-89 years) and with clinically localized prostate cancer were resected by the corresponding author with curative intention. The tumor stages were as follows: pT1 8%; pT2 61%; pT3 31%; G1 2%; G2 80%; G3 18%. TURPC requires continuous low-pressure irrigation with the irrigator liquid level at 10 cm water above the pubic region. It also requires a suprapubic trocar, a resectoscope with a 28F sheath, an autoregulated electrosurgical unit, and video monitoring. The prostate is resected completely with peripheral capsule and seminal vesicles. The specimen is retrieved in fractions for correct histopathological staging. If indicated, laparoscopic staging lymphadenectomy is performed. A secondary session for control of positive margins follows after 8 weeks. The transfusion rate was 1.5%, revision for hemorrhage 2.4%, lung embolism 0.2%, bladder neck incision 14%, grade 2 incontinence 0.6% out of 314, and impotence 30% out of 136. The prostate-specific antigen (PSA) nadir was < or =0.2 ng/ml in 95% of 444 cases. PSA recurrence at 5 years was 6% for pT1, 18% for pT2, and 31% for pT3. Postoperative survival at 10 years was 96% for pT1, 91% for pT2, and 85% for pT3 patients. Prostate cancer can be resected transurethrally with reasonable oncological results. The outcome with respect to survival and PSA recurrence is comparable with the results of other published procedures. Low-pressure irrigation with a suprapubic trocar is mandatory for safe performance.

[EAU guidelines on prostate cancer]

OBJECTIVES

To present a summary of the 2007 version of the European Association of Urology (EAU) guidelines on prostate cancer (PCa).

METHODS

A literature review of the new data emerging from 2004 to 2007 was performed by the working panel. The guidelines have been updated, and the level of evidence/grade of recommendation was added to the text based on a systematic review of the literature, which included a search of online databases and bibliographic reviews.

RESULTS

A full version is available at the EAU Office or at www.uroweb.org. Systemic prostate biopsy under ultrasound guidance is the preferred diagnostic method. Active treatment is mostly recommended for patients with localized disease and a long life expectancy, with radical prostatectomy being shown to be superior to watchful waiting in a prospective randomized trial. Nerve-sparing radical prostatectomy represents the approach of choice in organ-confined disease; neoadjuvant androgen deprivation demonstrates no improvement of outcome variables. Radiation therapy should be performed with at least 72 and 78 Gy in low-risk and intermediate- to high-risk PCa, respectively. Monotherapeutic androgen deprivation is the standard of care in metastatic PCa; intermittent androgen deprivation might be an alternative treatment option for selected patients. Follow-up is largely based on prostate-specific antigen and a disease-specific history with imaging only indicated when symptoms occur. Cytotoxic therapy with docetaxel has emerged as the reference treatment for metastatic hormone-refractory PCa.

CONCLUSIONS

The knowledge in the field of PCa is rapidly changing. These EAU guidelines on PCa summarize the most recent findings and put them into clinical practice.

Prospective comparison of five mediators of the systemic response after high-intensity focused ultrasound and targeted cryoablation for localized prostate cancer

OBJECTIVE

To evaluate whether high-intensity focused ultrasound (HIFU) is less invasive than targeted cryoablation of the prostate (TCAP), as experimental studies suggest that the acute-phase reaction is proportional to surgery-induced tissue damage.

PATIENTS AND METHODS

Between May 2004 and December 2007, 127 consecutive patients undergoing HIFU (71) or TCAP (56) in our departments were assessed prospectively. Blood samples were collected 24 h before (T0), during surgery (T1), at the end of anaesthesia (T2), and at 12 (T3), 24 (T4) and 36 h after surgery (T5). The extent of the systemic response to surgery-induced tissue trauma was measured by assessing the levels of acute-phase markers tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), IL-10, C-reactive protein (CRP) and serum amyloid A (SAA), at all sampling times in all patients.

RESULTS

The median (interquartile range) age in the HIFU and TCAP groups was 70 (62-77) and 68 (59-75) years, respectively (P = 0.4). Baseline levels (T0) of TNF-alpha, IL-6, IL-10, CRP and SAA were comparable in both groups. The levels of all four markers increased during both procedures; the median values were higher for TCAP at T2 (P = 0.02, 0.001, <0.001 and 0.06), T3 (P < 0.001, 0.009, 0.003 and 0.001), T4 (P = 0.007, <0.001, 0.005 and <0.001) and T5 (P < 0.001, 0.004, <0.001 and 0.02), respectively. IL-6 was also higher for TCAP at T1 (P = 0.03). IL-10 did not change at the different sampling times.

CONCLUSION

The tissue trauma and associated invasiveness of HIFU is less than that of TCAP, based on the variables objectively measured in this study.