Intraoperative cavernous nerve stimulation during nerve sparing radical prostatectomy: how and when?

Association of Age With Risk of Adverse Pathological Findings at Radical Prostatectomy in Men With Gleason Score 6 Prostate Cancer

This cohort study examines the association of older age with risk of adverse pathological findings at radical prostatectomy in men with biopsy-confirmed Gleason score 6 prostate cancer.

Prostate Cancers Detected by Magnetic Resonance Imaging–Targeted Biopsies Have a Higher Percentage of Gleason Pattern 4 Component and Are Less Likely to Be Upgraded in Radical Prostatectomies

Context.—

In Gleason score (GS) 7 prostate cancers, the quantity of Gleason pattern 4 (GP 4) is an important prognostic factor and influences treatment decisions. Magnetic resonance imaging (MRI)–targeted biopsy has been increasingly used in clinical practice.

Objective.—

To investigate whether MRI-targeted biopsy may detect GS 7 prostate cancer with greater GP 4 quantity, and whether it improves biopsy/radical prostatectomy GS concordance.

Design.—

A total of 243 patients with paired standard and MRI-targeted biopsies with cancer in either standard or targeted or both were studied, 65 of whom had subsequent radical prostatectomy. The biopsy findings, including GS and tumor volume, were correlated with the radical prostatectomy findings.

Results.—

More prostate cancers detected by MRI-targeted biopsy were GS 7 or higher. Mean GP 4 percentage in GS 7 cancers was 31.0% ± 29.3% by MRI-targeted biopsy versus 25.1% ± 29.5% by standard biopsy. A total of 122 of 218 (56.0%) and 96 of 217 (44.2%) prostate cancers diagnosed on targeted biopsy and standard biopsy, respectively, had a GP 4 of 10% or greater (P = .01). Gleason upgrading was seen in 12 of 59 cases (20.3%) from MRI-targeted biopsy and in 24 of 57 cases (42.1%) from standard biopsy (P = .01). Gleason upgrading correlated with the biopsy cancer volume inversely and GP 4 of 30% or less in standard biopsy. Such correlation was not found in MRI-targeted biopsy.

Conclusions.—

Magnetic resonance imaging–targeted biopsy may detect more aggressive prostate cancers and reduce the risk of Gleason upgrading in radical prostatectomy. This study supports a potential role for MRI-targeted biopsy in the workup of prostate cancer and inclusion of percentage of GP 4 in prostate biopsy reports.

The role of MRI in active surveillance for prostate cancer

Approximately one in seven American men will be diagnosed with prostate cancer during his lifetime, and at least 50% of newly diagnosed patients will present with low-risk disease. In the last decade, the decision-making paradigm for management has shifted due to high rates of disease detection and overtreatment, attributed to prostate-specific antigen screening, with more men deferring definitive treatment for active surveillance. The advent of multiparametric magnetic resonance imaging (MP-MRI) and MRI/ transrectal ultrasound-guided fusion-guided prostate biopsy has refined the process of diagnosis, identifying patients with clinically-significant cancer and larger disease burden who would most likely benefit from intervention. In parallel, the utilization of MP-MRI in the surveillance of low-grade, low-volume disease is on the rise, reflecting support in a growing body of literature. The aim of this review is to appraise and summarize the data evaluating the role of magnetic resonance imaging in active surveillance for prostate cancer.

Role of multiparametric magnetic resonance imaging in early detection of prostate cancer

Abstract

Most prostate cancers (PC) are currently found on the basis of an elevated PSA, although this biomarker has only moderate accuracy. Histological confirmation is traditionally obtained by random transrectal ultrasound guided biopsy, but this approach may underestimate PC. It is generally accepted that a clinically significant PC requires treatment, but in case of an non-significant PC, deferment of treatment and inclusion in an active surveillance program is a valid option. The implementation of multiparametric magnetic resonance imaging (mpMRI) into a screening program may reduce the risk of overdetection of non-significant PC and improve the early detection of clinically significant PC. A mpMRI consists of T2-weighted images supplemented with diffusion-weighted imaging, dynamic contrast enhanced imaging, and/or magnetic resonance spectroscopic imaging and is preferably performed and reported according to the uniform quality standards of the Prostate Imaging Reporting and Data System (PIRADS). International guidelines currently recommend mpMRI in patients with persistently rising PSA and previous negative biopsies, but mpMRI may also be used before first biopsy to improve the biopsy yield by targeting suspicious lesions or to assist in the selection of low-risk patients in whom consideration could be given for surveillance.

Teaching Points

• MpMRI may be used to detect or exclude significant prostate cancer.

• MpMRI can guide targeted rebiopsy in patients with previous negative biopsies.

• In patients with negative mpMRI consideration could be given for surveillance.

• MpMRI may add valuable information for the optimal treatment selection.

Evolution of a CDC Public Health Research Agenda for Low-Risk Prostate Cancer

Men with prostate cancer face difficult choices when selecting a therapy for localized prostate cancer. Comparative data from controlled studies are lacking and clinical opinions diverge about the benefits and harms of treatment options. Consequently, there is limited guidance for patients regarding the impact of treatment decisions on quality of life. There are opportunities for public health to intervene at several decision-making points. Information on typical quality of life outcomes associated with specific prostate cancer treatments could help patients select treatment options. From 2003 to present, the Division of Cancer Prevention and Control at CDC has supported projects to explore patient information-seeking behavior post-diagnosis, caregiver and provider involvement in treatment decision making, and patient quality of life following prostate cancer treatment. CDC's work also includes research that explores barriers and facilitators to the presentation of active surveillance as a viable treatment option and promotes equal access to information for men and their caregivers. This article provides an overview of the literature and considerations that initiated establishing a prospective public health research agenda around treatment decision making. Insights gathered from CDC-supported studies are poised to enhance understanding of the process of shared decision making and the influence of patient, caregiver, and provider preferences on the selection of treatment choices. These findings provide guidance about attributes that maximize patient experiences in survivorship, including optimal quality of life and patient and caregiver satisfaction with information, treatment decisions, and subsequent care.

The effect of urologist experience on choosing active surveillance for prostate cancer

PURPOSE

To evaluate the impact of the urologist's experience in selecting active surveillance (AS) versus immediate treatment (IT) for low-risk prostate cancer.

METHODS

Men with low-risk prostate cancer were enrolled from March 2011 to August 2013 at 13 medical centers in Kaiser Permanente Southern California. The AS cohort was defined as men who had cT1-T2a stage prostate cancer, prostate-specific antigen <10 ng/ml, a biopsy revealing Gleason grade ≤6, fewer than three biopsy cores positive, ≤50 % cancer in any core, and not undergone immediate therapy (surgery, radiation, other) within 6 months following diagnosis. The urologist's experience (age, number of years in practice, number of robotic surgeries performed, and fellowship experience in oncology and/or robotics) was then compared between AS and IT cohorts.

RESULTS

A total of 4754 men were diagnosed with prostate cancer, and 713 men satisfied with inclusion criteria; 433 (60.7 %) and 280 (39.3 %) chose AS and IT, respectively. A total of 87 urologists were included. Univariate and multivariate adjusted analyses revealed no differences in urologist's age or years in practice. Patients who saw urologists who had performed ≥50 robotic surgeries were less likely to choose AS (OR 0.40, 95 % CI 0.25-0.66). Patients who saw urologists with a fellowship in oncology and/or robotics were more than twice as likely to choose AS (OR 2.27, 95 % CI 1.38-3.75).

CONCLUSION

These data suggest that the decision to pursue AS may be influenced by the urologist's experience.

Prognostic prostate tissue biomarkers of potential clinical use

In prostate biopsies and in prostatectomy specimens, the Gleason score remains the strongest prognosticator of prostate cancer progression, in addition to serum PSA level and DRE findings, in spite of numerous potential biomarkers discovered during the last few decades. Inter- and intratumoural heterogeneity may have limited the employment of tissue biomarkers on prostate biopsies. Nevertheless, the monoclonality of morphologically heterogeneous (Gleason score 7) tumour foci would suggest that genetic biomarkers, arising early in prostate carcinogenesis, may overcome issues related to intratumoural heterogeneity. In spite of the above limitations, a few biomarkers including the proliferation marker Ki-67 and genetic markers such as c-MYC and PTEN have consistently shown their independent prognostic impact both for biochemical recurrence and for clinical outcome parameters such as metastatic disease or prostate-specific mortality. The routine application of biomarkers requiring immunostaining (e.g. Ki-67) has particularly been hindered by the lack of standardized protocols for processing and scoring, while the application of fluorescence in situ hybridization (FISH) technology is considered more labour intensive but better standardized. Future steps to enhance the uptake of prostate tissue biomarkers should be focused on prospective studies, particularly on prostate biopsy specimens, using protocols that are highly standardized for the processing and scoring of the biomarkers. A few recently developed RNA-based test signatures may provide an alternative to FISH or immunohistochemistry-based tests.

Interventions for sexual dysfunction following treatments for cancer

BACKGROUND

The proportion of people living with and surviving cancer is growing. This has led to increased awareness of the importance of quality of life including sexual function in people with cancer. Sexual dysfunction (SD) is a potential long-term complication of cancer treatments.

OBJECTIVES

Evaluate effectiveness of interventions for SD following treatments for cancer and their adverse effects.

SEARCH STRATEGY

The Cochrane Pain, Palliative & Supportive Care Register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PsycInfo, AMED, CINAHL, Dissertation Abstracts and NHS Research Register were searched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) were included that assessed the effectiveness of a treatment for SD. The trial population comprised of adults of either sex who at trial entry had developed SD as a consequence of cancer treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted the data and assessed trial quality. Meta-analysis was considered for trials with comparable key characteristics.

MAIN RESULTS

Eleven RCTs with a total of 1743 participants were identified. The quality of the trials was poor. Ten trials explored interventions for SD in men following treatments for non-metastatic prostate cancer. One trial explored effectiveness in women of a lubricating vaginal cream following radiotherapy for cervical cancer. The strongest evidence (from four trials) was on oral phosphodiesterase type 5 (PDE5) inhibitors for erectile dysfunction (ED) following radiotherapy of the prostate or radical prostatectomy. The results using validated measures in all trials significantly favoured those in the PDE5 inhibitor group(s). The combined results of two trials indicated a significantly greater improvement in ED in the PDE5 inhibitor groups (odds ratio (OR) 10.09 95% confidence interval (CI) 6.20 to 16.43). Negative effects were few and usually mild to moderate headaches or flushing. One trial reported more clinically serious events including six events of tachycardia and six of chest pain. Following prostate cancer treatments there was some evidence that PDE5 inhibitors are more effective in combination with acetyl-L-carnitine and propionyl-L-carnitine and that sexual counselling improves self-administration of prostaglandin intra-cavernous injection for SD. There was some evidence following treatment for prostate cancer that transurethral alprostadil and vacuum constriction devices reduce SD, although in both trials negative effects were fairly common. There is some evidence that vaginal lubricating creams reduce SD.

AUTHORS' CONCLUSIONS

PDE5 inhibitors are an effective treatment for SD secondary to treatments for prostate cancer. Other interventions identified need to be tested in further RCTs. The SD interventions in this review are not representative of the range available for men and women. Further evaluations are needed for these interventions for SD following cancer treatments.

Reconstruction of cavernous nerves by nerve grafts to restore potency: contemporary review of technical principles and basic anatomy

PURPOSE OF REVIEW

The review discusses the efficacy of reconstructing the neurovascular bundle to regain sexual function if nerve-sparing prostatectomy is unfeasible.

RECENT FINDINGS

Eleven studies could be found describing the reconstruction of neurovascular bundles. All reconstructive procedures displayed technical inadequacies. The effectiveness of unilateral neurovascular bundle reconstruction remains statistically insignificant when compared with procedures without reconstruction. The efficacy of reconstructing both neurovascular bundles ranges between 0 and 43%. Concerning basic anatomy, the neurovascular bundle contains fibers innervating the cavernous nerves, prostate, rectum, and levator ani muscle. The terms cavernous nerve and neurovascular bundle have often been wrongly considered synonymous. The pelvic splanchnic nerves probably do not join the neurovascular bundle proximal to the bladder/prostate junction but rather at variable distances from 10 to 20 mm distal to it. Therefore, described proximal coaptation sites at the bladder/prostate junction possibly encompass only the hypogastric nerve.

SUMMARY

Modest clinical results are partly due to inadequate surgical techniques and are mainly due to the anatomical and topographical complexity of the cavernous nerves. Contemporary nerve grafting techniques probably do not allow for the regeneration of all cavernous nerves.

Significance of electrostimulation in detecting neurovascular bundle during radical prostatectomy

OBJECTIVE

The reported rate of erectile dysfunction after nerve-sparing prostatectomy varies according to physicians. Because exact preservation of the neurovascular bundle (NVB) solely depends on the judgment of the physician, he or she should try to correctly identify the NVB and also avoid neurophysiologic injury of the NVB during the procedure. The purpose of the present study is to assess the status of the NVB preservation by physician's judgment at the operation, the changes in intracavernous pressure related to intraoperative electrical stimulation and postoperative histopathological examination.

PATIENTS AND METHODS

Thirty-eight patients who underwent nerve-sparing radical prostatectomy judged by intraoperative electrical stimulation of the NVB were included in this study. Bilateral, unilateral and non-nerve-sparing procedures were performed in 18, 17, and 3 cases, respectively. The NVB preservation evaluated by intraoperative physician's judgment was compared to that evaluated by postoperative histopathological examination. Furthermore, the NVB preservation evaluated by intraoperative electrical stimulation was compared to that by physician's judgment and postoperative histopathological examination.

RESULTS

For 68 of 76 NVB (89.5%), intraoperative subjective judgment and histopathological assessment were identical. For 66 of 76 NVB (86.8%), electrical stimulation findings and the physician's judgments were identical, and for 70 of 76 NVB (92.1%), electrical stimulation findings and histopathological findings were identical.

CONCLUSION

Even if physicians are convinced of a successful nerve-sparing procedure, there are some cases in which the NVB is not preserved accurately or neurophysiological damage is suffered. Therefore, intraoperative electrical stimulation of the NVB as well as the cavernosal nerve is very useful in evaluation of NVB preservation.

The Effects of Cavernous Nerve Grafting following Surgically Induced Loss of Erectile Function in a Large-Animal Model

BACKGROUND

Prostate cancer is the second most common cause of cancer deaths in men in the United States. Many patients experience partial or complete loss of erectile function following prostatectomy. The cavernous nerves can be reconstructed intraoperatively using sural nerve grafts in an attempt to restore erectile function.

METHODS

In this study, multiple anatomical dissections and neurologic assessments were used to define the position and histologic parameters of the cavernous nerve in a canine model. The subsequent experimental design included three groups of adult mongrel dogs followed for an 8-month period. Group 1, the control group, underwent bilateral nerve ablation to substantiate surgically induced loss of erectile function. Group 2, the "sham" group, underwent exploration only. Group 3 underwent bilateral cavernous nerve ablation with bilateral sural nerve graft reconstruction. Erectile function was evaluated with indirect electrical nerve and manual penile stimulation preoperatively and 1, 2, 4, 6, and 8 months postoperatively. Direct nerve stimulation and histologic analysis was preformed at the first operation and at the time the animals were euthanized at 8 months.

RESULTS

Bilateral cavernous nerve ablation resulted in a significant loss of erectile function for 8 months postoperatively in the control animals. The sham animals demonstrated preservation of erectile function immediately following exploration. The animals in the grafted group demonstrated a significant return of erectile function by 4 months compared with preoperative measurements and by 2 months compared with control animals.

CONCLUSIONS

This study establishes the first large-animal model for surgically induced loss of erectile function with successful cavernous nerve graft reconstruction, and it provides the unique opportunity to explore the effects of changes to this model in the future.

Recent neuroanatomical studies on the neurovascular bundle of the prostate and cavernosal nerves: clinical reflections on radical prostatectomy

The neurovascular bundle of the prostate and cavernosal nerves have been used to describe the same structure ever since the publication of the first studies on the neuroanatomy of the lower urogenital tract of men, studies that were prompted by postoperative complications arising from radical prostatectomy. In urological surgery every effort is made to preserve or restore the neurovascular bundle of the prostate to avoid erectile dysfunction (ED). However, the postoperative potency rates are yet to be satisfactory despite all advancements in radical prostatectomy technique. As the technology associated with urological surgery develops and topographical studies on neuroanatomy are cultivated, new observations seriously challenge the classical teachings on the topography of the neurovascular bundle of the prostate and the cavernosal nerves. The present review revisits the classical and most recent data on the topographical anatomy of the neurovascular bundle of the prostate and cavernosal nerves and their implications on radical prostatectomy techniques.

Intraoperative identification and neurophysiologic parameters to verify pelvic autonomic nerve function during total mesorectal excision for rectal cancer

BACKGROUND

Preservation of parasympathetic and sympathetic nerves is required to avoid urogenital function disturbances after total mesorectal excision (TME) for rectal carcinoma. This study sought to determine whether intraoperative stimulation of parasympathetic nerves with monitoring of bladder contraction is useful in meeting this demand.

STUDY DESIGN

In a prospective pilot study, 17 patients, 11 men and 6 women, underwent TME with pelvic autonomic nerve preservation performed by an experienced surgeon. The parasympathetic nerves were stimulated by an electrostimulation device (Screener 3625, Medronic), and the resulting bladder contraction was measured manometrically in all patients. Variations in pulse rate and voltage were measured to determine optimal stimulation parameters. A standardized questionnaire was used to record urogenital function disturbances. Residual urine volume was measured by ultrasound pre- and postoperatively. Shortterm outcomes data were evaluated to establish a possible association between intraoperative test results and postoperative bladder function.

RESULTS

In 15 of 17 patients undergoing TME with pelvic autonomic nerve preservation for rectal carcinoma, the parasympathetic nerves were identified based on nerve stimulation-induced bladder contraction. Two patients with negative results on intraoperative nerve stimulation had persisting bladder dysfunction requiring an indwelling catheter after discharge from hospital. In spite of a short median followup of 2 months (range 1 to 4 months), in 7 of 10 men with intact erectile function prior to surgery, postoperative erectile dysfunction could be excluded. The study showed a pulse rate of 35 Hz and an electric potential of 12 V to be optimal stimulation parameters, associated with a mean intravesical pressure rise of 12.7 cm H(2)O (range 2.8 to 18.0 cm H(2)O).

CONCLUSIONS

Intraoperative nerve stimulation with monitoring of intravesical pressure represents a technically simple procedure for the identification and verification of function of pelvic parasympathetic nerves during TME for rectal carcinoma.

Erectile function after radical prostatectomy: a review

OBJECTIVES

Although the high rate of erectile dysfunction (ED) following prostatectomy is well recognised, the aetiology and pathophysiology have not yet been fully elucidated. We examined the current literature as to aetiology, treatment and possible prevention of ED following prostatectomy.

METHOD

Review of the literature by a Medline search.

CONCLUSION

The most important predictors of erectile function are pre-operative erectile function and the nerve sparing nature of the procedure. The former is determined by age and vascular risk-factors whereas the latter is decided by the stage of the tumour and the skill of the surgeon. The value of intraoperative nerve mapping seems limited and the importance of nerve grafting is uncertain. Natural recovery of erection can take as long as 24 months. Patients complain about a lack of professional support. Symptomatic therapy may be applied according to the current general standards of treatment in men with ED.

Intraoperative parasympathetic nerve stimulation with tumescence monitoring during total mesorectal excision for rectal cancer

BACKGROUND

Unilateral or bilateral division of the parasympathetic nerves during resection of rectal cancer may result in sexual erectile dysfunction. The purposes of this project were twofold: to determine the ability to demonstrate penile tumescence in response to parasympathetic nerve stimulation after rectal cancer resection and to correlate the nerve stimulation response with clinical sexual function 6 months after operation.

STUDY DESIGN

In 21 consecutive male patients with normal erectile function undergoing total mesorectal excision, cavernous nerve identification and integrity before and after pelvic dissection were assessed intraoperatively, both visually by an experienced surgeon and by using the CaverMap nerve stimulator. The minimal effective current necessary to produce a 2% increase in penile tumescence was recorded for both the left- and right-sided nerves, primarily the largest nerve trunk, S3. Postclearance stimulation data were then correlated with sexual function outcomes, specifically erection and orgasm at 6 months after surgery.

RESULTS

The operating surgeon's visual assessment of the pelvic autonomic nerve's integrity after pelvic dissection was deemed intact in 20 of the 21 patients (95.2%). Of the 20 patients who were evaluated with CaverMap after completion of total mesorectal excision, 17 (85%) had tumescence response after nerve stimulation on either side, and 3 patients (15%) had unilateral response only. Of the 19 patients evaluated for sexual function 6 months after surgery, 18 (94.7%) had normal function, including the 3 patients with only unilateral nerve stimulation tumescence response.

CONCLUSIONS

Intraoperative mapping of the parasympathetic nerve trunks with the CaverMap nerve stimulator may be a valuable aid to less experienced pelvic surgeons and may help in autonomic nerve preservation during total mesorectal excision clearance.

Cavermap-assisted sural nerve interposition graft during radical prostatectomy

Wide excision of the neurovascular bundle and interposition nerve grafting of the cavernous nerves when there is suspected extracapsular extension at the posterolateral prostatic margin are logical applications of improved understanding of pelvic neuroanatomy. Although the indications for neurovascular bundle excision will remain controversial for the foreseeable future, evidence suggests that neurovascular bundle excision improves cancer control in some patients. The ability to predict extracapsular extension reliably at the neurovascular bundle would be a powerful addition to the urologist's armamentarium. The authors have shown, as proof of principle in bilaterally resected neurovascular bundle at the time of RRP, that sural nerve grafting can restore erectile function. The authors' data also support a role for sural nerve grafting in unilateral neurovascular bundle excision. Although the side effects of sural nerve harvest are minor, the ability to predict preoperatively which patients will benefit from such grafts would reduce the number of failures. The success of the authors' interposition nerve-grafting project has resulted, in part, from the use of a multidisciplinary team approach that includes experienced oncologic surgeons and a plastic surgeon with extensive microsurgical and nerve-grafting experience. The technique for sural nerve grafting described herein gives urologists an additional tool to improve patients' quality of life without compromising the chances of success in treating prostate cancer.