Systematic review of the safety and efficacy of osseointegration prosthesis after limb amputation

BACKGROUND

Osseointegration, an approach for direct skeletal attachment of a prosthesis to an amputated limb, may address many of the problems associated with socket prostheses. The safety of osseointegration remains uncertain. The aim of this study was to summarize evidence on functional and clinical outcomes, as well as adverse effects of osseointegration for patients with a limb amputation.

METHODS

MEDLINE, Embase, Web of Science and the Cochrane Library were searched to April 2018. Eligible studies were observational, case and qualitative studies, and RCTs conducted in patients with a limb amputation, who were managed with osseointegrated prostheses and had follow-up data.

RESULTS

Twenty-two eligible articles comprising 13 unique studies were included. No RCT was identified. Apart from three case reports that comprised one to five patients, the sample size of studies ranged from 11 to 100 participants. All relevant studies reported improvement in functional outcomes (walking ability, prosthetic use and mobility), satisfaction and quality of life following osseointegration, compared with their preoperative status or when using a conventional socket prosthesis. Infection rates ranged from 1 (95 per cent c.i. 0 to 5) to 77 (59 to 88) per cent. The majority of infections were described as low-grade soft tissue or superficial infections related to the skin-implant interface, and were treated effectively with antibiotics. None of the studies reported additional amputation or death as a result of osseointegration.

CONCLUSION

Osseointegration after limb amputation improves prosthetic use, comfort when sitting, walking ability, mobility, gait and quality of life. However, it is associated with an increased risk of soft tissue infection.

Hyperglycaemia-induced resistance to Docetaxel is negated by metformin: a role for IGFBP-2

The incidence of many common cancers varies between different populations and appears to be affected by a Western lifestyle. Highly proliferative malignant cells require sufficient levels of nutrients for their anabolic activity. Therefore, targeting genes and pathways involved in metabolic pathways could yield future therapeutics. A common pathway implicated in energetic and nutritional requirements of a cell is the LKB1/AMPK pathway. Metformin is a widely studied anti-diabetic drug, which improves glycaemia in patients with type 2 diabetes by targeting this pathway. We investigated the effect of metformin on prostate cancer cell lines and evaluated its mechanism of action using DU145, LNCaP, PC3 and VCaP prostate cancer cell lines. Trypan blue dye-exclusion assay was used to assess levels of cell death. Western immunoblotting was used to determine the abundance of proteins. Insulin-like growth factor-binding protein-2 (IGFBP-2) and AMPK genes were silenced using siRNA. Effects on cell morphology were visualised using microscopy. IGFBP-2 gene expression was assessed using real-time RT-PCR. With DU145 and LNCaP cells metformin alone induced cell death, but this was reduced in hyperglycaemic conditions. Hyperglycaemia also reduced the sensitivity to Docetaxel, but this was countered by co-treatment with metformin. LKB1 was required for the activation of AMPK but was not essential to mediate the induction of cell death. An alternative pathway by which metformin exerted its action was through downregulation of IGFBP-2 in DU145 and LNCaP cells, independently of AMPK. This finding could have important implications in relation to therapeutic strategies in prostate cancer patients presenting with diabetes.

Patient-Reported Outcomes after Monitoring, Surgery, or Radiotherapy for Prostate Cancer

BACKGROUND

Robust data on patient-reported outcome measures comparing treatments for clinically localized prostate cancer are lacking. We investigated the effects of active monitoring, radical prostatectomy, and radical radiotherapy with hormones on patient-reported outcomes.

METHODS

We compared patient-reported outcomes among 1643 men in the Prostate Testing for Cancer and Treatment (ProtecT) trial who completed questionnaires before diagnosis, at 6 and 12 months after randomization, and annually thereafter. Patients completed validated measures that assessed urinary, bowel, and sexual function and specific effects on quality of life, anxiety and depression, and general health. Cancer-related quality of life was assessed at 5 years. Complete 6-year data were analyzed according to the intention-to-treat principle.

RESULTS

The rate of questionnaire completion during follow-up was higher than 85% for most measures. Of the three treatments, prostatectomy had the greatest negative effect on sexual function and urinary continence, and although there was some recovery, these outcomes remained worse in the prostatectomy group than in the other groups throughout the trial. The negative effect of radiotherapy on sexual function was greatest at 6 months, but sexual function then recovered somewhat and was stable thereafter; radiotherapy had little effect on urinary continence. Sexual and urinary function declined gradually in the active-monitoring group. Bowel function was worse in the radiotherapy group at 6 months than in the other groups but then recovered somewhat, except for the increasing frequency of bloody stools; bowel function was unchanged in the other groups. Urinary voiding and nocturia were worse in the radiotherapy group at 6 months but then mostly recovered and were similar to the other groups after 12 months. Effects on quality of life mirrored the reported changes in function. No significant differences were observed among the groups in measures of anxiety, depression, or general health-related or cancer-related quality of life.

CONCLUSIONS

In this analysis of patient-reported outcomes after treatment for localized prostate cancer, patterns of severity, recovery, and decline in urinary, bowel, and sexual function and associated quality of life differed among the three groups. (Funded by the U.K. National Institute for Health Research Health Technology Assessment Program; ProtecT Current Controlled Trials number, ISRCTN20141297 ; ClinicalTrials.gov number, NCT02044172 .).

Erectile function post robotic radical prostatectomy: technical tips to improve outcomes?

Robotic surgery is becoming more and more commonplace. At the same time, so are complications, especially related to erectile function. The population being diagnosed with cancer is younger, with more aggressive cancers and higher expectations for good erectile function postoperatively. We conduct a retrospective analysis of literature over 20 years for Embase and Medline. Search terms used include (Robotic) AND (prostatectomy) AND (erectile function). There are a variety of multifactorial causes, resulting in worsening ED post-robotic radical prostatectomy; however, there are a number of treatments that can support this. There is much we can do to help prevent patients getting postoperative erectile dysfunction post-radical surgery. However, part of this is management of realistic patient expectations.

Hyperglycaemia-induced chemoresistance of prostate cancer cells due to IGFBP2

Clinically relevant prostate cancer (PCa) is more frequent in Westernised societies and increasingly men have co-morbidities associated with a Western lifestyle, primarily diabetes, characterised by hyperinsulinaemia and hyperglycaemia. IGFs and their binding proteins (IGFBPs) are important mediators of the effects of nutrition on growth and play a key role in the development of PCa. We used DU145, PC3 and LNCaP PCa cell lines to examine how hyperglycaemia altered their response to docetaxel. Trypan Blue dye-exclusion assay was used to determine the percentage of cell death. Protein abundance was determined using western immunoblotting. Levels of IGFBP2 were measured using an ELISA. IGFBP2 gene silencing was achieved using siRNA technology. DNA methylation was assessed using combined bisulphide restriction analysis. Acetylation status of histones H3 and H4 associated with IGFBP2 gene was assessed using chromatin immunoprecipitation assay. Hyperglycaemia reduced docetaxel-induced apoptosis by 40% for DU145 cells and by 88% for LNCaP cells. This reduced cell death was mediated by a glucose-induced up-regulation of IGFBP2, as silencing IGFBP2 negated the survival effect of high glucose. Glucose increased IGFBP2 via increasing the acetylation of histones associated with the IGFBP2 gene promoter. This finding could have important implications in relation to therapeutic strategies as epigenetic modulation could be reversible.

Clinical presentation and initial management of black men and white men with prostate cancer in the United Kingdom: the PROCESS cohort study

Background:

In the United States, Black men have a higher risk of prostate cancer and worse survival than do White men, but it is unclear whether this is because of differences in diagnosis and management. We re-examined these differences in the United Kingdom, where health care is free and unlikely to vary by socioeconomic status.

Methods:

This study is a population-based retrospective cohort study of men diagnosed with prostate cancer with data on ethnicity, prognostic factors, and clinical care. A Delphi panel considered the appropriateness of investigations and treatments received.

Results:

At diagnosis, Black men had similar clinical stage and Gleason scores but higher age-adjusted prostate-specific antigen levels (geometric mean ratio 1.41, 95% confidence interval (95% CI): 1.15–1.73). Black men underwent more investigations and were more likely to undergo radical treatment, although this was largely explained by their younger age. Even after age adjustment, Black men were more likely to undergo a bone scan (odds ratio 1.37, 95% CI: 1.05–1.80). The Delphi analysis did not suggest differential management by ethnicity.

Conclusions:

This UK-based study comparing Black men with White men found no evidence of differences in disease characteristics at the time of prostate cancer diagnosis, nor of under-investigation or under-treatment in Black men.

Optimal Nutrition Should Improve the Outcome and Costs of Radical Cystectomy

INTRODUCTION

Nutritional support has been demonstrated to improve recovery from radical cystectomy, but is expensive and when used inappropriately may actually increase the costs and morbidity of surgery. We sought to establish national patterns of practice with regard to feeding following cystectomy in the UK.

AIMS AND METHODS

Following consultation with the specialist nutrition team, a questionnaire was designed to investigate the feeding strategy after cystectomy and dispatched by post to all UK urologists.

RESULTS

The majority (60%) of respondents employed a traditional strategy of resting the bowel and feeding orally after bowel recovery. A minority used either early total parenteral nutrition (TPN; 18.5%) or enteral nutrition (6.5%), but a larger proportion (29%) felt enteral nutrition was the 'optimal' feeding regime. Only 30% used guidelines and 52% felt trials would help to establish a nutrition strategy following cystectomy.

CONCLUSION

There is little evidence that TPN improves the outcome of cystectomy and it may actually increase morbidity and costs, whereas enteral nutrition may improve recovery. Despite this evidence TPN is widely used by urologists whereas enteral nutrition is used infrequently. Implementation of an evidence-based feeding regime after cystectomy is likely to reduce the morbidity and financial costs of cystectomy.

Do height-related variations in insulin-like growth factors underlie the associations of stature with adult chronic disease?

Tall people, particularly those with long legs, have an increased risk of developing cancer but a reduced risk of cardiovascular disease and type II diabetes. We examined associations of stature and body mass index with IGF-I, IGF-II, and IGF binding protein (IGFBP)-2 and IGFBP-3 in 274 men aged 50-70 yr to investigate whether variations in growth factor levels underlie associations of anthropometry with a number of adult diseases. Height and leg and trunk length were not strongly associated with circulating levels of IGF-I, IGF-II, or IGFBP-3. The molar ratio of IGF-I/IGFBP-3 increased with increases in the leg/trunk length ratio (P = 0.06). IGFBP-2 was positively associated with leg length and inversely associated with trunk length. Mean levels of IGFBP-2 (in nanograms per milliliter) across quartiles of increasing leg length were 504.4 493.6, 528.7, and 578.8 (P(trend) = 0.06), and for trunk length were 615.2, 507.2, 498.6, 488.5 (P(trend) < 0.01), suggesting that variations in IGFBP-2, or a factor influencing its levels in the circulation, may contribute to biological mechanisms underlying height-disease associations. We conclude that whereas growth-influencing exposures during childhood, which may operate through effects on IGF-I levels, have long-term influences on disease risk, they do not necessarily program IGF-I levels throughout life. The associations of anthropometry with IGFBP-2 merit additional investigation.

Are diet-prostate cancer associations mediated by the IGF axis? A cross-sectional analysis of diet, IGF-I and IGFBP-3 in healthy middle-aged men

We examined the association of diet with insulin-like growth factors (IGF) in 344 disease-free men. Raised levels of IGF-I and/or its molar ratio with IGFBP-3 were associated with higher intakes of milk, dairy products, calcium, carbohydrate and polyunsaturated fat; lower levels with high vegetable consumption, particularly tomatoes. These patterns support the possibility that IGFs may mediate some diet-cancer associations.

Management options for gynaecomastia and breast pain associated with nonsteroidal antiandrogen therapy : case report series

OBJECTIVE

To present management options for gynaecomastia and mastodynia associated with nonsteroidal antiandrogen therapy, supported by relevant data and case studies.

BACKGROUND

Gynaecomastia (male breast enlargement) and breast pain/ sensitivity (mastodynia or mastalgia) are pharmacologically expected adverse effects of nonsteroidal antiandrogen therapy for prostate cancer. They are caused by proliferation of glandular tissue in response to an increase in the ratio of estrogen to androgen. Gynaecomastia and mastodynia are benign conditions, and many patients choose to tolerate them as acceptable, usually mild or moderate, adverse effects of therapy. Recent data show that nonsteroidal antiandrogen monotherapy significantly reduces disease progression in localised and locally advanced prostate cancer, a finding that may result in wider and more long-term use of this treatment. Therefore, both clinicians and patients may benefit from increased awareness of the options available for the management of gynaecomastia and mastodynia. Management options, data and case studies: Management options for gynaecomastia and mastodynia are illustrated in a schematic flow diagram. Options identified are: (1) risk reduction using pretreatment breast irradiation; (2) stopping antiandrogen therapy; (3) acceptance of gynaecomastia and/or mastodynia in the context of the significant clinical benefit of antiandrogen treatment; (4) prompt treatment (liposuction/breast tissue excision, hormonal manipulation or pain control with irradiation or analgesics); and (5) later treatment (liposuction/breast tissue excision, hormonal manipulation or pain control with irradiation or analgesics). Where available, relevant data are discussed and the options are illustrated by case studies.

CONCLUSIONS

The risk of developing gynaecomastia is lessened by prophylactic breast irradiation. Following the development of gynaecomastia, treatment options include readjustment of the estrogen-to-androgen ratio using antiestrogens, surgery in the form of liposuction or, for more advanced cases, breast tissue excision. Mastodynia may be controlled by post-treatment irradiation or analgesics.

Expression of neuropilin-1 by human glomerular epithelial cells in vitro and in vivo

Vascular endothelial growth factor (VEGF) is a potent promoter of endothelial mitogenesis and of endothelial permeability. Within the kidney it is synthesized primarily in the visceral glomerular epithelial cells (vGECs); however, the role of VEGF in the glomerulus remains unknown, as does the target cell upon which it acts. Although the target cells may be those of the glomerular endothelium, there are micro-anatomical reasons why this might not be the case. This, therefore, led us to consider the possibility that glomerular VEGF may bind to the vGECs themselves. Since it has been shown that vGECs do not express the main tyrosine kinase VEGF receptors, we chose to study vGEC expression of the more recently described VEGF isoform-specific receptors, the neuropilins. The expression of mRNAs for neuropilin-1, neuropilin-2 and soluble neuropilin was studied in whole kidney, sieved glomeruli and cultured podocytes by reverse transcription-PCR, and neuropilin-1 mRNA expression in isolated single glomeruli was analysed by nested reverse transcription-PCR. The expression of neuropilin-1 protein was investigated in cultured vGECs by Western blotting and immunocytochemistry, and in normal kidney sections by immunohistochemistry. Neuropilin-1 mRNA was detected in whole kidney, single and sieved glomeruli and cultured vGECs. Neuropilin-1 protein was detected in cultured vGECs and in vGECs in normal kidney sections by immunohistochemistry. Thus the present study suggests that vGECs may have the potential to bind the VEGF that they secrete. Functional studies will be required to address the potential significance of this finding in terms of an autocrine loop or VEGF sequestration.

Diagnosis, management and screening of early localised prostate cancer

The incidence of prostate cancer is rising worldwide, caused mainly by demographic factors, particularly the increasingly elderly population and, more importantly, the increasing number of cases identified following prostate specific antigen (PSA) testing. It is commonly quoted that many more men die with prostate cancer than of it. Autopsy/post-mortem studies show that while a very high proportion of elderly men have histological evidence of the disease, a much smaller proportion develop clinically apparent cancer. The natural history of prostate cancer is poorly understood, but progression appears to be related to stage and grade of tumour. Prostate cancer can be diagnosed by digital rectal examination (DRE), serum PSA test, and/or transrectal ultrasound (TRUS), with confirmation by biopsy. Each test identifies a proportion of cancers, with higher rates of detection when they are used in combination. The tests are also used to determine which tumours are localised within the prostate and are, thus, potentially treatable. Unfortunately, clinical staging is unreliable, with approximately one half of all tumours upstaged following surgery. Three major treatment options are available for localised prostate cancer: radical prostatectomy, radical radiotherapy and conservative management (involving monitoring and treatment of symptoms). Although radical treatment rates are rising, good quality evidence concerning their comparative effectiveness and cost-effectiveness is lacking. Observational studies of highly selected patient groups suggests that there may be a slightly lower mortality rate following radical treatments compared with conservative management, but there has been very little research into treatment complications and quality of life of men after any of the treatments. In the past, investigations of prostate cancer were reserved largely for patients exhibiting symptoms, but the introduction of the PSA test has opened up the possibility of screening healthy men for the disease. Observational studies suggest that DRE and PSA, combined with TRUS and biopsy, can identify localised prostate cancer in 3-5% of men, although the tests do result in a number of false positives and negatives. Major questions remain concerning the natural history of the disease, potential costs (financial, social and psychological) of a screening programme, and the effectiveness and cost-effectiveness of treatments for localised disease. The lack of good quality data and the strength of these concerns means that population screening for prostate cancer cannot be recommended.

Interstitial laser coagulation in the treatment of benign prostatic hyperplasia using a diode-laser system with temperature feedback

OBJECTIVE

To report the initial results of the treatment of patients with benign prostatic hyperplasia using interstitial laser coagulation (ILC) performed with a temperature-sensing laser system.

PATIENTS AND METHODS

Twenty-five patients were treated using ILC and in 12, 78 temperature-power curves were recorded. The aim of the treatment was to maintain a temperature of 100 degrees C during the entire treatment cycle, using the temperature-triggered feed-back system. The time to reach the maximum temperature, the maximum temperature and the energy delivered were related to the location of the punctures within the prostate. The clinical outcome at 1 and 3 months was evaluated with symptom scores and uroflowmetry variables.

RESULTS

Heating at the apex seemed to require less energy to achieve and maintain higher temperatures than heating of the median lobe or base of the prostate. Patients improved markedly 1 and 3 months after treatment; the respective mean symptom scores improved from 20.6 before treatment to 9.4 and 6.9, the maximum urinary flow rates from 9.1 mL/s to 14.1 mL/s and 20.3 mL/s and the post-void residual volume decreased significantly from 71 mL to 31 mL and 11 mL. No significant complications (incontinence, impotence or haemorrhage requiring transfusion) occurred.

CONCLUSION

The energy needed to achieve coagulation differed at sites within the prostate, depending on local circumstances. Good results were obtained using the tissue-adaptive laser system.

Initial human clinical experience with diode laser interstitial treatment of benign prostatic hyperplasia

OBJECTIVES

To report the initial results of treatment of outlet obstruction induced by benign prostatic hyperplasia (BPH) using interstitial laser coagulation performed with the Indigo 830 nm diode laser system.

METHODS

A group of 112 men with lower urinary tract symptoms caused by BPH underwent treatment with the Indigo 830 nm laser system between October 1994 and November 1995. Patients were assessed prior to treatment and at specified post-treatment intervals for symptom score, uroflow, postvoid residual, and prostate volume. Adverse events and changes in laboratory parameters were monitored at each post-treatment visit to investigate safety of the procedure.

RESULTS

Symptom score decreased from 20.9 at initial measurement to 9.6 at 3 months after procedure and 7.9 at 6 months. Uroflow rate increased from 8.0 mL/s initially to 15.2 and 14.2 mL/s at 3 and 6 months, respectively. Residual bladder volumes decreased from 105 mL initially to 59 and 38 mL at 3 and 6 months, respectively. There were no major complications (impotence, sustained incontinence, significant blood loss). Minor complications occurred in a small number of patients but were generally associated with urinary tract infection in patients with catheters. Three patients (2.7%) required retreatment and underwent transurethral resection of the prostate.

CONCLUSIONS

Interstitial laser coagulation using an 830-nm diode laser system appears to be a promising new treatment, with substantial improvements in objective and subjective parameters of obstruction and a favorable side-effect profile.

Prostate-specific antigen and prognosis in patients with metastatic prostate cancer--a multivariable analysis of prostate cancer mortality

OBJECTIVE

To analyse the prognostic significance of pre- and post-treatment serum prostate-specific antigen (PSA) levels, together with a variety of other factors, in a multivariable analysis of survival in men with stage D2 prostate cancer.

PATIENTS AND METHODS

Cox's proportional hazards model was used to compare survival in 134 men with stage D2 metastatic prostate cancer followed prospectively over a 4 year period, using both univariable and multivariable models. The influence of the following factors on survival was analysed: pre- and post-treatment PSA (both absolute and percentage values), age, treatment, testosterone, pre- and post-treatment alkaline phosphatase (absolute and percentage values), acid phosphatase, haemoglobin, symptom score and performance status and extent of disease on bone scan.

RESULTS

Pre-treatment PSA levels did not significantly influence survival. Similarly, a low absolute post-treatment PSA level at 3 months after the start of treatment conferred no survival advantage relative to patients with a high PSA level at this time. A post-treatment percentage PSA of < 10% at 2, 3 and 6 months after commencement of treatment was associated with prolonged survival. Low pre-treatment alkaline phosphatase (less than the upper limit of normal) and high pre-treatment testosterone levels (> or = 10 nmol/L) were similarly associated with prolonged survival.

CONCLUSIONS

The strong influence of post-treatment percentage PSA on survival in patients with stage D2 prostate cancer suggests that the percentage change in bulk of metastatic deposits is more important in determining survival than the absolute volume of tumour. Pre-treatment alkaline phosphatase seems to be a better indicator of tumour activity than pre-treatment PSA. These findings have important implications for the design and analysis of clinical trials of new therapies in men with stage D2 prostate cancer and for the future selection of alternative treatments for patients with this stage of the disease.

What is the 'normal range' for prostate-specific antigen? Use of a receiver operating characteristic curve to evaluate a serum marker

OBJECTIVE

To compare the relative sensitivity and specificity of prostate-specific antigen (PSA) as a test for prostate cancer over a range of PSA values in a variety of patient groups, and to compare the sensitivity and specificity of PSA and prostatic acid phosphatase (PAP).

SUBJECTS AND METHODS

Receiver operating characteristic (ROC) curves (sensitivity plotted against 1-specificity) were constructed to compare the ability of PSA to discriminate men with prostate cancer (n = 257) from those with benign prostatic hyperplasia (BPH) (n = 220) or control patients (n = 164). Receiver operating characteristic curves were also constructed to compare PSA and PAP in 173 men with either BPH or prostate cancer.

RESULTS

When patients with symptomatic BPH and those with advanced prostate cancer are excluded, a PSA of 8 ng/mL has a sensitivity of 94% and a specificity of 98% for prostate cancer. In patients presenting with symptoms suggestive of bladder outflow obstruction, PSA remains a sensitive marker for prostate cancer (93% sensitivity at 10 ng/mL) but its specificity (65%) is poor. PSA is a sensitive test for skeletal metastases but levels of 60-80 ng/mL are required to achieve a specificity of 70% or more. The sensitivity of PSA is far superior to that of PAP.

CONCLUSION

Serum PSA provides good discrimination between patients with and without prostate cancer. The sensitivity and specificity of PSA can be improved by excluding men with symptomatic BPH. The specificity of PSA as a diagnostic test for prostate cancer is reduced in men with symptoms of bladder outflow obstruction. For reasonable sensitivity and specificity, a PSA of 60-80 ng/mL is required for differentiating non-metastatic from metastatic prostate cancer. The ROC curve comparing PSA and PAP provides a graphical demonstration of the superiority of PSA as a tumour marker. The ability of PSA to identify prostate cancer can be improved by selecting out groups of patients and by adjusting the cut-off level of PSA to the population under study.

Magnetic resonance imaging in the staging of bladder cancer

Magnetic resonance imaging (MRI) scans were performed on 55 bladder cancer patients on whom clinicopathological staging was available from transurethral resection and cystectomy specimens. The overall accuracy of MRI scanning in this group was 84%, although true concordance rates are debatable without open surgical correlation. In the subgroup of 25 patients who had accurate open surgical correlation (from cystectomy, laparotomy or post mortem) the concordance rate was 76% with MRI. Errors occurred mainly in the T3 group of tumours, with 2 being overstaged and 2 being understaged out of a total of 12 in the open surgical correlation group (66% accuracy). Difficulties were also encountered in staging tumours at the bladder base, with an error rate of 22% (2 of 9) for T4 tumours in this area. With regard to lymph node staging there was a 100% (5 of 5) specificity in defining pathologically involved nodes but there was a false negative rate of 15% (3 of 19). Although it has many advantages over CT scanning, MRI produces a significant error rate in terms of over- and under-staging invasive tumours. There are difficulties associated with detecting minimal involvement of adjacent organs and lymph nodes as well as determining the exact depth of muscle penetration. Improvements may come in the future with the use of contrast enhancement agents such as gadolinium as well as more advanced machines.

High-dose intravenous estrogen therapy in advanced prostatic carcinoma. Use of serum prostate-specific antigen to monitor response

High-dose intravenous estrogen therapy was shown to be effective in relieving bone pain due to metastatic disease in 22 of 29 (75.9%) men with advanced hormone-resistant prostate cancer. This clinical response was accompanied by significant falls in serum prostate-specific antigen (PSA) levels in 13 (44.8%) patients. It is suggested that this clinical benefit is due to a direct inhibitory effect of estrogen on prostate cancer cells.