Risk of testicular cancer after vasectomy: cohort study of over 73,000 men

The review of the long-term health risks associated with vasectomy

Vasectomy, a permanent method of preventing the release of sperm, has been widely used as effective birth control, with millions of men undergoing the procedure worldwide each year. Although vasectomy is effective and relatively simple, it is still a subject that receives considerable scrutiny, especially regarding any health effects. Indeed, the relationship between vasectomy and health risks has been a controversial topic. This review includes the examination of the evidence linking vasectomy to oncologic sequelae (i.e. prostate and testicular cancer). In addition, a review of the literature linking vasectomy to sexual dysfunction, cardiovascular disease, primary progressive aphasia/frontotemporal dementia, anti-sperm antibodies, and reproductive hormone changes is also presented. Overall, vasectomy appears safe with no convincing evidence for long term health risks.

[Recommendations of the Committee of Andrology and Sexual Medicine of the AFU concerning the management of Vasectomy]

OBJECTIVES

To answer the main clinical questions asked by practitioners and men consulting for a vasectomy request.

METHOD

The CPR method was used. The clinical questions were formulated according to the PICO methodology. A Pubmed literature search for the period 1984-2021 identified 508 references, of which 79 were selected and analyzed with the GRADE grid.

RECOMMENDATIONS

Vasectomy is a permanent, potentially reversible contraception. It is a safe procedure. A second vasectomy is necessary in only 1 % of cases. Surgical complications (hematoma, infection, pain, etc.) are rare. The frequency of prolonged scrotal pain after vasectomy is about 5 %, and less than 2 % describe a negative impact of this pain on their quality of life. Vasectomy does not have negative consequences on sexuality. The only contraindication to vasectomy is the minor patient. Patients at increased risk of remorse are single, divorced or separated men under the age of 30. Sperm storage may be particularly appropriate for them. Whatever the reason, the law allows the surgeon to refuse to perform the vasectomy. He must inform the patient of this at the first consultation. The choice of the type of anesthesia is left to the discretion of the surgeon and the patient. It must be decided during the preoperative consultation. Local anesthesia should be considered first. General anesthesia should be particularly considered in cases of anxiety or intense sensitivity of the patient to palpation of the vas deferens, difficulty palpating the vas deferens, or a history of scrotal surgery that would make the procedure more complex. Concerning the vasectomy technique, 2 points seem to improve the efficiency of the vasectomy: coagulation of the deferential mucosa and interposition of fascia. Leaving the proximal end of the vas deferens free seems to reduce the risk of post-vasectomy syndrome without increasing the risk of failure or complications. No-scalpel vasectomy is associated with a lower risk of postoperative complications than conventional vasectomy. Regarding follow-up, it is recommended to perform a spermogram at 3 months post-vasectomy and after 30 ejaculations. If there are still a few non-motile spermatozoa at 3 months, it is recommended that a check-up be performed at 6 months post-vasectomy. In case of motile spermatozoa or more than 100,000 immobile spermatozoa/mL at 6 months (defining failure), a new vasectomy should be considered. Contraception must be maintained until the effectiveness of the vasectomy is confirmed.

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: AUA guideline

PURPOSE

The purpose of this guideline is to provide guidance to clinicians who offer vasectomy services.

MATERIALS AND METHODS

A systematic review of the literature using the search dates January 1949-August 2011 was conducted to identify peer-reviewed publications relevant to vasectomy. The search identified almost 2,000 titles and abstracts. Application of inclusion/exclusion criteria yielded an evidence base of 275 articles. Evidence-based practices for vasectomy were defined when evidence was available. When evidence was insufficient or absent, expert opinion-based practices were defined by Panel consensus. The Panel sought to define the minimum and necessary concepts for pre-vasectomy counseling; optimum methods for anesthesia, vas isolation, vas occlusion and post-vasectomy follow up; and rates of complications of vasectomy. This guideline was peer reviewed by 55 independent experts during the guideline development process.

RESULTS

Vas isolation should be performed using a minimally-invasive vasectomy technique such as the no-scalpel vasectomy technique. Vas occlusion should be performed by any one of four techniques that are associated with occlusive failure rates consistently below 1%. These are mucosal cautery of both ends of the divided vas without ligation or clips (1) with or (2) without fascial interposition; (3) open testicular end of the divided vas with MC of abdominal end with FI and without ligation or clips; and (4) non-divisional extended electrocautery. Patients may stop using other methods of contraception when one uncentrifuged fresh semen specimen shows azoospermia or ≤ 100,000 non-motile sperm/mL.

CONCLUSIONS

Vasectomy should be considered for permanent contraception much more frequently than is the current practice in the U.S. and many other nations. The full text of this guideline is available to the public at http://www.auanet.org/content/media/vasectomy.pdf.

Register-based research: some methodological considerations

AIMS

Collecting new research data is often time consuming and expensive and it may be difficult to recruit volunteers to provide data for research. We should therefore make sure that we do not collect data that already are available and in the Nordic countries we have an opportunity to use national registers for certain types of research. In some situations using these population-based registers is preferable to collecting primary data since selection bias due to nonresponders is not a problem in these registers.

METHODS

Register-based data can be used in most designs available in observational studies and even add important data to randomised trials. Getting access to using the valuable data sources stored in national registers is much easier now that it was in the past. However, we still need better documentation and we should to a much larger extent be able to use research files that combine data from two or more of the Nordic countries. Linking primary research data to public registers will also provide new research opportunities.

RESULTS

Nordic registers have been used in several landmark papers over the years.

CONCLUSIONS

Register-based research can be done without risk of unwanted disclosure of personal data and it involves no invasive procedures. It is a valuable gift given by the people to be used for the people.

Epidemiology of testicular cancer

Testicular cancer is of interest and importance because its incidence has been increasing in most countries over the past four decades. Although it remains an uncommon malignancy overall accounting for 1-2% of all tumours in men, testicular cancer is the most common malignancy in young men. There is marked geographical variation in the incidence of testicular cancer, with the highest incidence among men in Nordic countries and lowest incidence among men in the Middle East and Asia. The association between some risk factors, including cryptorchidism, a previous history of testicular cancer and a family history of testicular cancer, and the incidence of testicular cancer has been widely reported. We reviewed published reports and present the evidence to support or refute the association between the well-established and the less well-established risk factors and the incidence of testicular cancer.

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.

Sterilization in the United States

Unintended pregnancies are expensive for patients and for society in terms of medical costs, the cost of caring for more children, and the cost to personal and professional goals. Sterilization is the most common contraceptive method utilized by couples in the United States. Given technological advances over the past few decades, male and female surgical sterilization has become a safe, convenient, easy, and highly effective birth control method for the long term. This article reviews current male and female sterilization options.

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.

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.

Epidemiology of testicular cancer: An overview

Testicular cancer is a rare disease, accounting for 1.1% of all malignant neoplasms in Canadian males. Despite the low overall incidence of testicular cancer, it is the most common malignancy among young men. The incidence rate of testicular cancer has been increasing since the middle of the 20th century in many western countries. However, the etiology of testicular cancer is not well understood. A search of the peer-reviewed literature was conducted to identify important articles for review and inclusion in this overview of the epidemiology of testicular cancer. Most of the established risk factors are related to early life events, including cryptorchidism, carcinoma in situ and in utero exposure to estrogens. Occupational, lifestyle, socioeconomic and other risk factors have demonstrated mixed associations with testicular cancer. Although there are few established risk factors for testicular cancer, some appear to be related to hormonal balance at various life stages. Lifestyle and occupational exposures occurring later in life may play a role in promoting the disease, although they are not likely involved in cancer initiation. In addition to summarizing the current epidemiologic evidence on risk factors for testicular cancer, we suggest future research directions that may elucidate the etiology of testicular 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.

Canadian Contraception Consensus

This document has been archived because it contains outdated information. It should not be consulted for clinical use, but for historical research only. Please visit the journal website for the most recent guidelines.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

Dietary risk factors for testicular carcinoma

Although testicular cancer is a relatively rare lesion, accounting for only 1.1% of all malignant neoplasms in males in Canada, it is the most common cancer among Canadian men 20-45 years of age. Knowledge of the causes of testicular cancer risk in general, and more specifically, its association with diet, remain limited. Data from 601 cases of testicular cancer and 744 population-based controls collected in 8 of the 10 Canadian provinces between 1994-97 were used to explore the relationship between diet and testicular cancer risk. We systematically examined 17 food groups, 15 nutrients and 4 individual foods based on data collected through a 69-item food-frequency questionnaire. Our results suggest that high dairy product intake, in particular high intake of cheese (odds ratio [OR] = 1.87; 95% confidence interval [CI] 1.22-2.86; p-trend < 0.001), is associated with an elevated risk of testicular cancer in Canadian males.

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.

Use of large medical databases to study associations between diseases

We describe the use of a dataset of statistical medical records, the Oxford Record Linkage Study (ORLS), to identify diseases which occur together more commonly (association), or less commonly (dissociation), than their individual frequencies in the population would predict. We investigated some conditions known or suspected to enhance the subsequent risk of cancer, some conditions thought to be linked with schizophrenia, and some associations between conditions with a known autoimmune component. Diseases may occur in combination more often (or less often) than expected by chance because one predisposes to (or protects against) another or because they share environmental and/or genetic mechanisms in common. The investigation of such associations can yield important information for clinicians interested in potential disease sequelae, for epidemiologists trying to understand disease aetiology, and for geneticists attempting to determine the genetic basis of variation in disease course among individuals. We suggest that, through the use of datasets like the ORLS, it will be possible to 'map' comprehensively the phenomic expression of co-occurring diseases.

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.

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

OBJECTIVE

To evaluate the possible association between vasectomy and prostate cancer.

DESIGN

Systematic review of the literature.

PATIENT(S)

Fourteen original studies published between January 1985 and December 1996 that addressed the association between vasectomy and prostate cancer.

MAIN OUTCOME MEASURE(S)

The strength of the association was estimated with the use of a meta-analysis (DerSimonian and Laird method). A sensitivity analysis was conducted to assess the impact of different sources of heterogeneity.

RESULT(S)

Fourteen original papers were reviewed (5 cohort and 9 case-control studies). Relative risks ranged between 0.44 (95% confidence interval [CI] = 0.1-4.0) and 6.70 (95% CI = 2.1-21.6). The overall relative risk (DerSimonian and Laird estimate) was 1.23 (95% CI = 1.01-1.49). The sensitivity analysis showed that this measure was very sensitive to the study base, the type of design used, and the possibility of bias. Further, the funnel plot demonstrated the probable existence of publication bias.

CONCLUSION(S)

No causal association was found between vasectomy and prostate cancer. Individuals who have undergone vasectomy are not at high risk for the development of prostate cancer.

Environmental endocrine disruption: an effects assessment and analysis

This report is an overview of the current state of the science relative to environmental endocrine disruption in humans, laboratory testing, and wildlife species. Background information is presented on the field of endocrinology, the nature of hormones, and potential sites for endocrine disruption, with specific examples of chemicals affecting these sites. An attempt is made to present objectively the issue of endocrine disruption, consider working hypotheses, offer opposing viewpoints, analyze the available information, and provide a reasonable assessment of the problem. Emphasis is placed on disruption of central nervous system--pituitary integration of hormonal and sexual behavioral activity, female and male reproductive system development and function, and thyroid function. In addition, the potential role of environmental endocrine disruption in the induction of breast, testicular, and prostate cancers, as well as endometriosis, is evaluated. The interrelationship of the endocrine and immune system is documented. With respect to endocrine-related ecological effects, specific case examples from the peer-reviewed literature of marine invertebrates and representatives of the five classes of vertebrates are presented and discussed. The report identifies some data gaps in our understanding of the environmental endocrine disruption issue and recommends a few research needs. Finally, the report states the U.S. Environmental Protection Agency Science Policy Council's interim position on endocrine disruption and lists some of the ongoing activities to deal with this matter.

Is vasectomy harmful to health?

Since the late 1960s, vasectomy has been a popular and widely used form of contraceptive in Britain for couples who do not want to have any more children. However, throughout the past decade there has been considerable concern about the safety of this procedure. This paper reviews the current opinion on the possible health considerations associated with this operation and shows that the latest news is mostly reassuring.

A change in practice: current urologic practice in response to reports concerning vasectomy and prostate cancer

OBJECTIVE

To examine the practice patterns of urologists performing vasectomy in response to studies reporting an increased risk of prostate cancer in vasectomized men.

DESIGN

A mailed survey.

SETTING

A university medical institution.

PARTICIPANTS

One thousand five hundred randomly selected United States urologists under the age of 65 years.

MAIN OUTCOME MEASURE

Urologists reported practice patterns of vasectomy in response to studies showing possible link between vasectomy and prostate cancer.

RESULTS

A response rate of 51% (759/1,500) was obtained. Although > 90% state that these studies have had little or no effect upon their practice of vasectomy, 27% screen vasectomized men earlier for prostate cancer, and 20% would be reluctant to recommend a vasectomy to a man with a strong family history of prostate cancer.

CONCLUSIONS

Over one fourth of urologists who screen for prostate cancer have altered their screening patterns even though they responded that the studies have not affected their practice patterns.

Contraception for the older woman

Contraception presents particular problems for women over the age of 40. Although fertility is declining and the risk of pregnancy may be small, the consequences of an unplanned pregnancy may be socially devastating and medically ill-advised. Menstrual dysfunction and psychosexual difficulties increase with age and may exacerbate the side-effects of some methods of contraception. The long-term risks of combined hormonal contraception, particularly cardiovascular disease, become more pertinent to women whose natural risk of disease increases with age. Patterns of sexual activity and contraceptive use change with age. The advantages and disadvantages of currently available methods of contraception are difficult to quantify, and the choice of method is very much a matter for individual concern. The increasing prevalence of HRT may complicate matters for some women who are unsure for how long to continue using contraception. Contraceptives of the future may be designed to improve the reproductive health of all women, particularly those approaching the menopause.

Sterilization

Sterilization is accepted as a permanent method of contraception by many couples in the world. Female sterilization is more widely used than male sterilization, but the latter is used by many couples in developed countries. The most widely used methods for female sterilization are simple tubal ligation, electrocautery of the fallopian tubes, and occlusion of the tubes by Hulka or Filshie clips or Falope rings. These procedures may be carried out either by minilaparotomy or by laparoscopy, under local anaesthesia. Sterilization may be performed immediately following pregnancy, or as an interval operation. The effectiveness of female sterilization is high, with failure rates of about 1-2 per 1000 procedures. Immediate complications are few and minor, while there appear to be no serious, long-term adverse effects. It is possible that there is a protective effect against ovarian cancer. Potential new technologies for female sterilization include the use of chemicals, such as quinacrine, for transcervical tubal occlusion, and hysteroscopic methods. Male sterilization is more simple and can readily be performed under local anaesthesia. A new technique originating in China, the no-scalpel technique, has made the procedure even more simple and produces fewer complications such as haematoma. It is possible that the direct injection of plug-forming material into the vas may render the procedure more reversible. Concerns about possible adverse effects of vasectomy on cardiovascular diseases and testicular cancer largely have been dispelled, but a possible weak association between vasectomy and prostatic cancer continues to be studied.