Vasectomy and risk of prostate cancer

Vasectomy and prostate cancer risk: a pooled of cohort studies and Mendelian randomization analysis

BACKGROUND

The relationship between vasectomy and the risk of prostate cancer (PCa) remains unclear, with observational studies reporting inconsistent results. To clarify this ambiguity, we embarked on a comprehensive investigation comprising both a meta-analysis and a Mendelian randomization (MR) study. This dual approach aimed to thoroughly examine not only the association but also the causality between undergoing a vasectomy and the subsequent risk of PCa.

METHODS

Our systematic review meticulously examined cohort studies published until January 2024, employing a random effects model for the computation of relative risks (RR) and their 95% confidence intervals (CI). For MR Analysis, we leveraged aggregated data from the IEU Open GWAS database, investigating the correlation between genetic predisposition to vasectomy and PCa. We chose single nucleotide polymorphisms (SNPs) of European descent as instrumental variables (IVs) for this analysis. The primary method for calculating the odds ratios (ORs) and their 95% CIs was inverse variance weighting (IVW). Through sensitivity analysis, we confirmed the robustness of our findings.

RESULTS

Our investigation synthesized data from 19 cohort studies, encompassing over four million participants. The combined analysis revealed a statistically significant link between vasectomy and an elevated risk of PCa across any grade (RR = 1.09; 95%CI: 1.05-1.14; P = 0.001; I² = 83.3%). This association was observed for both localized PCa (RR = 1.08; 95% CI: 1.04-1.13; P < 0.001; I² = 48.8%) and advanced PCa (RR = 1.07; 95% CI: 1.01-1.13; P = 0.016; I² = 0%). Nonetheless, the discovery cohort MR Analysis indicated no genetic causal link between vasectomy and PCa (OR = 0.067; 95%CI = 0.002-1.535; P = 0.09). A validation set in the Finnish population confirmed the robustness of the results. This conclusion remained consistent even after controlling for variables such as prostate-specific antigen (PSA) testing and body mass index (BMI), suggesting that while a statistical association exists, the genetic evidence does not support a causal relationship.

CONCLUSION

The cumulative analysis indicates a possible elevated risk of PCa in patients who have had a vasectomy. However, MR Analysis has not confirmed a direct causal link between vasectomy and PCa. This suggests that the association observed may not stem from direct causation, allowing for the continued consideration of vasectomy as a viable long-term contraceptive choice. Further research is imperative to uncover any factors that could potentially link vasectomy to an increased risk of prostate cancer, aiming to provide a more comprehensive understanding of the implications.

Vasectomy and Risk of Prostate Cancer: A Systematic Review and Meta-analysis

Context

Previous reports have shown an association between vasectomy and prostate cancer (PCa). However, there exist significant discrepancies between studies and systematic reviews due to a lack of strong causal association and residual confounding factors such as prostate-specific antigen (PSA) screening.

Objective

To assess the association between vasectomy and PCa, in both unadjusted and PSA screen-adjusted studies.

Evidence acquisition

We performed a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses. The PubMed, Scopus, and Web of Science databases were searched in January 2022 for studies that analyzed the association between vasectomy and PCa.

Evidence synthesis

A total of 37 studies including 16 931 805 patients met our inclusion criteria. A pooled analysis from all studies showed a significant association between vasectomy and any-grade PCa (odds ratio [OR] 1.23; 95% confidence interval [CI], 1.10–1.37; p < 0.001; I² = 96%), localized PCa (OR 1.08; 95% CI, 1.06–1.11; p < 0.00001; I² = 31%), or advanced PCa (OR 1.07; 95% CI, 1.02–1.13; p = 0.006; I² = 0%). The association with PCa remained significant when the analyses were restricted to studies with a low risk of bias (OR 1.06; 95% CI, 1.02–1.10; p = 0.02; I² = 48%) or cohort studies (OR 1.09; 95% CI, 1.04–1.13; p < 0.0001; I² = 64%). Among studies adjusted for PSA screening, the association with localized PCa (OR 1.06; 95% CI, 1.03–1.09; p < 0.001; I² = 0%) remained significant. Conversely, vasectomy was no longer associated with localized high-grade (p = 0.19), advanced (p = 0.22), and lethal (p = 0.42) PCa.

Conclusions

Our meta-analysis found an association between vasectomy and any, mainly localized, PCa. However, the effect estimates of the association were increasingly close to null when examining studies of robust design and high quality. On exploratory analyses including studies, which adjusted for PSA screening, the association for aggressive and/or advanced PCa diminished.

Patient summary

In this study, we found an association between vasectomy and the risk of developing localized prostate cancer without being able to determine whether the procedure leads to a higher prostate cancer incidence.

Pathological Roles of Reactive Oxygen Species in Male Reproduction

Reactive oxygen species (ROS) are free radicals that have at least one unpaired electron and play specific roles in the human body. An imbalance of ROS and antioxidant levels gives rise to a condition called oxidative stress. High levels of ROS in the male reproductive tract can interfere with its normal functioning and can even pose as toxic to the sperm, inhibiting sperm functioning (including motility) and metabolism. Oxidative stress resulting from ROS and lipid peroxidation is one of the major causes of male infertility including infertility in varicocele patients. These may cause DNA and peroxidative damage and apoptosis. Production of ROS in excess also leads to erectile dysfunction (ED). In recent years, studies have also linked oxidative stress with the development, progress, and therapy response of prostate cancer patients. The present study summarizes the pathological roles of ROS in male reproductive problems such as infertility, ED, and prostate cancer and also provide an insight into the probable mechanism through which ROS exert their pathological impact.

Association between vasectomy and risk of prostate cancer: a meta-analysis

BACKGROUND

The debate over the association between vasectomy and prostate cancer has been lasted about 40 years and there is no sign of stopping. In the present study, we aimed to evaluate whether vasectomy is associated with prostate cancer based on the most comprehensive and up-to-date evidence available.

METHODS

The PubMed, Cochrane Library, and EMBASE databases were systematically searched inception to March 14, 2021 without year or language restriction. Multivariable adjusted risk ratios (RRs) were used to assess each endpoint. Risk of bias was assessed using the Newcastle-Ottawa scale.

RESULTS

A total of 58 studies involving 16,989,237 participants fulfilled inclusion criteria. There was significant association of vasectomy with risk of any prostate cancer (risk ratio, 1.18, 95% CI, 1.07-1.31). Association between vasectomy and advanced prostate cancer (risk ratio, 1.06, 95% CI, 1.01-1.12), low-grade prostate cancer (risk ratio, 1.06, 95% CI, 1.02-1.10), and intermediate-grade prostate cancer (risk ratio, 1.12, 95% CI, 1.03-1.22) were significant. There was no significant association between vasectomy and prostate cancer-specific mortality (risk ratio, 1.01, 95% CI, 0.93-1.10).

CONCLUSIONS

This study found that vasectomy was associated with the risk of any prostate cancer and advanced prostate cancer. From the current evidence, patients should be fully informed of the risk of prostate cancer before vasectomy.

Vasectomy and prostate cancer risk: a meta-analysis of prospective studies

Epidemiological cohort studies investigating the association between vasectomy and prostate cancer risk have yielded inconsistent results. The aim of the present meta-analysis is to update the evidence on the association between vasectomy and prostate cancer. A comprehensively literature search of relevant studies was performed in December 2019 using PubMed. A DerSimonian and Laird random-effects model was used to calculate the summary relative risk (RR) and its 95% confidence interval (CI). A total of 15 eligible cohort studies (16 data sets) with more than four million of participants were eventually included in this meta-analysis. There was a statistically significant higher risk of prostate cancer among men who underwent vasectomy (RR: 1.09, 95% CI: 1.04-1.13) with obvious heterogeneity among included studies (P < 0.001, I2 = 64.2%). Vasectomy was also associated with the risk of advanced prostate cancer (RR: 1.07, 95% CI: 1.02-1.13), which is less likely to be affected from detection bias. In conclusion, findings from this meta-analysis of prospective studies indicate that vasectomy may be positively associated with the risk of prostate cancer. Further large prospective studies with long follow-up are warranted to verify the findings from this meta-analysis. In addition, the potential underlying molecular mechanism needed further exploration with in vitro and animal studies.

Vasectomy and the risk of prostate cancer in a Finnish nationwide population-based cohort

INTRODUCTION & OBJECTIVES

There are conflicting reports on the association of vasectomy and the risk of prostate cancer (PCa). Our objective was to evaluate the association between vasectomy and PCa from a nationwide cohort in Finland.

MATERIALS & METHODS

Sterilization registry of Finland and the Finnish Cancer Registry data were utilized to identify all men who underwent vasectomy between years 1987-2014 in Finland. Standard incidence ratio (SIR) for PCa as well as all-cause standardized mortality ratios (SMR) were calculated.

RESULTS

We identified 38,124 men with vasectomy with a total of 429,937 person-years follow-up data. The median age at vasectomy was 39.7 years (interquartile range [IQR] 35.9-44.0), after vasectomy PCa was diagnosed in 413 men (122 cases 0-10 years, 219 cases 10-20 years and 72 cases >20 years from vasectomy). SIR for PCa for the vasectomy cohort was 1.15 (95% CI: 1.04-1.27). By the end of follow-up, 19 men had died from PCa, while the expected number was 20.5 (SMR 0.93 [95%CI: 0.56-1.44]). The overall mortality was decreased (SMR 0.54 [95%CI: 0.51-0.58]) among men with vasectomy.

CONCLUSION

We found a small statistically significant increase in PCa incidence after vasectomy, but in contrast the mortality of vasectomized men was significantly reduced. This may be due to higher likelihood of vasectomized men to undergo prostate-specific antigen testing, having healthier general lifestyle and other biological factors e.g. high reproductive fitness.

Epidemiology of Prostate Cancer

Prostate cancer is the second most frequent cancer diagnosis made in men and the fifth leading cause of death worldwide. Prostate cancer may be asymptomatic at the early stage and often has an indolent course that may require only active surveillance. Based on GLOBOCAN 2018 estimates, 1,276,106 new cases of prostate cancer were reported worldwide in 2018, with higher prevalence in the developed countries. Differences in the incidence rates worldwide reflect differences in the use of diagnostic testing. Prostate cancer incidence and mortality rates are strongly related to the age with the highest incidence being seen in elderly men (> 65 years of age). African-American men have the highest incidence rates and more aggressive type of prostate cancer compared to White men. There is no evidence yet on how to prevent prostate cancer; however, it is possible to lower the risk by limiting high-fat foods, increasing the intake of vegetables and fruits and performing more exercise. Screening is highly recommended at age 45 for men with familial history and African-American men. Up-to-date statistics on prostate cancer occurrence and outcomes along with a better understanding of the etiology and causative risk factors are essential for the primary prevention of this disease.

Vasectomy and the risk of prostate cancer in a prospective US Cohort: Data from the NIH-AARP Diet and Health Study

BACKGROUND

Several studies have linked vasectomy with the risk of prostate cancer; however, this association has been attributed to selection bias. Since vasectomy is a common and effective form of contraception, these implications are significant. Therefore, we sought to test this association in a large observational cohort.

OBJECTIVE

To evaluate the potential association between prior vasectomy and the risk of developing prostate cancer.

MATERIALS AND METHODS

We evaluated the relationship between vasectomy and prostate cancer in the NIH-AARP Diet and Health Study. Of the 111,914 men, prostate cancer was identified in 13,885 men and vasectomies were performed in 48,657. We used multivariate analysis to examine the relationship between prostate cancer and vasectomy. We also performed propensity score-adjusted and propensity score-matched analysis.

RESULTS

Men utilizing vasectomy were more likely to be ever married, fathers, educated, white, and screened for prostate cancer. During 4,251,863 person-years of follow-up, there was a small association between vasectomy and incident prostate cancer with a hazard ratio of 1.05 (95% CI, 1.01-1.11). However, no significant association was found when looking separately at prostate cancer by grade or stage. Conclusions were similar when using propensity adjustment and matching. Importantly, a significant interaction between vasectomy and PSA screening was identified.

DISCUSSION

Estimates of the association between vasectomy and prostate cancer are sensitive to analytic method underscoring the tenuous nature of the connection. Given the differences between men who do and do not utilize vasectomy, selection bias appears likely to explain any identified association between vasectomy and prostate cancer.

CONCLUSIONS

With over 20 years of follow-up, no convincing relationship between vasectomy and prostate cancer of any grade was identified.

Association between vasectomy and risk of testicular cancer: A systematic review and meta-analysis

Objectives

A number of researchers have reported that vasectomy is a risk factor for testicular cancer. However, this conclusion is inconsistent with a number of other published articles. Hence, we conducted this meta-analysis to assess whether vasectomy increases the risk of testicular cancer.

Materials and methods

We identified all related studies by searching the PubMed, Embase, and Cochrane Library database from January 01, 1980 to June 01, 2017. The Newcastle-Ottawa Scale (NOS) checklist was used to assess all included non-randomized studies. Summarized odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the difference in outcomes between case and control groups. Subgroup analyses were performed according to the study design and country.

Results

A total of eight studies (2176 testicular cancer patients) were included in this systematic review and meta-analysis. Six articles were case-control studies, and two were cohort studies. The pooled estimate of the OR was 1.10 (95% CI: 0.93–1.30) based on the eight studies in a fixed effects model. Two subgroup analyses were performed according to the study design and country. The results were consistent with the overall findings. Publication bias was detected by Begg’s test and Egger’s test and p values > 0.05, respectively.

Conclusions

Our meta-analysis suggested that there was no association between vasectomy and the development of testicular cancer. More high-quality studies are warranted to further explore the association between vasectomy and risk of testicular cancer.

The Association Between Vasectomy and Prostate Cancer: A Systematic Review and Meta-analysis

Importance

Despite 3 decades of study, there remains ongoing debate regarding whether vasectomy is associated with prostate cancer.

Objective

To determine if vasectomy is associated with prostate cancer.

Data Sources

The MEDLINE, EMBASE, Web of Science, and Scopus databases were searched for studies indexed from database inception to March 21, 2017, without language restriction.

Study Selection

Cohort, case-control, and cross-sectional studies reporting relative effect estimates for the association between vasectomy and prostate cancer were included.

Data Extraction and Synthesis

Two investigators performed study selection independently. Data were pooled separately by study design type using random-effects models. The Newcastle-Ottawa Scale was used to assess risk of bias.

Main Outcomes and Measures

The primary outcome was any diagnosis of prostate cancer. Secondary outcomes were high-grade, advanced, and fatal prostate cancer.

Results

Fifty-three studies (16 cohort studies including 2 563 519 participants, 33 case-control studies including 44 536 participants, and 4 cross-sectional studies including 12 098 221 participants) were included. Of these, 7 cohort studies (44%), 26 case-control studies (79%), and all 4 cross-sectional studies were deemed to have a moderate to high risk of bias. Among studies deemed to have a low risk of bias, a weak association was found among cohort studies (7 studies; adjusted rate ratio, 1.05; 95% CI, 1.02-1.09; P < .001; I2 = 9%) and a similar but nonsignificant association was found among case-control studies (6 studies; adjusted odds ratio, 1.06; 95% CI, 0.88-1.29; P = .54; I2 = 37%). Effect estimates were further from the null when studies with a moderate to high risk of bias were included. Associations between vasectomy and high-grade prostate cancer (6 studies; adjusted rate ratio, 1.03; 95% CI, 0.89-1.21; P = .67; I2 = 55%), advanced prostate cancer (6 studies; adjusted rate ratio, 1.08; 95% CI, 0.98-1.20; P = .11; I2 = 18%), and fatal prostate cancer (5 studies; adjusted rate ratio, 1.02; 95% CI, 0.92-1.14; P = .68; I2 = 26%) were not significant (all cohort studies). Based on these data, a 0.6% (95% CI, 0.3%-1.2%) absolute increase in lifetime risk of prostate cancer associated with vasectomy and a population-attributable fraction of 0.5% (95% CI, 0.2%-0.9%) were calculated.

Conclusions and Relevance

This review found no association between vasectomy and high-grade, advanced-stage, or fatal prostate cancer. There was a weak association between vasectomy and any prostate cancer that was closer to the null with increasingly robust study design. This association is unlikely to be causal and should not preclude the use of vasectomy as a long-term contraceptive option.

Vasectomy and Risk of Prostate Cancer in a Screening Trial

Background: Vasectomy has been implicated as a risk factor for prostate cancer in multiple epidemiologic studies over the past 25 years. Whether this relationship is causal remains unclear. This study examines the association between vasectomy and prostate cancer in the Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial, which randomized men to usual care or annual prostate cancer screening.Methods: We performed a retrospective analysis of 13-year screening and outcomes data from the PLCO trial. Multivariable Cox proportional hazards regression stratified by study arm and age at vasectomy was performed.Results: There was an increased risk of prostate cancer in men who had undergone a vasectomy and were randomized to the usual care arm of the study (adjusted HR, 1.11; 95% confidence interval, 1.03-1.20; P = 0.008). There was no association between vasectomy and diagnosis of prostate cancer in men randomized to the prostate cancer screening arm. Only men undergoing vasectomy at an older age in the usual care arm of the study, but not the prostate cancer screening arm, were at increased risk of being diagnosed with prostate cancer.Conclusions: Vasectomy was not associated with prostate cancer risk among men who were screened for prostate cancer as part of a clinical trial, but was associated with prostate cancer detection in men receiving usual care.Impact: The positive association between vasectomy and prostate cancer is likely related to increased detection of prostate cancer based on patterns of care rather than a biological effect of vasectomy on prostate cancer development. Cancer Epidemiol Biomarkers Prev; 26(11); 1653-9. ©2017 AACR.

Vasectomy and Prostate Cancer Risk in the European Prospective Investigation Into Cancer and Nutrition (EPIC)

Purpose Vasectomy is a commonly used form of male sterilization, and some studies have suggested that it may be associated with an increased risk of prostate cancer, including more aggressive forms of the disease. We investigated the prospective association of vasectomy with prostate cancer in a large European cohort, with a focus on high-grade and advanced-stage tumors, and death due to prostate cancer. Patients and Methods A total of 84,753 men from the European Prospective Investigation into Cancer and Nutrition (EPIC), aged 35 to 79 years, provided information on vasectomy status (15% with vasectomy) at recruitment and were followed for incidence of prostate cancer and death. We estimated the association of vasectomy with prostate cancer risk overall, by tumor subtype, and for death due to prostate cancer, using multivariable-adjusted Cox proportional hazards models. Results During an average follow-up of 15.4 years, 4,377 men were diagnosed with prostate cancer, including 641 who had undergone a vasectomy. Vasectomy was not associated with prostate cancer risk (hazard ratio [HR], 1.05; 95% CI, 0.96 to 1.15), and no evidence for heterogeneity in the association was observed by stage of disease or years since vasectomy. There was some evidence of heterogeneity by tumor grade ( P = .02), with an increased risk for low-intermediate grade (HR, 1.14; 95% CI, 1.01 to 1.29) but not high-grade prostate cancer (HR, 0.83; 95% CI, 0.64 to 1.07). Vasectomy was not associated with death due to prostate cancer (HR, 0.88; 95% CI, 0.68 to 1.12). Conclusion These findings from a large European prospective study show no elevated risk for overall, high-grade or advanced-stage prostate cancer, or death due to prostate cancer in men who have undergone a vasectomy compared with men who have not.

Vasectomy and risk of prostate cancer: population based matched cohort study

OBJECTIVE

 To determine the association between vasectomy and prostate cancer, adjusting for measures of health seeking behaviour.

DESIGN

 Population based matched cohort study.

SETTING

 Multiple validated healthcare databases in Ontario, Canada, 1994-2012.

PARTICIPANTS

 326 607 men aged 20 to 65 who had undergone vasectomy were identified through physician billing codes and matched 1:1 on age (within two years), year of cohort entry, comorbidity score, and geographical region to men who did not undergo a vasectomy.

MAIN OUTCOMES MEASURES

 The primary outcome was incident prostate cancer. Secondary outcomes were prostate cancer related grade, stage, and mortality.

RESULTS

 3462 incident cases of prostate cancer were identified after a median follow-up of 10.9 years: 1843 (53.2%) in the vasectomy group and 1619 (46.8%) in the non-vasectomy group. In unadjusted analysis, vasectomy was associated with a slightly increased risk of incident prostate cancer (hazard ratio 1.13, 95% confidence interval 1.05 to 1.20). After adjustment for measures of health seeking behaviour, however, no association remained (adjusted hazard ratio 1.02, 95% confidence interval 0.95 to 1.09). Moreover, no association was found between vasectomy and high grade prostate cancer (adjusted odds ratio 1.05, 95% confidence interval 0.67 to 1.66), advanced stage prostate cancer (adjusted odds ratio 1.04, 0.81 to 1.34), or mortality (adjusted hazard ratio 1.06, 0.60 to 1.85).

CONCLUSION

 The findings do not support an independent association between vasectomy and prostate cancer.

Vasectomy and prostate cancer risk: a historical synopsis of undulating false causality

The potential influence of vasectomy being a risk factor for the development of prostate cancer is not a new concept, with more than 30 publications addressing the topic. Given the global frequency of vasectomy and the prevalence of prostate cancer, this subject justifiably deserves scrutiny. Several articles have claimed that vasectomy puts men at risk for future development of prostate cancer. We explore articles that have shown the contrary (no link), explore the studies’ strengths and weaknesses, describe possible prostate cancer pathophysiologic mechanisms, and apply Bradford Hill criteria to help discern correlation with causation. The risk and interest of association of prostate cancer with vasectomy has waxed and waned over the last three decades. Based on our review, vasectomy remains a safe form of sterilization and does not increase prostate cancer risk.

Vasectomy: potential links to an increased risk of aggressive prostate cancer?

Several studies have found associations between aggressive prostate cancer (PC) and having a vasectomy. However, findings from two very recent meta-analyses have found that this is not the case. Therefore, the data are mixed. Herein, we detail the controversy between vasectomy and PC risk, particularly aggressive PC, by shedding some light on the molecular pathways, potential risk factors and suggested links for those considering vasectomy and medical professionals who perform it. We conclude by supporting the American Urological Association's position that there is no need to discuss potential prostate cancer risks with patients considering vasectomy given reasonably strong data finding no link between vasectomy and prostate cancer risk.

Vasectomy and risk of aggressive prostate cancer: a 24-year follow-up study

PURPOSE

Conflicting reports remain regarding the association between vasectomy, a common form of male contraception in the United States, and prostate cancer risk. We examined prospectively this association with extended follow-up and an emphasis on advanced and lethal disease.

PATIENTS AND METHODS

Among 49,405 U.S. men in the Health Professionals Follow-Up Study, age 40 to 75 years at baseline in 1986, 6,023 patients with prostate cancer were diagnosed during the follow-up to 2010, including 811 lethal cases. In total, 12,321 men (25%) had vasectomies. We used Cox proportional hazards models to estimate the relative risk (RR) and 95% CIs of total, advanced, high-grade, and lethal disease, with adjustment for a variety of possible confounders.

RESULTS

Vasectomy was associated with a small increased risk of prostate cancer overall (RR, 1.10; 95% CI, 1.04 to 1.17). Risk was elevated for high-grade (Gleason score 8 to 10; RR, 1.22; 95% CI, 1.03 to 1.45) and lethal disease (death or distant metastasis; RR, 1.19; 95% CI, 1.00 to 1.43). Among a subcohort of men receiving regular prostate-specific antigen screening, the association with lethal cancer was stronger (RR, 1.56; 95% CI, 1.03 to 2.36). Vasectomy was not associated with the risk of low-grade or localized disease. Additional analyses suggested that the associations were not driven by differences in sex hormone levels, sexually transmitted infections, or cancer treatment.

CONCLUSION

Our data support the hypothesis that vasectomy is associated with a modest increased incidence of lethal prostate cancer. The results do not appear to be due to detection bias, and confounding by infections or cancer treatment is unlikely.

Vasectomy occlusion techniques for male sterilization

BACKGROUND

Vasectomy is an increasingly popular and effective family planning method. A variety of vasectomy techniques are used worldwide, including vas occlusion techniques (excision and ligation, thermal or electrocautery, and mechanical and chemical occlusion methods), as well as vasectomy with vas irrigation or with fascial interposition. Vasectomy guidelines largely rely on information from observational studies. Ideally, the choice of vasectomy techniques should be based on the evidence from randomized controlled trials (RCTs).

OBJECTIVES

The objective of this review was to compare the effectiveness, safety, acceptability and costs of vasectomy techniques for male sterilization.

SEARCH METHODS

In February 2014, we updated the searches of CENTRAL, MEDLINE, POPLINE and LILACS. We looked for recent clinical trials in ClinicalTrials.gov and the International Clinical Trials Registry Platform. Previous searches also included EMBASE. For the initial review, we searched the reference lists of relevant articles and book chapters.

SELECTION CRITERIA

We included RCTs comparing vasectomy techniques, which could include suture ligature, surgical clips, thermal or electrocautery, chemical occlusion, vas plugs, vas excision, open-ended vas, fascial interposition, or vas irrigation.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts located in the literature searches. Two reviewers independently extracted data from articles identified for inclusion. Outcome measures include contraceptive efficacy, safety, discontinuation, and acceptability. Peto odds ratios (OR) with 95% confidence intervals (CI) were used for dichotomous outcomes, such as azoospermia. The mean difference (MD) was used for the continuous variable of operating time.

MAIN RESULTS

Six studies met the inclusion criteria. One trial compared vas occlusion with clips versus a conventional vasectomy technique. No difference was found in failure to reach azoospermia (no sperm detected). Three trials examined vasectomy with vas irrigation. Two studies looked at irrigation with water versus no irrigation, while one examined irrigation with water versus the spermicide euflavine. None found a difference between the groups for time to azoospermia. However, one trial reported that the median number of ejaculations to azoospermia was lower in the euflavine group compared to the water irrigation group. One high-quality trial compared vasectomy with fascial interposition versus vasectomy without fascial interposition. The fascial interposition group was less likely to have vasectomy failure. Fascial interposition had more surgical difficulties, but the groups were similar in side effects. Lastly, one trial found that an intra-vas was less likely to produce azoospermia than was no-scalpel vasectomy. More men were satisfied with the intra-vas device, however.

AUTHORS' CONCLUSIONS

For vas occlusion with clips or vasectomy with vas irrigation, no conclusions can be made as those studies were of low quality and underpowered. Fascial interposition reduced vasectomy failure. An intra-vas device was less effective in reducing sperm count than was no-scalpel vasectomy. RCTs examining other vasectomy techniques were not available. More and better quality research is needed to examine vasectomy techniques.

[Non dietetic environmental risk factors in prostate cancer]

INTRODUCTION

The aim is to update and disclose the main environmental risk factors, excluding dietary factors, involved in the etiopathology of prostate cancer.

MATERIALS AND METHOD

Bibliographic review of the last 25 years of non-dietary environmental risk factors associated with prostate cancer between 1985 and 2010, obtained from MedLine, CancerLit, Science Citation Index and Embase. The search profiles were Environmental Risk Factors/Tobacco/Infectious-Inflammatory Factors/Pesticides/Vasectomy/Occupational Exposures/Chemoprevention Agents/Radiation and Prostate Cancer.

RESULTS

While some non-dietary environmental risk factors increase the risk of acquiring the disease, others decrease it. Of the former, it is worth mentioning exposal to tobacco smoke, chronic infectious-inflammatory prostatic processes and occupational exposure to cadmium, herbicides and pesticides. The first factors that reduce the risk are the use of chemopreventive drugs (Finasterida, Dutasteride) and exposure to ultraviolet solar radiation. With the current data, a vasectomy does not influence the risk of developing the disease.

CONCLUSIONS

The slow process of prostate carcinogenesis is the final result of the interaction of constitutional risk and environmental factors. Non-dietary environmental factors play an important role in the etiopathology of this disease. To appropriately assess the risk factors, extensive case studies that include all the possible variables must be analysed.

Medical history, body size, and cigarette smoking in relation to fatal prostate cancer

OBJECTIVES

Prostate cancer has few known risk factors. As part of a population-based case-control study conducted in four health maintenance organizations, the authors examined the associations between fatal prostate cancer and several medical and behavioral characteristics.

METHODS

Cases were 768 health plan members who died of prostate adenocarcinoma during the period 1997-2001. We randomly selected controls (929) from the health plan membership and matched them to cases on health plan, age, race, and pattern of health plan membership. We examined medical records to obtain information on potential risk factors during the 10 years before the date on which prostate cancer was first suspected; the same reference date was used for the matched controls.

RESULTS

Anthropometric characteristics, as well as personal histories of benign prostatic hypertrophy, transurethral prostatectomy, cancer, diabetes, prostatitis, hypertension, and vasectomy were largely similar for cases and controls. Men who died from prostate cancer were more likely than controls to have been cigarette smokers according to the most recent smoking notation before the reference date (odds ratio 1.5, 95% confidence interval 1.1-2.0).

CONCLUSIONS

The observed increase in risk associated with recent cigarette smoking is consistent with the findings of several other studies. However, in contrast with some reports, we observed no connection between fatal prostate cancer and some prior health conditions or measures of body size.

Putative health risks associated with vasectomy

Vasectomy is widely regarded as a safe method of contraception, but over the years there have been many reports suggesting putative health risks associated with the procedure. Concerns over the possible association of vasectomy with a number of medical conditions, including cardiovascular disease, testicular cancer, prostate cancer, psychologic distress, and a variety of immune complex-mediated disease processes have been reported. Most recently, a manuscript from the neurology literature has described an association between vasectomy and primary progressive aphasia, a rare variety of frontotemporal dementia. This article reviews the literature surrounding each of these purported health concerns. Because the ultimate findings have important ramifications for both informed consent of vasectomy patients and for public health, the reported health risks in question should be critically evaluated.

Prostate cancer and vasectomy: a hospital-based case-control study in China, Nepal and the Republic of Korea

BACKGROUND

The study of a possible relationship between vasectomy and prostate cancer has yielded mixed results. Data from developing countries are limited.

STUDY DESIGN

We conducted a hospital-based case-control study in China, Nepal and the Republic of Korea to evaluate the risk of prostate cancer after vasectomy.

RESULTS

Prostate cancer in 294 cases (confirmed by independent pathologists) and 879 matched controls were included. The odds ratio of prostate cancer in men with a history of vasectomy was 1.21 [95% confidence interval (95% CI)=0.79, 1.87]. No significant trend was observed in risk by time since vasectomy or age at vasectomy. The odds ratio for localized disease was 1.02 (95% CI=0.53, 1.95); the odds ratio for later stages was 1.41 (95% CI=0.78, 2.53). No confounding factor was identified. The study illustrated differential misclassification of disease by vasectomy status; reference pathologists determined that 28% of men with a history of vasectomy, compared with 17% of men without a history of vasectomy, were misdiagnosed with prostate cancer by local pathologists.

CONCLUSION

Vasectomy is not associated with an increased risk of prostate cancer in developing countries where the rate of the disease is low.

Vasectomy and the risk of prostate cancer

PURPOSE

While the weight of evidence shows no association overall between vasectomy and prostate cancer, there has been some suggestion that an association may exist in subgroups, such as men who have a family history of prostate cancer, men who undergo vasectomy at a younger age or when several decades have passed since the procedure. Studies of risk with long latency periods have been hampered by small sample sizes in subgroups since vasectomy only became widely used in the 1960s and generally prostate cancer has a long latency period.

MATERIALS AND METHODS

We analyzed data from a recent population based case-control study that was designed specifically to address this issue of risk in subgroups. Interviews were completed with 1,001 men diagnosed with prostate cancer from January 1, 2002 through December 31, 2005 in the Seattle-Puget Sound region and in 942 matched control men. Subjects were black and white men between the ages of 35 and 74 years. Data were analyzed using unconditional logistic regression to calculate the OR as an estimate of the relative risk of prostate cancer associated with various vasectomy parameters.

RESULTS

The prevalence of vasectomy was similar in cases and controls (36.2% and 36.1%, respectively, adjusted OR 1.0, 95% CI 0.8-1.2). There were also no associations between prostate cancer and age at vasectomy, years elapsed since vasectomy or calendar year of vasectomy.

CONCLUSIONS

These findings indicate that there is no association between vasectomy and the risk of prostate cancer.

Ethnic differences in prostate cancer survival in New Zealand: a national study

OBJECTIVE

To examine disease-specific survival from prostate cancer by ethnic group in New Zealand.

METHODS

Analyses were based on the 7,733 men with histologically confirmed prostate cancer diagnosed from the start of 1996 to the end of 1999 in New Zealand. Five-year adjusted prostate-specific mortality rates and hazard ratios were calculated for Maori, Pacific, and European men.

RESULTS

In univariate analyses, Maori and Pacific men had higher mortality particularly in the first year after a diagnosis of prostate cancer than did European men. The strongest prognostic factors for prostate cancer were Gleason score and age. When survival analyses by ethnic group were adjusted for age and Gleason score the disparities in survival for Maori men and Pacific men with low-grade prostate cancers remained, with European men having the best survival.

CONCLUSIONS

Several possible explanations have been proposed to explain the survival disparities by ethnicity in New Zealand. Differentials in Gleason grade of disease by ethnic group explain a lot of these disparities. Further data on stage of disease at diagnosis, co-morbidity, treatment, access to health services, and behavioral and environmental factors are needed to resolve these issues.

Hypercholesterolemia and prostate cancer: a hospital-based case-control study

OBJECTIVE

High levels of serum cholesterol have been proposed to increase the risk of prostate cancer but the epidemiologic evidence is limited.

METHODS

We conducted a hospital-based case-control study in Fargo, ND, USA, to examine the association between hypercholesterolemia and prostate cancer. Cases were men with incident, histologically confirmed prostate cancer. Controls were men without clinical cancer who were seen at the same hospital for an annual physical exam. Demographic and clinical data were abstracted from patients' medical charts.

RESULTS

From a patient population aged 50 to 74 years old, we obtained data on 312 White cases and 319 White controls. Hypercholesterolemia was defined as total cholesterol greater than 5.17 (mmol/l). Univariate logistic regression showed a significant association between hypercholesterolemia and prostate cancer (odds ratio (OR) = 1.64, 95% confidence interval (CI): 1.19-2.27). This association changed only slightly after adjustment for age, family history of prostate cancer, body mass index, type 2 diabetes, smoking, and multivitamin use (OR = 1.58, 95% CI: 1.11-2.24). A significant association was found between low HDL and prostate cancer (OR = 1.57, 95% CI: 1.04-2.36). High LDL was associated with a 60% increased risk for prostate cancer (OR = 1.60, 95% CI: 1.09-2.34). Compared to never smokers, current smokers had an 84% increased risk for prostate cancer (OR = 1.84, 95% CI: 1.09-3.13).

CONCLUSION

This study adds to recent evidence that hypercholesterolemia may increase the risk of prostate cancer in white men.

Advances in male contraception

Despite significant advances in contraceptive options for women over the last 50 yr, world population continues to grow rapidly. Scientists and activists alike point to the devastating environmental impacts that population pressures have caused, including global warming from the developed world and hunger and disease in less developed areas. Moreover, almost half of all pregnancies are still unwanted or unplanned. Clearly, there is a need for expanded, reversible, contraceptive options. Multicultural surveys demonstrate the willingness of men to participate in contraception and their female partners to trust them to do so. Notwithstanding their paucity of options, male methods including vasectomy and condoms account for almost one third of contraceptive use in the United States and other countries. Recent international clinical research efforts have demonstrated high efficacy rates (90-95%) for hormonally based male contraceptives. Current barriers to expanded use include limited delivery methods and perceived regulatory obstacles, which stymie introduction to the marketplace. However, advances in oral and injectable androgen delivery are cause for optimism that these hurdles may be overcome. Nonhormonal methods, such as compounds that target sperm motility, are attractive in their theoretical promise of specificity for the reproductive tract. Gene and protein array technologies continue to identify potential targets for this approach. Such nonhormonal agents will likely reach clinical trials in the near future. Great strides have been made in understanding male reproductive physiology; the combined efforts of scientists, clinicians, industry and governmental funding agencies could make an effective, reversible, male contraceptive an option for family planning over the next decade.

PSA testing and digital rectal examination in New Zealand

OBJECTIVE

To investigate the use of digital rectal examination and prostate specific antigen (PSA) testing in a population-based sample of men in New Zealand.

METHODS

A random selection of men aged 40-74 years, weighted by age, was chosen from the general electoral roll of New Zealand. Only men with a telephone who had been married at some time were eligible. Telephone interviews were conducted using a standard questionnaire. Crude and age-adjusted proportions were calculated. Logistic regression was used to explore associations between sociodemographic factors and digital rectal examination or PSA testing.

RESULTS

Interviews were completed for 85% of the 1,486 eligible men and analyses were confined to the 1,225 European men. Many more men reported having a digital rectal examination (41%; 95% CI 33.8-48.2) than a PSA test (9%; 95% CI 4.2-14.2). Men in the lowest social class were significantly less likely to have had a digital rectal examination (OR 0.30; 95% CI 0.18-0.50) or PSA test (OR 0.25; 95% CI 0.11-0.60) compared with those in the highest social class. Men with vocational training or no post-school qualifications were approximately half as likely to report a digital rectal examination or a PSA test compared with men with degrees or diplomas.

CONCLUSIONS

Although current New Zealand recommendations are that population screening for prostate cancer should not be introduced, many men are still having digital rectal examinations and PSA tests in the absence of symptoms. The frequency of PSA testing is considerably lower than in Australia and appears to be largely influenced by a man's social class.

Vasectomy occlusion techniques for male sterilization

BACKGROUND

Vasectomy is an increasingly popular and effective family planning method. A variety of vasectomy techniques are used worldwide, including various vas occlusion techniques (excision and ligation, thermal or electrocautery, and mechanical and chemical occlusion methods), as well as vasectomy with vas irrigation or with fascial interposition. Vasectomy guidelines largely rely on information from observational studies. Ideally, the choice of vasectomy techniques should be based on the best available evidence from randomized controlled trials.

OBJECTIVES

The objective of this review was to compare the effectiveness, safety, acceptability and costs of vasectomy techniques for male sterilization.

SEARCH STRATEGY

We searched the computerized databases of CENTRAL, MEDLINE, EMBASE, POPLINE and LILACS. In addition, we searched the reference lists of relevant articles and book chapters.

SELECTION CRITERIA

We included randomized controlled trials comparing vasectomy techniques.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts located in the literature searches. Two reviewers independently extracted data from articles identified for inclusion. Outcome measures include contraceptive efficacy, safety, discontinuation, and acceptability.

MAIN RESULTS

Six studies met the inclusion criteria. One trial compared vas occlusion with clips versus a conventional vasectomy technique. No difference was found in failure to reach azoospermia. Three trials examined vasectomy with vas irrigation. Two studies looked at irrigation with water versus no irrigation, while one examined irrigation with water versus the spermicide euflavine. None found a difference between the groups for time to azoospermia. However, one trial reported that the median number of ejaculations to azoospermia was lower in the euflavine group compared to the water irrigation group. One high-quality trial compared vasectomy with fascial interposition versus vasectomy without fascial interposition. The fascial interposition group was less likely to have vasectomy failure. Fascial interposition had more surgical difficulties, but the groups were similar in side effects. Lastly, one trial found that an intra-vas was less likely to produce azoospermia than was no-scalpel vasectomy. More men were satisfied with the intra-vas device, however.

AUTHORS' CONCLUSIONS

For vas occlusion with clips or vasectomy with vas irrigation, no conclusions can be made as those studies were of low quality and underpowered. Fascial interposition reduced vasectomy failure. An intra-vas device was less effective in reducing sperm count than was no-scalpel vasectomy. Randomized controlled trials examining other vasectomy techniques were not available. More and better quality research is needed to examine vasectomy techniques.

Risk factors for prostate cancer: A national case-control study

Statutory notification of cancer in New Zealand provided an opportunity to investigate risk factors for prostate cancer in a large national population-based case-control study. We analyzed data obtained from telephone interviews with 923 cases and 1,224 controls. For inclusion in the study, all subjects had to have been married at some time. We found an increased risk of prostate cancer among those with a history of prostate cancer in first degree relatives (RR 2.6; 95% CI, 1.9-3.7) and an increased risk of prostate cancer with length of marriage among men married only once and still married at interview. For a consecutive subgroup of 550 cases and 819 controls, data on height and weight at age 20 and at 5 years before interview were collected. Men less than or equal to 1.7 m in height at age 20 years had a lower risk of prostate cancer than men taller at that age. There was no association between weight or body mass index and risk of prostate cancer.

Evidence based contraceptive choices

People who attend for contraceptive advice have usually formulated an idea of the type of contraceptive that will suit them best. They may wish to use a method that is long, short or medium acting. These are defined as follows: Long-acting method requires renewal no more frequently than every 3 months (e.g. injectable or intrauterine). Short-acting method used daily or with every act of intercourse (e.g. pills, condoms) Medium-acting method requires renewal weekly or monthly (e.g. ring, patch). For men the choice is limited to condoms or vasectomy. Some women do not wish to use hormonal preparations or have an intrauterine device (IUD) or implant inserted. There may also be cultural influences making certain methods of contraception unacceptable. Each of these factors influences the final decision of which method of contraception is decided upon. In addition to taking a full medical and sexual history to identify any risks to the individual's health, which might be increased by a particular contraceptive, time must be spent discussing the options available. It is important to ensure that there is a full understanding of the advantages and disadvantages of each method. The most successful contraceptive method is likely to be the one that the woman (or man) chooses, rather than the one the clinician chooses for them. Access for women to contraception can be improved by having convenient clinic times and service developments such as nurse prescribing and Patient Group Directions.

Association of Vasectomy and Prostate Cancer Among Men in a Maryland Cohort

OBJECTIVES

To evaluate the association of vasectomy with prostate cancer.

METHODS

Participants were male members of the CLUE II cohort followed since 1989. On a questionnaire mailed in 1996, the men were asked if they had had a vasectomy and their age at vasectomy. Between 1996 and April 2004, 78 prostate cancer cases were confirmed among the 3373 men who were at least 35 years old at baseline and who completed the questions about vasectomy. Cox proportional hazards regression was used to estimate age-adjusted hazard ratios (HR) of prostate cancer.

RESULTS

The HR for prostate cancer for men who had had a vasectomy was 2.03 (95% CI: 1.24-3.32). Risk of low-grade disease (HR=2.87; 95% CI 1.49-5.54), but not high-grade disease (HR=0.99; 95% CI 0.36-2.76), was higher in men who had had a vasectomy. No statistically significant associations were observed for low- or high-stage disease. The association for vasectomy was more pronounced in men who were 40 years at the time of vasectomy (HR=2.63; 95% CI 1.40-4.94) than in men who were younger at vasectomy.

CONCLUSIONS

The results from this prospective study suggest a positive association between vasectomy and prostate cancer, especially low-grade disease.

Cancer and cardiovascular disease after vasectomy: an epidemiological database study

OBJECTIVE

To determine whether vasectomy is associated with an increased long-term risk of cancer or cardiovascular disease.

DESIGN

Analysis of database of linked statistical records of hospital admissions and deaths.

SETTING

Health region in southern England.

PATIENT(S)

Men aged 20-59 years who were admitted to a hospital for vasectomy.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Rates of cancer and cardiovascular disease compared with the corresponding rates in a reference cohort, expressed as a rate ratio.

RESULT(S)

We found no elevation of risk, after vasectomy, of prostate cancer (rate ratio 0.74, 95% confidence interval [CI] 0.45-1.14) or other cancers. The rate ratio for coronary heart disease overall after vasectomy was 0.95 (95% CI 0.88-1.02); and the rate ratio > or =20 years after vasectomy was 0.98 (95% CI 0.80-1.19).

CONCLUSION(S)

Our findings add to the evidence that vasectomy is not associated with an increase in the long-term risk of these diseases.

Adenocarcinoma of the prostate: epidemiological trends, screening, diagnosis, and surgical management of localized disease

Prostate cancer is a leading cause of mortality and morbidity worldwide. Despite years of study and effort, certain key questions remain unanswered, including how prostate cancer is best detected and diagnosed, how it is best treated, and how best to minimize the complications of treatment. The aim of this article is to briefly address these topics to shed light on the current best practices in prostate cancer screening, diagnosis, and surgical treatment of localized disease. We examine current trends in prostate cancer epidemiology and screening, including genetic and dietary risk factors and the newer prostate-specific antigen-derived screening modalities. Methods of diagnosis, including an overview of prostate biopsy technique and indications, and a brief review of relevant pathologic findings are provided. An in-depth analysis of traditional prostate cancer surgical management highlights the relevant advantages and disadvantages of radical retropubic and perineal prostatectomy. Complications of surgery, prognostic factors, and the many risk prediction models currently available are discussed. In all, this article aims to give the reader a broad overview of the basic elements of prostate cancer diagnosis and surgical treatment in the modem era.

Sexually transmitted diseases and other urogenital conditions as risk factors for prostate cancer: a case–control study in Wayne County, Michigan

OBJECTIVE To investigate associations between prostate cancer and sexually transmitted diseases (STDs), prostatitis, benign prostatic hyperplasia (BPH), and vasectomy in a population-based case-control study in Wayne County, Michigan, among African American and white men aged 50--74 years.

METHODS

Incident prostate cancer cases (n=700) from 1996--1998 were identified from the Metropolitan Detroit Cancer Surveillance System. Controls (n=604) were identified through random digit dialing and Medicare recipient lists, and frequency matched to cases on age and race. History of potential prostate cancer risk factors was ascertained through in-person interview.

RESULTS

Prostate cancer was not associated with STD or vasectomy history. History of prostatitis was associated with prostate cancer among all subjects (odds ratio [OR]=1.8, 95% confidence interval [CI]: 1.1, 2.9) and in African American men (OR=2.2, 95% CI: 1.1, 4.6). History of BPH was associated with prostate cancer among all subjects (OR=2.4, 95% CI: 1.8, 3.3); significant associations were observed in both African American (OR=2.7, 95% CI: 1.6, 4.4) and white (OR=2.3, 95% CI: 1.5, 3.4) men.

CONCLUSIONS

Among all subjects, prostate cancer was associated with prostatitis and BPH history, but not with STD or vasectomy history. Prevention efforts could be enhanced if inflammatory or infectious etiologies are found to be of importance in the subsequent development of prostate cancer.

[Vasectomy: study of 300 interventions. Review of the national literature and of its complications]

OBJECTIVES

The aims of this paper are: 1. To study the demand and reasons why of the vasectomy in area 12 of Valencian Community. 2. To analyse the adverse effects of our series and the predictable risk factors. 3. To review the adverse effects in the national series. 4. To review the adverse effects referred to in international publications.

PATIENTS AND METHODS

A retrospective study was made of 300 patients who had submitted themselves to a vasectomy between january 1992 and december 2000. All the clinical dossiers were reviewed according to 10 pre-established variables. age, number of offspring, reasons why, pre-vasectomy anticontraceptives; date of operation, type of anaesthesia used, pathologic anatomy, semen analysis after vasectomy, adverse effects and their possible causes (risk factors). The basic statistic study was done using a data base of Microsoft Access and the interpretations of the different variables using a table of Excel.

RESULTS

The demand for contraceptive attention (vasectomy) is the 8th cause for external urological consulting and the 4th for urological local ambulatory surgery of our area. 300 operations were done during that period. The average age of the patients was 37.5 years old (ranging from 25 to 51). The number of offspring ranged from 1 to 7, with a promedia of 2.41 children/patient. The reasons why were: voluntary family planning (86%), medical illnesses of the female which contraindicated gestation (9%), genetic reasons (4.33%) and social-sanitary problems (0.66%). Contraceptive methods used by 71.63% are known: The widest-used method being IUD (49.74%) and the preservative (25.88%). 30 patients (10%) had adverse effects, 29 patients having light adverse effects. The most frequent were: 12 orchiepididymitis (4%), 5 spermatic granulomas (1.66%), 3 chronic scrotal pain (1%), 2 scrotal haematoma (0.66%) and 2 bleeding (0.66%). There was one serious complications and of all the cases mentioned above only one needed hospitalization (impetigo-sepsis) and another needed surgery due to a spermatic granuloma. There were no pregnancies or post-vasectomy court cases. 81% of the patients had been declared azoospermic within 45 to 60 days after the vasectomy in one or two consecutive semen analysis.

CONCLUSIONS

The vasectomy is a safe and simple way for male sterilization. It's the most widely done urologic operation in Spain. The technique isn't extent of adverse effects (0 to 18%) and its seriousness varies from a simple ecchymosis to Fournier's gangrene, endocarditis or sepsis. A doctor would be considered negligent if he/she didn't inform the patient about the remote possibility of a spontaneous recanalisation of the vas deferens leading to renewed fertility (failure of the vasectomy). It is imperative to give post-vasectomy information where the patient must continue using his habitual anticonceptive method until the azoospermia shown in 2 semen analysis confirm the sterility of the patient so that the urologist has no legal problem.

A polymeric mini-stent designed to facilitate the vasectomy reversal operation. A rabbit model study

Vasectomy has become popular since it is the safest surgical method for contraception. It is known that approximately 6% of the men that undergo vasectomy will seek reversal (vasovasostomy). This operation is, however, technically demanding and relatively time-consuming. This study was based on the hypothesis that a polymeric mini-stent can facilitate and accelerate vasovasostomies. A mini-stent was manufactured out of a crosslinked hydrogel biomaterial, which was synthesized from N-vinyl-pyrrolidinone (NVP), n-butylmethacrylate, and (triethyleneglycol) dimethacrylate. The device was tested with 28 rabbits, which were divided over two equal groups. In one group, the vasa deferentia were dissected and reanastomosed via microsurgical one-layer technique (end-to-end group). In the other group, the vasa deferentia were dissected and reattached through implantation of the mini-stent. Sperm counts revealed 100% patency in both groups, i.e. all vasovasostomies were successful. It was experienced that the operation was easier and faster in the case of the mini-stent, probably since the mini-stent keeps the lumens of both vas ends exactly in line during suturing. This study demonstrates the feasibility of the mini-stent. Further work is necessary to evaluate the utility of this approach for clinical vasovasostomies.

Vasectomy: a "seminal" analysis

Vasectomy is one of the most reliable and cost-effective permanent methods of contraception. Despite its popularity, certain issues pertaining to the procedure remain unresolved. Appropriate selection of candidates for vasectomy requires thorough counseling and screening, though a foolproof method of eliminating dissatisfaction and regret remains a mystery. Debate continues over the relative merits of the various techniques of isolating and sealing the vasal ends. Postoperative complication rates remain minimal regardless of the technique used, and no single strategy attempting to maximize patient compliance with postoperative semen analysis has enjoyed unmitigated success. Long-term consequences, other than regret, are rare. Finally, issues regarding residency training in the procedure and its impact on procedure morbidity are scarcely addressed in the literature. This study reviews the evolution of vasectomy as a contraceptive procedure and attempts to summarize current literature addressing these unresolved issues.

Vasectomy occlusion techniques for male sterilization

BACKGROUND

Vasectomy is an increasingly popular and effective family planning method. A variety of vasectomy techniques are used worldwide including various vas occlusion techniques (excision and ligation, thermal or electrocautery, and mechanical and chemical occlusion methods), vas irrigation and fascial interposition. Vasectomy guidelines largely rely on information from observational studies. Ideally, the choice of vasectomy techniques should be based on the best available evidence from randomized controlled trials.

OBJECTIVES

The objective of this review was to compare the effectiveness, safety, acceptability and costs of vasectomy techniques for male sterilization.

SEARCH STRATEGY

We searched the computerized databases the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Popline and LILACS. In addition, we searched the reference lists of relevant articles and book chapters.

SELECTION CRITERIA

We included randomized controlled trials and controlled clinical trials comparing vasectomy techniques.

DATA COLLECTION AND ANALYSIS

We assessed all titles and abstracts located in the literature searches and two reviewers independently extracted articles identified for inclusion. Data were presented in the text of the review. Outcome measures include contraceptive efficacy, safety, discontinuation, and acceptability.

MAIN RESULTS

Two trials compared vas occlusion with clips versus a conventional vasectomy technique; both were of poor quality. Neither trial found a difference between the two groups with regard to the primary outcome of failure to reach azoospermia. Four trials examined vas irrigation: three compared water irrigation with no irrigation and one compared water irrigation with euflavine. All of the trials were of poor quality. None of the trials found a significant difference between the groups with respect to the primary outcome of time to azoospermia. However, one trial found that the median number of ejaculations to azoospermia was significantly lower in the euflavine group compared to the water irrigation group. The one trial that compared vasectomy with fascial interposition versus vasectomy without fascial interposition was a high quality, large study that has only been partially reported at the time of this review. The fascial interposition group was significantly more likely to be related to vasectomy success (azoospermia) at 22 weeks. However, fascial interposition also was associated with significantly more surgical difficulties.

REVIEWERS' CONCLUSIONS

No conclusions can be made about the effectiveness, safety, acceptability and costs of vas occlusion technique or vas irrigation as studies that examined these were of low quality and underpowered. Fascial interposition is associated with improved vasectomy success but is associated with some increased surgical difficulty. Randomized controlled trials examining other vasectomy techniques were not available. More research is required to examine vasectomy techniques.

Development of methods of male contraception: impact of the World Health Organization Task Force

OBJECTIVE

To give an historical record of the research of the World Health Organization (WHO) Task Force to develop methods of male contraception; to examine the social, political, medical, pharmaceutical, funding, and other factors that influenced progress; and to suggest reasons why such methods are only now becoming available.

DESIGN

Review of basic and clinical research over 30 years.

SETTING

Task force of a multinational agency and collaborating agencies.

CONCLUSION(S)

Through the involvement of many international scientists, the WHO Task Force has uniquely contributed to the exploratory phases of the research in male contraception and by its multicenter contraceptive efficacy studies has accelerated progress towards the ideal hormonal method. Despite an adverse climate involving social and political attitudes, funding constraints, and pharmaceutical industry hesitation, WHO formed coalitions with governments and international agencies to sustain research with results that apply to men in culturally diverse populations and thereby to influence activities across the whole range of global reproductive health and family planning.

Prostate cancer update

Research has yielded important insights into the impact of radical prostatectomy in patients with localized prostate cancer. Other recent research has focused on the role of nutrition in prostate cancer development and progression, improved prognostication for patients with both early and advanced prostate cancer, efficacy of adjuvant and neoadjuvant hormonal therapy, and development of novel agents. In addition, the role of bisphosphonates in patients with bone metastasis was established.