The Prostate Cancer Rehabilitation Clinic: a biopsychosocial clinic for sexual dysfunction after radical prostatectomy

Purpose

The most prevalent intervention for localized prostate cancer (pca) is radical prostatectomy (rp), which has a 10-year relative survival rate of more than 90%. The improved survival rate has led to a focus on reducing the burden of treatment-related morbidity and improving the patient and partner survivorship experience. Post-rp sexual dysfunction (sdf) has received significant attention, given its substantial effect on patient and partner health-related quality of life. Accordingly, there is a need for sdf treatment to be a fundamental component of pca survivorship programming.

Methods

Most research about the treatment of post-rp sdf involves biomedical interventions for erectile dysfunction (ed). Although findings support the effectiveness of pro-erectile agents and devices, most patients discontinue use of such aids within 1 year after their rp. Because side effects of pro-erectile treatment have proved to be inadequate in explaining the gap between efficacy and ongoing use, current research focuses on a biopsychosocial perspective of ed. Unfortunately, there is a dearth of literature describing the components of a biopsychosocial program designed for the post-rp population and their partners.

Results

In this paper, we detail the development of the Prostate Cancer Rehabilitation Clinic (pcrc), which emphasizes multidisciplinary intervention teams, active participation by the partner, and a broad-spectrum medical, psychological, and interpersonal approach.

Conclusions

The goal of the pcrc is to help patients and their partners achieve optimal sexual health and couple intimacy after rp, and to help design cost-effective and beneficial rehabilitation programs.

Enablers and barriers in delivery of a cancer exercise program: the Canadian experience

BACKGROUND

Exercise is an important therapy to improve well-being after a cancer diagnosis. Accordingly, cancer-exercise programs have been developed to enhance clinical care; however, few programs exist in Canada. Expansion of cancer-exercise programming depends on an understanding of the process of program implementation, as well as enablers and barriers to program success. Gaining knowledge from current professionals in cancer-exercise programs could serve to facilitate the necessary understanding.

METHODS

Key personnel from Canadian cancer-exercise programs (n = 14) participated in semistructured interviews about program development and delivery.

RESULTS

Content analysis revealed 13 categories and 15 subcategories, which were grouped by three organizing domains: Program Implementation, Program Enablers, and Program Barriers. ■ Program Implementation (5 categories, 8 subcategories) included Program Initiation (clinical care extension, research project expansion, program champion), Funding, Participant Intake (avenues of awareness, health and safety assessment), Active Programming (monitoring patient exercise progress, health care practitioner involvement, program composition), and Discharge and Follow-up Plan.■ Program Enablers (4 categories, 4 subcategories) included Patient Participation (personalized care, supportive network, personal control, awareness of benefits), Partnerships, Advocacy and Support, and Program Characteristics.■ Program Barriers (4 categories, 3 subcategories) included Lack of Funding, Lack of Physician Support, Deterrents to Participation (fear and shame, program location, competing interests), and Disease Progression and Treatment.

CONCLUSIONS

Interview results provided insight into the development and delivery of cancer-exercise programs in Canada and could be used to guide future program development and expansion in Canada.

The impact of a BRCA2 mutation on mortality from screen-detected prostate cancer

Background:

Men with a BRCA2 mutation face an increased risk of prostate cancer. These cancers tend to have an aggressive nature and it has not yet been demonstrated that regular screening of BRCA2 carriers is associated with improved survival.

Methods:

We identified 4187 men who underwent a prostate cancer biopsy for an elevated PSA or an abnormal digital rectal examination between 1998 and 2010. We screened the BRCA2 gene in its entirety for mutations and we followed the men for death from prostate cancer until December 2012.

Results:

The 12-year prostate cancer-specific survival rate was 94.3% for men without a BRCA2 mutation and was 61.8% for men with a mutation (P<10⁻⁴; log-rank test).

Conclusions:

The survival of men with screen-detected prostate cancer and a BRCA2 mutation is much poorer than expected.

Effect of total-body prehabilitation on postoperative outcomes: a systematic review and meta-analysis

OBJECTIVE

To systematically review the evidence of pre-operative exercise, known as 'prehabilitation', on peri- and postoperative outcomes in adult surgical populations.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

CENTRAL, Medline, EMBASE, CINAHL, PsycINFO and PEDro were searched from 1950 to 2011.

METHODS

Two reviewers independently examined relevant, English-language articles that examined the effects of pre-operative total-body exercise with peri- and postoperative outcome analysis. Given the nascence of this field, controlled and uncontrolled trials were included. Risk of bias was assessed using the Cochrane Risk of Bias Assessment tool. Only data on length of stay were considered eligible for meta-analysis due to the heterogeneity of measures and methodologies for assessing other outcomes.

RESULTS

In total, 4597 citations were identified by the search strategy, of which 21 studies were included. Trials were generally small (median=54 participants) and of moderate to poor methodological quality. Compared with standard care, the majority of studies found that total-body prehabilitation improved postoperative pain, length of stay and physical function, but it was not consistently effective in improving health-related quality of life or aerobic fitness in the studies that examined these outcomes. The meta-analysis indicated that prehabilitation reduced postoperative length of stay with a small to moderate effect size (Hedges' g=-0.39, P=0.033). Intervention-related adverse events were reported in two of 669 exercising participants.

CONCLUSION

The literature provides early evidence that prehabilitation may reduce length of stay and possibly provide postoperative physical benefits. Cautious interpretation of these findings is warranted given modest methodological quality and significant risk of bias.

Should follow-up biopsies for men on active surveillance for prostate cancer be restricted to limited templates?

OBJECTIVE

To investigate if prostate biopsy templates with fewer cores can be used during active surveillance (AS) for prostate cancer.

METHODS

At present, we use an AS protocol template (ASPT) consisting of 13-17 cores. We hypothesize in the setting of known cancer, sextant (6 cores) or standard extended (10-12 cores) templates, could be used with similar effect. We identified patients in our referral institution database (1997-2009) with entry prostate-specific antigen <10 ng/mL, stage ≤cT2, Gleason sum ≤6, ≤3 cores positive for cancer, <50% of single core involved, and age ≤75 years (N = 272). Patients fulfilling standard criteria for pathologic reclassification (N = 94) at any follow-up biopsy were selected for evaluation. By mapping tumor location on the pathologic reclassification determining biopsy, hypothetical scenarios of sextant or standard extended templates (SET) were compared with our ASPT and examined for frequency of cancer detection and pathologic reclassification.

RESULTS

For the 94 patients analyzed, the median number of cores taken was 9.7 (6-22) at baseline and 15 (14-17) for the reclassification biopsy. The median time between baseline and the pathologic reclassification determining biopsy was 15.4 months. Analysis of subgroupings showed that sextant template would identify 84% of cancers and 47.9% of the reclassification events, whereas SET detected 99% of cancers and 81.9% of patients who pathologically reclassified. When only considering Gleason sum ≥7 related progression events, SET found 16.2% less (n = 57) compared with ASPT (n = 68).

CONCLUSION

When monitoring patients on AS, a 13-17 core template detects more pathologic reclassification than standard sextant (18.1%) or extended (52.1%) biopsy templates.

Exercise in clinical cancer care: a call to action and program development description

A large and convincing body of evidence demonstrates the benefits of exercise for cancer survivors during and after treatment. Based on that literature, more cancer survivors should be offered exercise support and programming. Unfortunately, exercise programs remain an exception rather than the norm in cancer care. Not surprisingly, common barriers to the implementation of exercise programs in oncology include limited resources, expertise, and awareness of benefits on the part of patients and clinicians. To improve the accessibility and cost-effectiveness of cancer exercise programs, one proposed strategy is to combine the resources of hospital and community-based programs with home-based exercise instruction. The present paper highlights current literature regarding exercise programming for cancer survivors, describes the development of an exercise program for cancer patients in Toronto, Canada, and offers experiential insights into the integration of exercise into oncologic care.

Early experience in MRI-guided therapies of prostate cancer: HIFU, laser and photodynamic treatment

Prostate cancer screening has resulted in earlier diagnosis with lower-grade disease, leading to over-detection and over-treatment in a significant number of patients. Current whole-gland radical treatments are associated with significant rates of morbidity. The high prevalence of low-risk disease together with an inability to accurately identify those men harboring more aggressive cancers has led to tremendous research in low-morbidity focal therapies for prostate cancer. This review summarizes the early experiences with focal therapy with emphasis on early applications of laser, high-intensity focuses ultrasound, and photodynamic approaches.

Focal therapy in prostate cancer-report from a consensus panel

PURPOSE

To establish a consensus in relation to case selection, conduct of therapy, and outcomes that are associated with focal therapy for men with localized prostate cancer.

MATERIAL AND METHODS

Urologic surgeons, radiation oncologists, radiologists, and histopathologists from North America and Europe participated in a consensus workshop on focal therapy for prostate cancer. The consensus process was face to face within a structured meeting, in which pertinent clinical issues were raised, discussed, and agreement sought. Where no agreement was possible, this was acknowledged, and the nature of the disagreement noted.

RESULTS

Candidates for focal treatment should have unilateral low- to intermediate-risk disease with clinical stage <or=cT(2a). Prostate size and both tumor volume and tumor topography are important case selection criteria that depend on the ablative technology used. Currently, the best method to ascertain the key characteristics for men who are considering focal therapy is exposure to transperineal template mapping biopsies. MRI of the prostate using novel techniques such as dynamic contrast enhancement and diffusion weighed imaging are increasingly being used to diagnose and stage primary prostate cancer with excellent results. For general use, however, these new techniques require validation in prospective clinical trials. Until such are performed, MRI will, in most centers, continue to be an investigative tool in assessing eligibility of patients for focal therapy.

CONCLUSIONS

Consensus was derived for most of the key aspects of case selection, conduct of treatment, and outcome measures for men who are undergoing focal therapy for localized prostate cancer. The level of agreement achieved will pave the way for future collaborative trials.

Androgens induce oxidative stress and radiation resistance in prostate cancer cells though NADPH oxidase

Androgen deprivation therapy (ADT) facilitates the response of prostate cancer (PC) to radiation. Androgens have been shown to induce elevated basal levels of reactive oxygen species (ROS) in PC, leading to adaptation to radiation-induced cytotoxic oxidative stress. Here, we show that androgens increase the expression of p22^phox and gp91^phox subunits of NADPH oxidase (NOX) and ROS production by NOX2 and NOX4 in PC. Pre-radiation treatment of 22Rv1 human PC cells with NOX inhibitors sensitize the cells to radiation similarly to ADT, suggesting that their future usage may spare the need for adjuvant ADT in PC patients undergoing radiation.

In vivo quantification of fluorescent molecular markers in real-time by ratio imaging for diagnostic screening and image-guided surgery

Future applications of "molecular diagnostic screening" and "molecular image-guided surgery" will demand images of molecular markers with high resolution and high throughput (~ > or =30 frames/second). MRI, SPECT, PET, optical fluorescence tomography, hyper-spectral fluorescence imaging, and bioluminescence imaging do not offer such high frame rates. 2D optical fluorescence imaging can provide surface images with high resolution and high throughput. The ability to accurately quantify the fluorescence in vivo is critical to extract functional information of the disease state, however few methods are available. Here, a ratiometric 2D quantification method is introduced. Through mathematical modeling the performance was evaluated using optical properties that resembled biological tissues with the fluorescent marker Protoporhyrin IX. Experimentally the performance was evaluated in optical phantoms with different optical properties employing a novel prototype clinical imaging system. The clinical feasibility of real-time, image-guided surgery was demonstrated in patients undergoing prostatectomy. Discussed are the reasons why the introduced method leads to an increased quantification performance followed by modifications so it can be applied to novel fluorescent molecular markers as phthalocyanine 4 and dual-fluorescent markers. These offer additional advantages as these can provide a linear response to marker concentration and further minimize the dependence on autofluorescence and optical properties, as demonstrated through modeling.

Expression of the TMPRSS2:ERG fusion gene predicts cancer recurrence after surgery for localised prostate cancer

The prostate-specific gene, TMPRSS2 is fused with the gene for the transcription factor ERG in a large proportion of human prostate cancers. The prognostic significance of the presence of the TMPRSS2:ERG gene fusion product remains controversial. We examined prostate cancer specimens from 165 patients who underwent surgery for clinically localised prostate cancer between 1998 and 2006. We tested for the presence of TMPRSS2:ERG gene fusion product, using RT–PCR and direct sequencing. We conducted a survival analysis to determine the prognostic significance of the presence of the TMPRSS2:ERG fusion gene on the risk of prostate cancer recurrence, adjusting for the established prognostic factors. We discovered that the fusion gene was expressed within the prostate cancer cells in 81 of 165 (49.1%) patients. Of the 165 patients, 43 (26.1%) developed prostate-specific antigen (PSA) relapse after a mean follow-up of 28 months. The subgroup of patients with the fusion protein had a significantly higher risk of recurrence (58.4% at 5 years) than did patients who lacked the fusion protein (8.1%, P<0.0001). In a multivariable analysis, the presence of gene fusion was the single most important prognostic factor; the adjusted hazard ratio for disease recurrence for patients with the fusion protein was 8.6 (95% CI=3.6–20.6, P<0.0001) compared to patients without the fusion protein. Among prostate cancer patients treated with surgery, the expression of TMPRSS2:ERG fusion gene is a strong prognostic factor and is independent of grade, stage and PSA level.

A genome-wide association screen identifies regions on chromosomes 1q25 and 7p21 as risk loci for sporadic prostate cancer

We conducted a genome-wide association study of 3090 sporadic prostate cancer patients and controls using the Affymetrix 10 000 SNP GeneChip. Initial screening of 40 prostate cancer cases and 40 non-cancer controls revealed 237 SNPs to be associated with prostate cancer (P<0.05). Among these SNPs, 33 were selected for further association analysis of 2069 men who had undergone a cancer-screening prostate biopsy. Results identified five loci as being significantly associated with increased prostate cancer risk in this larger sample (rs 1930293, OR=1.7, P=0.03; rs 717809-2p12, OR=1.3, P=0.03; rs 494770-4q34, OR=1.3, P=0.01; rs 2348763-7p21, OR=1.5, P=0.01; rs 1552895-9p22, OR=1.5, P=0.002). To validate these association data, 61 additional HapMap tagSNPs spanning the latter five loci were genotyped in this subject cohort and an additional 1021 men (total subject number=3090). This analysis revealed tag SNP rs 4568789 (chromosome 1q25) and tag SNP rs 13225697 (chromosome 7p21) to be significantly associated with prostate cancer (P-values 0.009 and 0.008, respectively). Haplotype analysis revealed significant associations of prostate cancer with two allele risk haplotypes on both chromosome 1q25 (adjusted OR of 2.7 for prostate cancer, P=0.0003) and chromosome 7p21 (adjusted OR of 1.3, P=0.0004). As linkage data have identified a putative prostate cancer gene on chromosome 1q25 (HPC1), and microarray data have revealed the ETV1 oncogene to be overexpressed in prostate cancer tissue, it appears that chromosome 1q25 and 7p21 may be sites of gene variants conferring risk for sporadic and inherited forms of prostate cancer.

Vascular targeted photodynamic therapy with palladium-bacteriopheophorbide photosensitizer for recurrent prostate cancer following definitive radiation therapy: assessment of safety and treatment response

PURPOSE

Tookad is a novel intravascular photosensitizer. When activated by 763 nm light, it destroys tumors by damaging their blood supply. It then clears rapidly from the circulatory system. To our knowledge we report the first application of Tookad vascular targeted photodynamic therapy in humans. We assessed the safety, pharmacokinetics and preliminary treatment response as a salvage procedure after external beam radiation therapy.

MATERIALS AND METHODS

Patients received escalating drug doses of 0.1 to 2 mg/kg at a fixed light dose of 100 J/cm or escalated light doses of 230 and 360 J/cm at the 2 mg/kg dose. Four optical fibers were placed transperineally in the prostate, including 2 for light delivery and 2 for light dosimetry. Treatment response was assessed primarily by hypovascular lesion formation on contrast enhanced magnetic resonance imaging and transrectal ultrasound guided biopsies targeting areas of lesion formation and secondarily by serum prostate specific antigen changes.

RESULTS

Tookad vascular targeted photodynamic therapy was technically feasible. The plasma drug concentration was negligible by 2 hours after infusion. In the drug escalation arm 3 of 6 patients responded, as seen on magnetic resonance imaging, including 1 at 1 mg/kg and 2 at 2 mg/kg. The light dose escalation demonstrated an increasing volume of effect with 2 of 3 patients in the first light escalation cohort responding and all 6 responding at the highest light dose with lesions encompassing up to 70% of the peripheral zone. There were no serious adverse events, and continence and potency were maintained.

CONCLUSIONS

Tookad vascular targeted photodynamic therapy salvage therapy is safe and well tolerated. Lesion formation is strongly drug and light dose dependent. Early histological and magnetic resonance imaging responses highlight the clinical potential of Tookad vascular targeted photodynamic therapy to manage post-external beam radiation therapy recurrence.

Multicenter phase II study of combined neoadjuvant docetaxel and androgen ablation (ADT) prior to radical prostatectomy (RP) for patients (pts) with high risk localized prostate cancer (LCaP): Pathologic outcomes and 3-year follow-up analyses

5002

Background: Pts with high risk LCaP (cT3, Gleason score > 7 &/or PSA > 20) have an increased risk of relapse with a biochemical failure rate of >50% at 3 years after RP. Docetaxel is active in hormone refractory prostate cancer & potentially beneficial if combined with ADT for treatment naïve disease. The objectives of this trial were to assess the pathologic outcomes & feasibility of docetaxel + ADT in men with LCaP prior to RP. Methods: A phase II multi-center study of newly diagnosed previously untreated pts with clinically LCaP with high-risk features. All pts received ADT (buserelin acetate 6.3 mg q8 weeks x 3 and anti-androgen for 4 weeks) plus docetaxel (35 mg/m2 weekly for 6 out of 8 weeks for 3 cycles) prior to RP. Results: 72 men with a median age of 59 years (range 46–78) were enrolled at 6 sites. Baseline characteristics included: clinical stage T1C, T2 & T3 in 14%, 47% & 39%; and Gleason score <7, 7 & >7 in 10%, 30% & 60% of pts; respectively. Median baseline PSA was 10.8 μg/L (range 1.6–65.6) with PSA < 10 in 47%, 10–20 in 24% & >20 in 29% of pts. Eight pts did not complete protocol therapy because of toxicity (n=4), withdrawal of consent (n=1), or other reasons (n=3). 1 pt had myocardial infarction day 1 post-operatively & 1 pt had DVT 1.5 months after RP. No other major post-operative complications were reported. Of the 64 pts completing protocol therapy, 2 had a complete pathologic response and pathologic stage was T2 in 34 (53%) and T3 in 28 (44%) pts. Four pts had N1 disease & positive surgical margins were identified in 17 (27%). On multivariate Cox regression analysis only baseline Gleason score (=7 vs. >7) was associated with PSA recurrence-free survival (hazard ratio 4.58, 95% CI 1.32–15.93). At a median follow-up of 42.7 months (range 25.6–65.6), 19 (30%) pts have relapsed. Three pts have died at 32.0, 40.0 & 40.3 months, with all deaths attributed to prostate cancer. Conclusions: Combined ADT and docetaxel prior to RP was feasible and resulted in encouraging pathologic outcomes and PSA- recurrence free survival. These data further support the rationale for randomized trials determining the efficacy of chemo-hormonal therapy in pts with clinically LCaP.

[Table: see text]

Maximal androgen blockade for the treatment of metastatic prostate cancer--a systematic review

INTRODUCTION

Maximal androgen blockade (MAB) versus castration alone in patients with metastatic prostate cancer has been extensively evaluated in randomized trials. The inconsistent results have led to the publication of multiple meta-analyses. The present review examines the evidence from meta-analytic reports to determine whether MAB using agents such as flutamide, nilutamide, and cyproterone acetate (CPA) is associated with a survival advantage.

METHODS

We conducted a systematic review of the literature (MEDLINE, EMBASE, and the Cochrane Library through July 2004; CANCERLIT through October 2002) for meta-analyses that compared MAB with castration alone in previously untreated men with metastatic prostate cancer (D1 or D2, N+/M0 or M1). Two reviewers selected papers for eligibility; disagreement was resolved by all the authors through consensus.

RESULTS

The literature search identified six meta-analyses that met the eligibility criteria of the review. Two of those reports were based on individual patient data (IPD), and four were based on data from the published literature. All six meta-analyses pooled data on overall survival. The best evidence came from the largest meta-analysis, conducted by the Prostate Cancer Trialists Collaborative Group and based on IPD (8725 patients) from 27 trials. That analysis detected no difference in overall survival between mab and castration alone at 2 or 5 years. However, a subgroup analysis showed that MAB with nonsteroidal anti-androgens (NSAAS) was associated with a statistically significant improvement in 5-year survival over castration alone (27.6% vs. 24.7%; p = 0.005). The combination of MAB with CPA, a steroidal anti-androgen, was associated with a statistically significant increased risk of death (15.4% vs. 18.1%; p = 0.04). Compared with castration alone, MAB was associated with more side effects (that is, gastrointestinal, endocrine function) and reduced quality of life in domains related to treatment symptoms and emotional functioning.

CONCLUSIONS

The small survival benefit conferred by MAB with NSAA is of questionable clinical significance given the added toxicity and concomitant decline in quality of life observed in patients treated with MAB. Therefore, combined treatment with flutamide or nilutamide should not be routinely offered to patients with meta-static prostate cancer beyond the purpose of blocking testosterone flare. Monotherapy, consisting of orchiectomy or the administration of a luteinizing hormone-releasing hormone agonist is recommended as standard treatment.

Maximal Androgen Blockade for the Treatment of Metastatic Prostate Cancer—A Systematic Review

Introduction: Maximal androgen blockade (mab) versus castration alone in patients with metastatic prostate cancer has been extensively evaluated in randomized trials. The inconsistent results have led to the publication of multiple meta-analyses. The present review examines the evidence from meta-analytic reports to determine whether mab using agents such as flutamide, nilutamide, and cyproterone acetate (cpa) is associated with a survival advantage. Methods: We conducted a systematic review of the literature (medline, embase, and the Cochrane Library through July 2004; cancerlit through October 2002) for meta-analyses that compared mab with castration alone in previously untreated men with metastatic prostate cancer (D1 or D2, N+/M0 or M1). Two reviewers selected papers for eligibility; disagreement was resolved by all the authors through consensus. Results: The literature search identified six meta-analyses that met the eligibility criteria of the review. Two of those reports were based on individual patient data (ipd), and four were based on data from the published literature. All six meta-analyses pooled data on overall survival. The best evidence came from the largest meta-analysis, conducted by the Prostate Cancer Trialists Collaborative Group and based on ipd (8725 patients) from 27 trials. That analysis detected no difference in overall survival between mab and castration alone at 2 or 5 years. However, a subgroup analysis showed that mab with nonsteroidal anti-androgens (nsaas) was associated with a statistically significant improvement in 5-year survival over castration alone (27.6% vs. 24.7%; p = 0.005). The combination of mab with cpa, a steroidal anti-androgen, was associated with a statistically significant increased risk of death (15.4% vs. 18.1%; p = 0.04). Compared with castration alone, mab was associated with more side effects (that is, gastrointestinal, endocrine function) and reduced quality of life in domains related to treatment symptoms and emotional functioning. Conclusions: The small survival benefit conferred by mab with nsaa is of questionable clinical significance given the added toxicity and concomitant decline in quality of life observed in patients treated with mab. Therefore, combined treatment with flutamide or nilutamide should not be routinely offered to patients with meta-static prostate cancer beyond the purpose of blocking testosterone flare. Monotherapy, consisting of orchiectomy or the administration of a luteinizing hormone–releasing hormone agonist is recommended as standard treatment.

6-Hydroxydopamine-induced alterations in blood-brain barrier permeability

Vascular inflammation is well known for its ability to compromise the function of the blood--brain barrier (BBB). Whether inflammation on the parenchymal side of the barrier, such as that associated with Parkinson's-like dopamine (DA) neuron lesions, similarly disrupts BBB function, is unknown. We assessed BBB integrity by examining the leakage of FITC-labeled albumin or horseradish peroxidase from the vasculature into parenchyma in animals exposed to the DA neurotoxin 6-hydroxydopamine (6OHDA). Unilateral injections of 6OHDA into the striatum or the medial forebrain bundle produced increased leakage in the ipsilateral substantia nigra and striatum 10 and 34 days following 6OHDA. Microglia were markedly activated and DA neurons were reduced by the lesions. The areas of BBB leakage were associated with increased expression of P-glycoprotein and beta 3-integrin expression suggesting, respectively, a compensatory response to inflammation and possible angiogenesis. Behavioural studies revealed that domperidone, a DA antagonist that normally does not cross the BBB, attenuated apomorphine-induced stereotypic behaviour in animals with 6OHDA lesions. This suggests that drugs which normally have no effect in brain can enter following Parkinson-like lesions. These data suggest that the events associated with DA neuron loss compromise BBB function.

Risk factors for disease progression in patients with lower urinary tract symptoms/benign prostatic hyperplasia (LUTS/BPH): a systematic analysis of expert opinion

Disease progression has become an important issue for the management of lower urinary tract symptoms/benign prostatic hyperplasia (LUTS/BPH). Although several risk factors have been identified, no specific patient risk profiles have been established that can be useful in the day-to-day management of LUTS/BPH. In this study, an international panel of urologists developed a risk classification based on the attribution of a risk score to 243 unique patient profiles. From the perspective of clinical decision making, it was concluded that postvoid residual, symptom severity and maximum flow rate are the most relevant determinants of the risk of disease progression.

Integrating risk profiles for disease progression in the treatment choice for patients with lower urinary tract symptoms/benign prostatic hyperplasia: a combined analysis of external evidence and clinical expertise

The RAND appropriateness method was used to explore the relevance of risk factors for disease progression in the treatment choice for patients with lower urinary tract symptoms/benign prostatic hyperplasia (LUTS/BPH). A total of, 12 international experts assessed the appropriateness of various treatments for 243 risk profiles. Highest appropriateness rates were found for alpha1-adrenoceptor antagonists (68% of profiles) and combination therapy (46%). A large prostate volume was the dominant argument in favour of 5alpha-reductase inhibitors and combination therapy, but was irrelevant for the choice of surgery. Considerable postvoid residual, severe symptoms and poor maximum flow rate were the most important factors in favour of surgery.

Interstitial microwave thermal therapy and its application to the treatment of recurrent prostate cancer

Interstitial microwave thermal therapy may be an effective alternative to surgery for the treatment of some solid tumours. Arrays of helical antennae can produce complex heating patterns which when combined with active cooling of normal tissue structures can provide conformal heating for thermal coagulation of tumours. The development of a clinical protocol involving phantom and animal model studies, treatment planning, tissue property measurement and methods for on-line treatment monitoring is reviewed. The technology developed has been applied to the problem of recurrent prostate cancer following failed radiation treatment where available curative options are associated with high normal tissue morbidity. The purpose was to develop a treatment option for this group of patients with a very low side-effect profile that would not preclude further treatment if the disease progressed. Results of a Phase I/II trial demonstrate safety, promising efficacy and a low complication rate. As the technology for delivering this treatment matures, larger multi-institutional trials should be considered.

EFFECT OF THE DUAL 5α-REDUCTASE INHIBITOR DUTASTERIDE ON MARKERS OF TUMOR REGRESSION IN PROSTATE CANCER

PURPOSE

In the prostate testosterone is converted to dihydrotestosterone (DHT) by the enzymes 5alpha-reductase (5alphaR) types 1 and 2 (5alphaR1 and 5alphaR2). Suppression of DHT formation by 5alphaR inhibition may be beneficial in early treatment or prevention of prostate cancer. Although 5alphaR2 is the dominant enzyme in the prostate, evidence indicates that 5alphaR1 may be up-regulated in some prostate cancers. This suggests that dual inhibition of both isoenzymes may be more effective than suppression of 5alphaR2 alone in prostate cancer treatment or prevention. In this short-term pilot study we examined the effect of the dual 5alphaR inhibitor dutasteride on markers of tumor regression.

MATERIALS AND METHODS

A total of 46 men with clinically staged T1 or T2 prostate cancer were randomized to receive 5 mg per day of placebo or dutasteride for 6 to 10 weeks before radical prostatectomy. Resected tissues were analyzed to determine the effect of dutasteride on intraprostatic androgen levels, and indices of apoptosis and microvessel density (MVD) in malignant tissue, as well as degree of atrophy in benign tissue.

RESULTS

Treatment with dutasteride caused a 97% decrease in intraprostatic DHT and was associated with a trend toward increased apoptosis. In patients receiving dutasteride for 45 days or more, a significant increase in apoptosis and a trend toward decreased MVD in prostate cancer tissue was observed. Dutasteride treatment was also associated with an 18% decrease in mean benign epithelial cell width compared with placebo (p < 0.0001).

CONCLUSIONS

In this pilot study dutasteride treatment resulted in almost complete suppression of intraprostatic DHT, increased apoptosis and a trend toward decreased MVD. These findings suggest that short-term treatment with dutasteride can cause regression in some prostate cancers.

Updated results of a randomized, double-blind, multicenter sham-controlled trial of microwave thermotherapy with the Dornier Urowave in patients with symptomatic benign prostatic hyperplasia. Urowave Investigators Group

A total of 220 patients with clinical benign prostatic hyperplasia (BPH), an AUA symptom index (AUA SI) of > 13 points, and a peak flow rate of < 12 ml/s were randomly assigned to either active or sham treatment. All treatments were conducted as an outpatient procedure without general anesthesia. Sham-treated patients underwent a simulated 60-min treatment with an indwelling treatment catheter. Patients were followed at 1 week and at 1, 3, and 6 months. The treatments were well tolerated. The AUA SI dropped from 23.6 to 12.6 points at 6 months (P < 0.05) in the active group and from 23.9 to 17.9 points in the sham-treated group (P < 0.05 for the difference between groups). There was a significant difference between the groups at 6 months (P < 0.001). Similar and statistically significant changes occurred regarding the AUA bother index and the quality of life scores. Statistically significant improvements were also noted for the peak flow rate (from 7.7 to 10.6 ml/s at 6 months for the active group and from 8.1 to 9.6 ml/s for the sham-treated group; P < 0.05 for the difference between groups) and for the average flow rate. An improvement in the AUA SI of > 30% was achieved by 72% versus 40% (active versus sham) and an improvement of > 50% was accomplished by 48% versus 21% of the respective patients. Actively treated patients reported more dysuria, urgency, and ejaculatory dysfunction following treatment than did sham-treated patients. Urinary retention occurred in 5.4% of patients. The Dornier Urowave is better in improving symptoms, bother, quality of life, and flow rates than is a sham treatment in patients with symptomatic BPH. The treatments can be given on an outpatient basis with local anesthesia. Adverse events are in general transient and mild in nature. This device compares favorably with other second-generation devices. Extended follow-up is necessary to document the long-term durability of these improvements.

Ultrasound properties of human prostate tissue during heating

Changes in the ultrasound (US) properties of tissue during heating affect the delivery of US thermal therapy and may provide a basis for US image monitoring of thermal therapy. The US attenuation coefficient and backscatter power of fresh human prostate tissue were measured as the tissue was heated. Samples of human prostate were obtained directly from autopsies and heated rapidly to final temperatures of 45 degrees C, 50 degrees C, 55 degrees C, 60 degrees C and 65 degrees C. A 5.0-MHz transducer was scanned in a raster pattern over the tissue and radiofrequency (RF) data were collected at 36 uncorrelated positions. Both attenuation and backscatter were measured over the frequency range 3.5 to 7.0 MHz at each min of a 30-min heating. Little change was observed in attenuation or backscatter at 55 degrees C or less. The attenuation coefficient and backscatter power increased by factors of 1.25 and 5, respectively, during the 60 degrees C heating. During the 65 degrees C heating, the same properties showed increases by factors of 2.7 and 9.

Interstitial microwave thermal therapy for prostate cancer: method of treatment and results of a phase I/II trial

PURPOSE

Interstitial microwave thermal therapy is experimental treatment for prostate cancer with the goal of curing disease, while causing fewer complications than standard treatment options. We present a method for delivering interstitial microwave thermal therapy using microwave radiating helical antennae inserted percutaneously under transrectal ultrasound guidance. We report the results of a trial of this method in 25 patients in whom primary external beam radiation therapy had previously failed. This patient group currently has limited curative options that are associated with a high complication rate. However, these recurrent tumors often remain localized to the prostate, and so they may be amenable to localized therapy.

MATERIALS AND METHODS

Patients with proved prostatic adenocarcinoma were candidates for treatment when prostate specific antigen (PSA) was 15 ng./ml. or less and prostate volume was 50 cc. or less. Followup included PSA measurement, digital rectal examination, urinalysis, and documentation of adverse events at 4, 8, 12 and 24 weeks. Sextant biopsy was performed at week 24. The procedure involved the insertion of 5 antennae percutaneously through a modified brachytherapy template. The antenna arrangement was determined based on computer simulated predictions of temperature throughout the prostate. The prostate was dissected away from the rectum by an injection of sterile saline to provide a thermal barrier that protected the rectum from thermal damage. Temperatures were monitored using interstitial mapping thermistor probes that were also inserted through the template. A minimum peripheral target temperature of 55C but less than 70C was maintained for 15 to 20 minutes, while the urethra, rectum and hydrodissection space remained below 42C. The urethra and rectum were actively cooled in addition to hydrodissection.

RESULTS

Peripheral target temperatures of 55C were achieved. The urethra and rectum remained at a safe temperature. The procedure, including setup and treatment, required approximately 2.5 hours of operating room time. At 24 weeks the PSA nadir was 0.5 ng./ml. or less in 52% of patients and 0.51 to 4 ng./ml. was achieved in an additional 40%. The negative biopsy rate at 24 weeks was 64%, assuming that 3 patients lost to followup would have had positive results. No major complications were observed and in most cases minor complications resolved within 3 months.

CONCLUSIONS

Interstitial microwave thermal therapy for prostate cancer was developed to heat the prostate safely to a cytotoxic temperature. Experience with 25 patients in whom external beam radiation therapy for prostate cancer had failed indicates that the treatment is safe. Although our series indicates that this therapy may be effective, further studies and longer followup are required in larger patient groups to confirm the potential role of this therapy as an option for recurrent and primary prostate cancer.

Helical antenna arrays for interstitial microwave thermal therapy for prostate cancer: tissue phantom testing and simulations for treatment

Interstitial microwave therapy is an experimental treatment for prostate cancer. The objective of this work was to measure the power deposition (specific absorption rate, SAR) patterns of helical microwave antennae both individually and in array patterns that would be useful for clinical treatment protocols. Commercial helical antenna 3D SAR patterns were measured in muscle equivalent phantoms using a thermographic technique. Two array patterns were tested: a 'square' and a 'crescent' array, both surrounding the urethra. To assess the feasibility of pre-treatment planning, the measured SAR patterns were input to a treatment planning computer simulation program based on a series of trans-rectal ultrasound images from a prostate cancer patient. The simulation solved the Pennes linear bioheat heat transfer equation in prostate tissue, with the aim of achieving a target of 55 degrees C at the prostate periphery while not allowing normal surrounding tissues (bladder, urethra, rectum) to rise above 42 C. These criteria could not be met with the square array but they could be met with the crescent array, provided that the prostate was first dissected away from the rectum. This can be done with a procedure such as 'hydrodissection', where sterile saline is injected to separate the prostate and rectum. The results of these SAR measurements and heat transfer simulations indicate that arrays of helical antennae could be used for safe and effective thermal therapy for prostate cancer.

Levels of insulin-like growth factor I (IGF-I) and IGF binding proteins 2 and 3 in serial postoperative serum samples and risk of prostate cancer recurrence

OBJECTIVES

To determine changes of insulin-like growth factor I (IGF-I), IGF binding protein-2 (IGFBP-2), and IGFBP-3 levels in serial postoperative serum samples from prostate cancer patients with and without relapse and to evaluate the prognostic value of these molecules in the recurrence of prostate cancer.

METHODS

From a group of patients with prostate cancer who had been followed for disease recurrence for almost 5 years after radical prostatectomy, we selected 38 patients (cases) who developed recurrent disease and 40 patients (controls) who were in remission. Of these patients, 70 had 4 and 8 had 3 serial postoperative serum samples collected. The median times for serum collection after surgery were 1.5 years for the first serial samples, 2.6 years for the second, 3.5 years for the third, and 4.5 years for the fourth. Serum levels of IGFBP-2, IGFBP-3, and IGF-I were measured, using commercial immunoassay kits.

RESULTS

The study showed lower serum levels of IGFBP-2 and IGFBP-3 in the cases than in controls(P <0.05) but no difference in IGF-I levels between the two groups (P = 0.277). In the sequential samples, IGFBP-2 levels increased over time in the controls (P = 0.014) but did not change in the cases (P = 0.528). There were no increasing or decreasing trends for IGF-I and IGFBP-3 in either case or control group(P >0.05).

CONCLUSIONS

The study suggests that IGFBP-2 may play a role in the progression of prostate cancer, but serum levels of IGFBP-2 as well as IGF-I and IGFBP-3 have no predictive values in the prognosis of prostate cancer.

Evidence of chromosomal instability in prostate cancer determined by spectral karyotyping (SKY) and interphase fish analysis

The way in which cytogenetic aberrations develop in prostate cancer (CaP) is poorly understood. Spectral karyotype (SKY) analysis of CaP cell lines has shown that they have unstable karyotypes and also have features associated with chromosomal instability (CIN). To accurately determine the incidence of de novo structural and numerical aberrations in vitro in CaP, we performed SKY analysis of three independent clones derived from one representative cell line, DU145. The frequent generation of new chromosomal rearrangements and a wide variation in the number of structural aberrations within two to five passages suggested that this cell line exhibited some of the features associated with a CIN phenotype. To study numerical cell-to-cell variation, chromosome 8 aneusomy was assessed in the LNCaP, DU145, and PC-3 cell lines and a patient cohort of 15 CaP primary tumors by interphase fluorescence in situ hybridization (FISH). This analysis showed that a high frequency of numerical alteration affecting chromosome 8 was present in both in vitro and in CaP tissues. In comparison to normal controls, the patient cohort had a statistically significant (P<.05), greater frequency of cells with one and three centromere 8 copies. These data suggest that a CIN-like process may be contributing towards the generation of de novo numerical and structural chromosome abnormalities in CaP.

V89L polymorphism of type-2, 5-alpha reductase enzyme gene predicts prostate cancer presence and progression

OBJECTIVES

The valine (V) to leucine (L) polymorphism of the SRD5A2 gene is associated with 5-alpha reductase-2 activity; patients with the V allele have high activity and patients with the L allele have low activity. We examined whether this polymorphism predicts the presence of prostate cancer in 320 men without cancer who underwent biopsy and cancer progression in 318 men who underwent radical prostatectomy.

METHODS

The effect of the SRD5A2 gene in predicting the presence of prostate cancer was examined using logistic regression analysis, controlling for established risk factors. The effect of the SRD5A2 gene in predicting prostate cancer progression was examined using a nested, matched, case-control design. Most of the participants were white.

RESULTS

Of the 320 men, 158 (49.4%) were found on biopsy to have prostate cancer. The overall distribution of the V/V, V/L, and L/L genotypes was 47.5%, 42.5%, and 10.0%, respectively. The adjusted odds ratio for having prostate cancer for patients with at least one V allele was 2.53 compared with patients with the L/L genotype (P = 0.03). Of the 318 patients with cancer, 80 had biochemically detected recurrence and 238 had no evidence of recurrence. The odds ratio for progression for patients with at least one V allele was 3.32 (95% confidence interval 1.67 to 6.62, P = 0.0006) compared with patients with the L/L genotype.

CONCLUSIONS

Men who have the V allele of the SRD5A2 gene have a twofold increase in the risk of prostate cancer development and an additional twofold increase in the risk of progression compared with men with the L/L genotype.

Emerging pharmacologic therapies for prostate cancer

The last decade has seen explosive growth in the therapy of prostate cancer. Three areas of therapeutics are emerging: 1) new compounds with novel uses; 2) available compounds with new applications; and 3) new compounds applied to established indications. The novel compounds target specific receptor sites of cancer pathways and attack cancer cells with less effect on normal tissue. Earlyphase trials with compounds targeting the endothelin-A and EGF receptors have shown encouraging results in hormone-refractory prostate cancer. In addition, the Early Prostate Cancer Trial of over 8000 men is currently underway to determine the benefit of adjuvant androgen ablation with bicalutamide in men with localized prostate cancer. Early results show a significant 42% reduction in the progression of the disease in the bicalutamide treatment arm. Further, in large, phase 3 clinical trials in patients needing androgen ablation, the GnRH antagonist abarelix caused no testosterone surge and demonstrated a significantly more rapid decline in serum testosterone to the castrate level than did an LHRH agonist analogue. Abarelix should thus have application as a monotherapy in patients who need a rapid onset of action or are at high risk of complications from the clinical flare seen with LHRH agonists. Abarelix also uniquely caused a sustained decline in serum FSH levels, which have been shown in vitro to stimulate prostate cancer cell growth. If these favorable effects can be duplicated in patients, abarelix might also offer a survival benefit.

Magnetic resonance thermometry for predicting thermal damage: an application of interstitial laser coagulation in an in vivo canine prostate model

Magnetic resonance image-guidance for interstitial thermal therapy has proven to be a valuable tool in its traditional role in device localization and, more recently, in monitoring heat deposition within tissue. However, a quantitative understanding of how temperature-time exposure relates to thermal damage is crucial if the predictive value of real-time MR thermal-monitoring is to be fully realized. Results are presented on interstitial laser coagulation of two canine prostate models which are shown to provide an opportunity to evaluate three models of thermal damage based on a threshold maximum temperature, an Arrhenius damage integral, and a temperature-time product. These models were compared to the resultant lesion margin as derived from post-treatment T(1)- and T(2)-weighted MR images, as well as from direct histological evaluation of the excised canine prostate. Histological evaluation shows that the thermal-injury boundary can be predicted from a threshold-maximum temperature of approximately 51 degrees C or an equivalent Arrhenius t(43) period of 200 minutes, but it is not reliably predicted using the temperature-time product. The methods described in this study are expected to have implications for the treatment of benign prostatic hyperplasia and prostate cancer with interstitial laser coagulation, which will be the focus of future human studies.

Magnetic resonance thermometry for predicting thermal damage: an application of interstitial laser coagulation in an in vivo canine prostate model

Magnetic resonance image-guidance for interstitial thermal therapy has proven to be a valuable tool in its traditional role in device localization and, more recently, in monitoring heat deposition within tissue. However, a quantitative understanding of how temperature-time exposure relates to thermal damage is crucial if the predictive value of real-time MR thermal-monitoring is to be fully realized. Results are presented on interstitial laser coagulation of two canine prostate models which are shown to provide an opportunity to evaluate three models of thermal damage based on a threshold maximum temperature, an Arrhenius damage integral, and a temperature-time product. These models were compared to the resultant lesion margin as derived from post-treatment T(1)- and T(2)-weighted MR images, as well as from direct histological evaluation of the excised canine prostate. Histological evaluation shows that the thermal-injury boundary can be predicted from a threshold-maximum temperature of approximately 51 degrees C or an equivalent Arrhenius t(43) period of 200 minutes, but it is not reliably predicted using the temperature-time product. The methods described in this study are expected to have implications for the treatment of benign prostatic hyperplasia and prostate cancer with interstitial laser coagulation, which will be the focus of future human studies.

Construction of the Patient-Oriented Prostate Utility Scale (PORPUS): a multiattribute health state classification system for prostate cancer

Health status indexes, such as the EuroQol, consist of a health state classification system and a set of utility weights. Indexes measure quality of life using a 0-1 utility score. Utilities for outcomes in prostate cancer (PC) are of unique importance, but generic indexes do not represent PC outcomes (e.g., sexual, urinary, bowel dysfunction) well, and may not capture their full impact. As a step toward improved utility measurement, we constructed a classification system for PC. We generated items for each of six health domains and rated their importance using interviews with 10 clinical experts and 80 patients. Key concepts were selected for each domain using item importance weightings, and a set of predetermined criteria. Text was developed to express levels of severity within each domain. Experts and two additional groups of patients (n = 40, n = 96) evaluated textual clarity and endorsed the content validity of the instrument. The final system consists of 10 domains with 4-6 levels each. The content validity of the system was endorsed by patients and experts. In conjunction with a set of utility weights, it may be used to develop a health status index, to improve utility measurement in patients, and to serve as a short psychometric (nonutility) instrument.

Significance of the CAG repeat polymorphism of the androgen receptor gene in prostate cancer progression

PURPOSE

The CAG repeat polymorphism of the androgen receptor gene has been associated with an increased prostate cancer risk, and the repeat length correlated with cancer stage and grade at presentation. Men with an allele length of </= 18 CAG repeats have a 2-fold increase in risk for high-stage or high-grade prostate cancer, compared with patients with a longer CAG repeat. We examined the significance of the CAG repeat polymorphism of the androgen receptor gene for predicting prostate cancer progression among 318 patients treated by radical prostatectomy for clinically localized prostate cancer between 1987 and 1994.

MATERIALS AND METHODS

Leukocyte DNA was collected and genotyping of the CAG repeat polymorphism was performed using a PCR-based direct sequencing method. Risk ratios were calculated for developing biochemical recurrence for patients associated with an allele length of </= 18 CAG repeats, compared with patients with an allele length of >18 CAG repeats, controlling for grade, stage and serum PSA level at diagnosis using Cox proportional hazard modeling.

RESULTS

Overall, the CAG repeat allele was not predictive of recurrence; tumor grade, stage and PSA level at diagnosis were the only predictors of recurrence in a multivariate analysis. However, for patients at low risk for recurrence (Gleason score 2 to 6, stage pT2, and PSA </= 10 ng./ml.), the relative risk of recurrence associated with an allele of </= 18 CAG repeats was 8.07 (95% C.I., 2.02 to 32.2, p = 0.004), compared with patients with an allele length of >18 CAG repeats. In contrast, for patients at high risk of recurrence (Gleason score >/= 7, stage pT3/4, or PSA >10 ng./ml.), the relative risk associated with the </= 18 CAG repeat allele was 0.72 (95% C.I., 0.33 to 1.57, p = 0.41), compared with patients with the >18 CAG repeat allele.

CONCLUSIONS

The length of the CAG repeat polymorphism of the androgen receptor gene may be important for prostate cancer recurrence among patients who are otherwise at low risk for recurrence after radical prostatectomy. These findings have potential implications for patient selection for adjuvant treatment, and for the development of novel treatments.

The clinical burden of prostate cancer in Canada: forecasts from the Montreal Prostate Cancer Model

OBJECTIVES

The incidence of prostate cancer is increasing, as is the number of diagnostic and therapeutic interventions to manage this disease. We developed a Markov state-transition model--the Montreal Prostate Cancer Model--for improved forecasting of the health care requirements and outcomes associated with prostate cancer. We then validated the model by comparing its forecasted outcomes with published observations for various cohorts of men.

METHODS

We combined aggregate data on the age-specific incidence of prostate cancer, the distribution of diagnosed tumours according to patient age, clinical stage and tumour grade, initial treatment, treatment complications, and progression rates to metastatic disease and death. Five treatments were considered: prostatectomy, radiation therapy, hormonal therapies, combination therapies and watchful waiting. The resulting model was used to calculate age-, stage-, grade- and treatment-specific clinical outcomes such as expected age at prostate cancer diagnosis and death, and metastasis-free, disease-specific and overall survival.

RESULTS

We compared the model's forecasts with available cohort data from the Surveillance, Epidemiology and End Results (SEER) Program, based on over 59,000 cases of localized prostate cancer. Among the SEER cases, the 10-year disease-specific survival rates following prostatectomy for tumour grades 1, 2 and 3 were 98%, 91% and 76% respectively, as compared with the model's estimates of 96%, 92% and 84%. We also compared the model's forecasts with the grade-specific survival among patients from the Connecticut Tumor Registry (CTR). The 10-year disease-specific survival among the CTR cases for grades 1, 2 and 3 were 91%, 76% and 54%, as compared with the model's estimates of 91%, 73% and 37%.

INTERPRETATION

The Montreal Prostate Cancer Model can be used to support health policy decision-making for the management of prostate cancer. The model can also be used to forecast clinical outcomes for individual men who have prostate cancer or are at risk of the disease.

The economic burden of prostate cancer in Canada: forecasts from the Montreal Prostate Cancer Model

BACKGROUND

We developed an economic model of prostate cancer management from diagnosis until death. We have used the Montreal Prostate Cancer Model to estimate the total economic burden of the disease in a cohort of Canadian men.

METHODS

Using this Markov state-transition simulation model, we estimated the probability of prostate cancer, annual prostate cancer progression rates and associated direct medical costs according to patient age, tumour stage and grade, and treatment modalities in a 1997 cohort of Canadian men. The estimated lifetime costs of prostate cancer included the costs of clinical staging, initial treatments and complications, follow-up cancer therapies, routine outpatient care, and palliative care following metastatic disease.

RESULTS

The clinical burden of prostate cancer forecasted using the model was similar to the projections of the National Cancer Institute. In the 1997 cohort of 5.8 million Canadian men between 40 and 80 years old, prostate cancer would be diagnosed in an estimated 701,491 men (12.1%) over their lifetime. Direct medical costs would total $9.76 billion, or $3.89 billion when discounted 5% annually.

INTERPRETATION

The Montreal Prostate Cancer Model indicates that the economic burden of prostate cancer to Canada's health care system will be substantial. Further analyses are needed to identify the most efficient means of treating this disease.