The association between vasectomy and prostate cancer: a systematic review of the literature

Review of Vasectomy Complications and Safety Concerns

Vasectomy is a simple, safe, effective, and economical method used worldwide for long-term male contraception. As a surgical operation, it has short-term and long-term complications such as hematoma formation, infection, sterilization failure, sperm granulomas, short-term postoperative pain (nodal pain, scrotal pain, and ejaculation pain), and chronic pain syndrome. Whether it increases the risk of autoimmune disease, cardiovascular disease, testicular cancer, or prostate cancer is still controversial. Changes in plasma concentrations of luteinizing hormone, follicle-stimulating hormone, and testosterone after vasectomy have also been studied, as well as the relation between vasectomy and sexual function. Sperm quality decreases very slowly after vasectomy, and vasovasostomy and intracytoplasmic sperm injection could help a couple achieve a pregnancy if they change their minds at any point. We include a follow-up strategy and suggestions for follow-up care at the end of this review.

Systematic review and meta-analysis

In this review the usual methods applied in systematic reviews and meta-analyses are outlined. The ideal hypothesis for a systematic review should be generated by information not used later in meta-analyses. The selection of studies involves searching in web repertories, and more than one should be consulted. A manual search in the references of articles, editorials, reviews, etc. is mandatory. The selection of studies should be made by two investigators on an independent basis. Data collection on quality of the selected reports is needed, applying validated scales and including specific questions on the main biases which could have a negative impact upon the research question. Such collection also should be carried out by two researchers on an independent basis. The most common procedures for combining studies with binary outcomes are described (inverse of variance, Mantel-Haenszel, and Peto), illustrating how they can be done using Stata commands. Assessment of heterogeneity and publication bias is also illustrated with the same program.

The Effect of Vasectomy Reversal on Prostate Cancer Risk: International Meta-Analysis of 684,660 Vasectomized Men

PURPOSE

Evidence of the effect of vasectomy on prostate cancer is conflicting with the issue of detection bias a key criticism. We examined the effect of vasectomy reversal on prostate cancer risk in a cohort of vasectomized men. Evidence of a protective effect would be consistent with a harmful effect of vasectomy on prostate cancer risk while nullifying the issue of detection bias.

MATERIALS AND METHODS

Data were sourced from a total of 5 population level linked health databases in Australia, Canada and the United Kingdom. Cox proportional hazards regression analysis was used to compare the risk of prostate cancer in 9,754 men with vasectomy reversal to the risk in 684,660 with vasectomy but no reversal. Data from each jurisdiction were combined in a meta-analysis.

RESULTS

The combined analysis showed no protective effect of vasectomy reversal on the incidence of prostate cancer compared to that in men with vasectomy alone (HR 0.92, 95% CI 0.70-1.21).

CONCLUSIONS

These results align with those of previous studies showing no evidence of a link between vasectomy and prostate cancer.

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: 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 prostate cancer risk: a meta-analysis of cohort studies

Some studies have suggested that vasectomy is associated with the increased risk of prostate cancer, however, this conclusion is not supported by all the published studies. In order to examine the relationship between vasectomy and prostate cancer risk, we conducted a meta-analysis of cohort studies to clarify this controversial association. PubMed and Medline were used to identify the cohort studies that reported the association of vasectomy with prostate cancer risk from 1980 to January 2015. Based on a random effects model, the RR and 95% CI were used to assess the combined risk. In total, 10 cohort studies involving more than 7027 cases and 429914 participants were included. There was no significant relationship between vasectomy and prostate cancer risk, the pooled RR (95%CI) was 1.11[0.98, 1.27] (P = 0.109). In subgroup-analysis, the relationship between vasectomy and prostate cancer risk was not significantly modified by the length of follow-up and population distribution except Americans. Omission of any single study had little effect on the pooled risk estimate. Little evidence of publication bias was found. In conclusion, our meta-analysis suggests that vasectomy is not associated with the increased risk of prostate cancer. More studies based on other populations including the Chinese are needed.

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.

Systematic review of methods used in meta-analyses where a primary outcome is an adverse or unintended event

BACKGROUND

Adverse consequences of medical interventions are a source of concern, but clinical trials may lack power to detect elevated rates of such events, while observational studies have inherent limitations. Meta-analysis allows the combination of individual studies, which can increase power and provide stronger evidence relating to adverse events. However, meta-analysis of adverse events has associated methodological challenges. The aim of this study was to systematically identify and review the methodology used in meta-analyses where a primary outcome is an adverse or unintended event, following a therapeutic intervention.

METHODS

Using a collection of reviews identified previously, 166 references including a meta-analysis were selected for review. At least one of the primary outcomes in each review was an adverse or unintended event. The nature of the intervention, source of funding, number of individual meta-analyses performed, number of primary studies included in the review, and use of meta-analytic methods were all recorded. Specific areas of interest relating to the methods used included the choice of outcome metric, methods of dealing with sparse events, heterogeneity, publication bias and use of individual patient data.

RESULTS

The 166 included reviews were published between 1994 and 2006. Interventions included drugs and surgery among other interventions. Many of the references being reviewed included multiple meta-analyses with 44.6% (74/166) including more than ten. Randomised trials only were included in 42.2% of meta-analyses (70/166), observational studies only in 33.7% (56/166) and a mix of observational studies and trials in 15.7% (26/166). Sparse data, in the form of zero events in one or both arms where the outcome was a count of events, was found in 64 reviews of two-arm studies, of which 41 (64.1%) had zero events in both arms.

CONCLUSIONS

Meta-analyses of adverse events data are common and useful in terms of increasing the power to detect an association with an intervention, especially when the events are infrequent. However, with regard to existing meta-analyses, a wide variety of different methods have been employed, often with no evident rationale for using a particular approach. More specifically, the approach to dealing with zero events varies, and guidelines on this issue would be desirable.

Social origin of contraceptive counseling practices by male doctors in Mexico

Contraceptive counseling by physicians plays a decisive role in the contraceptive choices of their patients. We studied male physicians' contraceptive counseling and preferences in Mexico from a gender perspective. Specifically, through in-depth interviews with 31 male physicians working for public health institutions in Mexico, we examined reproductive health providers' contraceptive practices and perceptions about men's roles and responsibilities in reproduction. Through an interpretative analysis we identified the social processes involved in shaping contraceptive preferences. Of special importance are institutional and professional factors-related to prestige and economic concerns-framed by gender determinants which hinder the incorporation of practices that might contribute to gender equality in reproductive health. Thus, female contraceptive methods are preferred by physicians, and use of male contraceptive methods, especially vasectomy, is discouraged by them.

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.

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.

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.

Role of hormonal and other factors in human prostate cancer

American men have a lifetime risk of about 18% for prostate cancer diagnosis. Large international variations in prostate cancer risks and increased risks among migrants from low- to high-risk countries indicate important roles for environmental factors. Major known risk factors include age, family history, and country/ethnicity. Type 2 diabetes appears to reduce risk, while high birth weight and adult height are linked to increased risk of aggressive prostate cancer. Limited evidence supports an association with a history of sexually transmitted infections. A previous meta-analysis of eight cohort studies indicated no associations with plasma androgen, estrogen, or sex hormone binding globulin (SHBG) levels. However, there were dose-response relationships with baseline plasma testosterone levels in two studies that adjusted for other serum hormones and obesity. Finasteride (a drug that blocks testosterone activation) reduced prostate cancer risk by 25%. Low-frequency genes linked to familial prostate cancer only explain a small fraction of all cases. Sporadic cases were linked to relatively common polymorphisms of genes involved in (1) androgen synthesis, activation, inactivation and excretion, (2) hormone and vitamin D receptors, (3) carcinogen metabolism, and (4) DNA repair. Epidemiologic evidence supports protective roles for dietary selenium, vitamin E, pulses, tomatoes/lycopene, and soy foods, and high plasma 1,25-dihydroxyvitamin D levels. There is inadequate evidence that vegetables, fruit, carotenoids, and vitamins A and C reduce risk and that animal fat, alpha-linoleic acid, meat, coffee, and tea increase risk. Two major cohort studies found dose-response relationships with dietary calcium intake. Total dietary energy intake may enhance risk. Limited evidence supports a protective role for physical activity and elevated risk for farmers and other men with occupational pesticide exposure, particularly to organochlorine compounds and phenoxy herbicides. There is inadequate evidence for a relationship with alcohol or smoking. Most known or suspected external risk factors may act through hormonal mechanisms, but our review found little supporting evidence, and substantial further research is needed.

Vasectomie et chirurgies contraceptives déférentielles : aspects légaux et techniques

OBJECTIVES

To analyse technical innovations, their results and the changing legislation in France concerning sterilizing or contraceptive vas deferens surgery.

MATERIAL AND METHODS

A review of the literature was performed using the key words: male/contraception/vas deferens. From the 332 research articles obtained from PUBMED, we selected 54 articles for their methodological quality and the importance of their results.

RESULTS

Vasectomy remains the only validated vas deferens surgical technique. Although microsurgical reconstructive techniques have improved the vas deferens restoration rate, vasectomy must be considered to be a definitive method of sterilization. The other contraceptive (reversible) vas deferens surgical techniques have not demonstrated sufficient efficacy to be used outside of the context of clinical trials. However the encouraging results ofsome ofthese studies could allow their development in the intermediate term. From a legal point of view, since the reform of sterilizing surgery in Article L2123-1 of the French Public Health Act, vasectomy is now authorized in a regulatory framework.

CONCLUSION

The urology community must take into account progress in the field of contraceptive vas deferens surgical techniques.

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.

[Male and female sterilization techniques: Summary of ANAES assessments (May 2005)]

OBJECTIVE

To summarize assessments carried out by ANAES on male and female sterilization techniques. The summary was requested by the French Health Directorate after the law authorizing sterilization as a means of contraception was passed.

RESULTS (FEMALE STERILIZATION)

(i) EFFICACY of tubal ligation, electrocoagulation, clips or rings: the annual pregnancy rate is 0-2% depending on the study, with no significant difference between techniques. No data were found on fimbriectomy. (ii) EFFICACY of a hysteroscopically placed micro-insert device: no pregnancies were observed in patients with bilateral tube obstruction diagnosed by hysterosalpingography at 3 or at 6 months after placement (placement rate: 87-89%). (iii) SAFETY of tubal ligation, electrocoagulation, clips or rings: (a) By approach: There was no difference in the incidence of major complications between laparoscopy and minilaparotomy but there were significantly fewer minor complications with laparoscopy than with minilaparotomy. There were significantly more major complications with culdoscopy than with minilaparotomy and significantly more minor complications than with laparoscopy. (b) By operative technique: major and minor complications were significantly more common with the Pomeroy technique than with electrocoagulation; the difference could be due to the approach used. No data were available on fimbriectomy. (iv) SAFETY of a hysteroscopically placed micro-insert device: there were 11 cases of myometrial or tubal perforation among 734 patients (with device displacement into the peritoneal cavity in 3 cases).

RESULTS (MALE STERILIZATION)

(i)

EFFICACY

efficacy varied from 84% to 100% depending on the approach and the mode of vas deferens obstruction. There was no significant difference in efficacy according to approach (transcutaneous or scrotal). However, no conclusion could be drawn on the comparative efficacy of the occlusion techniques used from published data. (ii)

SAFETY

the rate of postoperative complications was low, below 10% in most series. Complications were benign and only rarely necessitated surgical revision.

CONCLUSION

The advantage of sterilization methods is that they lack any permanent contraindication. They should be presented as being generally irreversible. Fimbriectomy is not recommended for female sterilization. Laparoscopy is the preferred approach. Sterilization by hysteroscopic placement of a micro-insert device should be restricted to cases presenting a risk on laparoscopy; the technique should be re-assessed in 2006. The two approaches used for male sterilization are technically similar and do not seem to differ in efficacy. The Public Health Code states that "Fallopian tube or deferens duct ligation for contraceptive purposes is not allowed in minors" and that ligation "cannot be performed unless the adult involved has given his/her informed and motivated consent, expressed after taking into consideration clear, complete information on the consequences of the procedure". A waiting period of four months must follow the moment the decision to sterilize is taken and consent is given. An informed consent form must be signed. Sterilization in young or nulliparous women should be proposed with the greatest prudence and with many reservations.

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.

Reduced risk of prostate cancer in men who are childless as compared to those who have fathered a child: a population based case-control study

Androgens are believed to play a major role in the etiology of prostate cancer, but studies of sex-hormone exposure in relation to risk for prostate cancer have been inconclusive. Male fertility may be an indicator of long-term androgen status. To study the role of testicular function in prostate cancer development, we have assessed number of biological children in relation to risk for this malignancy. We carried out a population-based case-control study with retrospective ascertainment of cases occurring in Sweden between 1958-98. In total, 48,850 cases of prostate cancer were identified through the nation-wide Cancer Registry. For each case, one control, matched by year of birth, was randomly selected from the Swedish population. Information on offspring was obtained from the Swedish Multi-Generation Registry. We estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between number of offspring and risk for subsequent prostate cancer. Being childless or having fathered one child only were associated with reduced risks for prostate cancer compared to having fathered 2 or more children (OR = 0.83; 95% CI = 0.81-0.86 and OR = 0.93; 95% CI = 0.90-0.96, respectively). There was no further change in risk associated with fathering of more than 2 children. The risk for prostate cancer is reduced among childless men. A dysfunctioning reproductive apparatus fueling to a lesser extent prostatic growth, could be a plausible mechanism of this association.

Screening and treatment for prostate cancer: The evidence and implications for practice

Prostate cancer is the second most diagnosed cancer in men, but there is considerable debate over whether or not to screen for the condition. The issues in the debate surrounding screening are clarified in this paper. One of the recommendations of the guidelines for urology from the National Institute for Clinical Excellence (NICE, 2002) is that patients receive balanced information about management options for their condition.

The NICE guidelines also suggest that ‘major improvements' are required in information and support services for patients and carers, and that nurse specialists in the urology cancer team will play a key role in these services. The options for management and treatment are discussed in the light of these recommendations and the relative merits of each are considered.

[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.

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.

Vasectomy and the risk of prostate cancer: a meta-analysis examining vasectomy status, age at vasectomy, and time since vasectomy

The aim of this study was to conduct a quantitative review of prostate cancer studies to pool relative risk (RR) estimates on the association between prostate cancer and vasectomy, in an attempt to determine whether there is an association, and if so, its magnitude. Random-effects models were examined along with a linear model for time since vasectomy. The pooled RR estimate was 1.37 (95% CI=1.15-1.62) based on five cohort studies and 17 case-control studies. The RR estimate varied by study design with the lowest risk for population-based case-control studies. No difference was seen in risk by age at vasectomy. A linear trend based on the 16 studies reporting time since vasectomy suggested an 10% increase for each additional 10 y or a RR of 1.32 (95% CI=1.17-1.50) for 30 y since vasectomy. When null effects were assumed for the six studies not reporting information, the linear RR for the 22 studies was 1.07 (1.03-1.11) and 1.23 (1.11-1.37) for 10 and 30 y since vasectomy, respectively. These results suggest that men with a prior vasectomy may be at an increased risk of prostate cancer, however, the increase may not be causal since potential bias cannot be discounted. The overall association was small and therefore could be explained by bias. The latency effect shown here for time since vasectomy should be examined further.

Vasectomy and prostate cancer characteristics of patients referred for prostate biopsy

PURPOSE

The prospect of an association between vasectomy and prostate cancer has gained widespread attention and has potentially influenced patterns of referral. In patients referred for prostate needle biopsies we compared the incidence and characteristics of prostate cancer in those reporting a history of vasectomy to those denying prior vasectomy.

MATERIALS AND METHODS

A total of 585 consecutive prostate biopsy procedures were performed on 522 veterans during a 42-month period. Upon questioning 101 patients (19.3%) reported prior vasectomy. From the remaining 421 patients 202 consecutive age matched controls were selected. Pre-procedure prostate specific antigen levels, digital examination findings, incidence of prostate cancer, cancer grade and tumor length on biopsy cores were compared between the patients with and without a history of vasectomy.

RESULTS

Of the 101 patients who reported a history of vasectomy 46 (45.5%) had prostate cancer compared to 98 (48.5%) of the 202 age matched controls, and this difference was not statistically significant. Of the patients with prostate cancer those with prior vasectomy less frequently had an abnormal digital examination and lower prostate specific antigen levels, lower Gleason grade, lower clinical stage and shorter length of cancer on biopsies.

CONCLUSIONS

We found no increase in prostate cancer incidence or severity in patients referred for prostate biopsy who had undergone prior vasectomy. In fact, prostate cancer was less common with fewer poor prognostic indicators in patients with previous vasectomy. These findings may be secondary to either selection bias, as patients with a vasectomy may seek more routine medical care, or a greater tendency of primary providers to refer these patients for evaluation.

[Disagreement among hospital and community studies evaluating the same research question]

The goal of this review is to delineate some of reasons that justify the lack of consistency between hospital-based and community research. The main reasons for the differences are the selection of the hospital population and information based on clinical chart (its lack of uniformity and the treatment of the not available data). The reasons for lack of consistency are divided according to the type of research question: frequency, diagnosis, etiology, prognosis and treatment-prevention. The way a hospital population is selected justifies discrepancies regarding frequency and prognosis. As regards diagnosis, differences are mainly due the prevalence of disease. In the ascertainment of causality several biases are more common in hospital-based research, such as detection bias, protopathic (both producing an away-from-null estimate), and inclusion bias (diminishing the strength of association). Examples taken from the medical literature are offered to illustrate each bias. Regarding treatment-prevention problems arise from external validity, as clinical trials are less prone to bias; this latter situation is exemplified with an assessment of vaccine efficacy in both patients and healthy population. The frequency of citation of bias was assessed by a Medline search; in hospital studies detection bias and confounding by indication were more often quoted than in non-hospital research (RR = 2.71; 95% CI; 1.69-4.37; RR = 1.76; 95% CI, 0,90-3,42, respectively). Lastly, several recommendations are given to increase the validity of hospital-based research.

Vasectomy and prostate cancer in Québec, Canada

The present investigation measured the association between vasectomy and prostate cancer (PC) in the male population of Québec, Canada. The Québec Health Insurance Board and the Québec Cancer Registry were our principal sources of information. Lung cancer cases and the male population of Québec served as controls for comparative purposes. Within a retrospective design, our preliminary results indicate an association between vasectomy and PC. Among the 1925-39 birth cohort of individuals diagnosed with PC in 1990--93, the global odds ratio was 2.6 (95% CI=1.7--4.3) while it was compared with lung cancer as the control group. This risk increased with the length of time between vasectomy and the diagnosis of cancer. An historical design indicated strong cohesion of the results. Besides, the risk does not vary when we control for the place of residence of the individuals. Vasectomy seems to increase the risk of PC at least 10 years after the operation, but we cannot exclude the impact of a possible detection bias among vasectomized individuals.

Vasectomy

Vasectomy is regarded as the safest method now available for male fertility control. Almost 100 million men worldwide have relied on vasectomy for family planning. This review discusses all currently relevant operative techniques, including no-scalpel vasectomy, complications, possible long-term effects on the testis and epididymis, and diseases for which associations with vasectomy have been suggested, such as arteriosclerosis, autoimmune diseases and cancer of the prostate and testis. Other topics of discussion include the timing of post-operative semen analysis, patient noncompliance concerning post-operative controls, persistent cryptozoospermia and transient reappearance of spermatozoa after vasectomy, vasectomy failure and legal aspects.

Population-based outcomes after 28,246 in-hospital vasectomies and 1,902 vasovasostomies in Western Australia

OBJECTIVES

To examine trends in vasectomy and vasovasostomy, and the surgical complications and factors associated with reversal after vasectomy, and paternity after vasovasostomy.

PATIENTS AND METHODS

Procedure rates were estimated from 1980 to 1996 in the population of Western Australia. Linked hospital morbidity records were used in the follow-up of men after vasectomy to estimate the risks of complications and reversals. Records of vasovasostomies were linked to the paternity field on birth registrations. Independent effects of the study factors were examined using Cox regression.

RESULTS

There was little net change in vasectomy rates, whereas vasovasostomy rates increased in men aged 30-49 years. Risks of surgical complications were low and decreased for vasovasostomy. At 12-15 years after vasectomy, the risk of reversal levelled at 2. 4% in the total cohort and at 11.1% in men aged 20-24 years. The risk of vasovasostomy was 69% greater after vasectomy performed in 1994-96 than in 1980-84 (P = 0.011). The factors strongly associated with reversal were age < 30 years and being single, divorced or separated at the time of vasectomy. Paternity was achieved after an estimated 53% of vasovasostomies. Successful reversal was more likely if the man was younger at vasectomy and the time elapsed was comparatively short. Compared with vasovasostomies performed in 1980-84, the success rate of those in 1994-96 was almost four times higher.

CONCLUSION

Population rates of vasectomy are stable but the risk of seeking a reversal has increased. Outcomes after vasovasostomy have improved. Care should be taken during the counselling of men before vasectomy, and especially in those aged <30 years.

Safety and effectiveness of vasectomy

OBJECTIVE

To recommend further research on vasectomy based on a systematic review of the effectiveness and safety of vasectomy.

DESIGN

A systematic MEDLINE review of the literature on the safety and effectiveness of vasectomy between 1964 and 1998.

MAIN OUTCOME MEASURE(S)

Early failure rates are <1%; however, effectiveness and complications vary with experience of surgeons and surgical technique. Early complications, including hematoma, infection, sperm granulomas, epididymitis-orchitis, and congestive epididymitis, occur in 1%-6% of men undergoing vasectomy. Incidence of epididymal pain is poorly documented. Animal and human data indicate that vasectomy does not increase atherosclerosis and that increases in circulating immune complexes after vasectomy are transient in men with vasectomies. The weight of the evidence regarding prostate and testicular cancer suggests that men with vasectomy are not at increased risk of these cancers.

CONCLUSION(S)

Publications to date continue to support the conclusion that vasectomy is a highly effective form of contraception. Future studies should include evaluations of the long-term effectiveness of vasectomy, evaluating criteria for postvasectomy discontinuation of alternative contraception for use in settings where semen analysis is not practical, and characterizing complications including chronic epididymal pain syndrome.