Early and Late Long-Term Effects of Vasectomy on Serum Testosterone, Dihydrotestosterone, Luteinizing Hormone and Follicle-Stimulating Hormone Levels

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.

Impact of Vasectomy on the Development and Progression of Prostate Cancer: Preclinical Evidence

Some observational studies have implied a link between vasectomy and an elevated risk of prostate cancer. We investigated the impact of vasectomy on prostate cancer outgrowth, mainly using preclinical models. Neoplastic changes in the prostate were compared in transgenic TRAMP mice that underwent vasectomy vs. sham surgery performed at 4 weeks of age. One of the molecules identified by DNA microarray (i.e., ZKSCAN3) was then assessed in radical prostatectomy specimens and human prostate cancer lines. At 24 weeks, gross tumor (p = 0.089) and poorly differentiated adenocarcinoma (p = 0.036) occurred more often in vasectomized mice. Vasectomy significantly induced ZKSCAN3 expression in prostate tissues from C57BL/6 mice and prostate cancers from TRAMP mice. Immunohistochemistry showed increased ZKSCAN3 expression in adenocarcinoma vs. prostatic intraepithelial neoplasia (PIN), PIN vs. non-neoplastic prostate, Grade Group ≥3 vs. ≤2 tumors, pT3 vs. pT2 tumors, pN1 vs. pN0 tumors, and prostate cancer from patients with a history of vasectomy. Additionally, strong (2+/3+) ZKSCAN3 expression (p = 0.002), as an independent prognosticator, or vasectomy (p = 0.072) was associated with the risk of tumor recurrence. In prostate cancer lines, ZKSCAN3 silencing resulted in significant decreases in cell proliferation/migration/invasion. These findings suggest that there might be an association between vasectomy and the development and progression of prostate cancer, with up-regulation of ZKSCAN3 expression as a potential underlying mechanism.

Vasectomy and Prostate Cancer Risk: A 38-Year Nationwide Cohort Study

BACKGROUND

A man's risk of prostate cancer has been linked to his prior reproductive history, with low sperm quality, low ejaculation frequency, and a low number of offspring being associated with increased prostate cancer risk. It is, however, highly controversial whether vasectomy, a common sterilization procedure for men, influences prostate cancer risk.

METHODS

We established a cohort of all Danish men (born between 1937 and 1996) and linked information on vasectomy, doctor visits, socioeconomic factors, and cancer from nationwide registries using unique personal identification numbers. Incidence risk ratios for prostate cancer by time since vasectomy and age at vasectomy during the follow-up were estimated using log-linear Poisson regression.

RESULTS

Overall, 26 238 cases of prostate cancer occurred among 2 150 162 Danish men during 53.4 million person-years of follow-up. Overall, vasectomized men had an increased risk of prostate cancer compared with nonvasectomized men (relative risk = 1.15, 95% confidence interval = 1.10 to 1.20). The increased risk of prostate cancer following vasectomy persisted for at least 30 years after the procedure and was observed regardless of age at vasectomy and cancer stage at diagnosis. Adjustment for the number of visits to the doctor and socioeconomic factors did not explain the association.

CONCLUSIONS

Vasectomy is associated with a statistically significantly increased long-term risk of prostate cancer. The absolute increased risk following vasectomy is nevertheless small, but our finding supports a relationship between reproductive factors and prostate cancer risk.

RISUG® as a male contraceptive: journey from bench to bedside

Even after decades of research men still lack reliable and reversible contraceptive methods comparable to female methods of contraception. Traditional methods of male contraception present a high failure rate and also involve high risk both when used for contraception and for protection against sexually transmitted diseases. Various chemical, hormonal, immunological, vas based and herbal methods of contraception have been examined by scientists world over during the past four decades. Among the possible lead approaches, exogenous hormonal contraception, either alone or in combination with progesterone or antiandrogen, is being viewed at low profile because of their insufficiency in inducing uniform suppression of spermatogenesis and steroid related long term complications. As an alternative to vasectomy, among various intravasal devices being examined, RISUG® (Reversible Inhibition of Sperm Under Guidance), a co-polymer of styrene and maleic anhydride offers long term contraception with safety, efficacy and it can be delivered by no-scalpel injection. Thus it is the only male contraceptive procedure currently under Phase- III Clinical Trial. The non-invasive reversal technique, successfully demonstrated in langur monkeys and functional reversal achieved with dimethyl sulphoxide (DMSO) and sodium bicarbonate (NaHCO3) in rats and rabbits with safety at F1 generation (first filial generation) have projected RISUG® as a better alternative to vasectomy. In this narrative review we revisit the long journey of RISUG® beginning with formulation on a bench towards reaching the market as a safe and effective contraceptive method, discussing various milestones and roadblocks of this expedition awaiting the mandatory regulatory clearance from the Government of India. Successful completion of ongoing phase III clinical trials with demonstration of reversal in human volunteers will give an indigenously developed male contraceptive to the world.

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.

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.

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 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.

Association between plasma 25-OH vitamin D and testosterone levels in men

OBJECTIVE

A small randomized controlled trial suggested that vitamin D might increase the production of testosterone in men, which is supported by experimental studies in animals and a cross-sectional study showing positive associations between plasma 25-hydroxyvitamin D [25(OH)D] and testosterone and concordant seasonal variation of both biomarkers.

DESIGN AND MEASUREMENTS

We investigated the cross-sectional association of plasma 25(OH)D levels and total and free testosterone measured by immunoassay in 1362 male participants of the Health Professionals Follow-up Study who were selected for a nested case-control study on prostate cancer using multivariate-adjusted linear and restricted cubic spline regression models.

RESULTS

25(OH)D was positively associated with total and free testosterone levels. From the lowest to the highest 25(OH)D quintile, multivariate-adjusted means (95% confidence interval) were 18·5 (17·7; 19·4), 19·4 (18·6; 20·2), 19·6 (18·8; 20·4), 20·1 (19·3; 20·9) and 20·0 (19·1; 20·8; P-trend = 0·003) for total testosterone and 97·7 (93·9; 101·5), 98·2 (94·1; 102·2), 99·2 (95·2; 103·2), 100·7 (96·9; 104·5) and 101·5 (97·6; 105·4; P-trend = 0·03) for free testosterone. The shapes of the dose-response curves indicate that the association between 25(OH)D and total and free testosterone is linear at lower levels of 25(OH)D (below approximately 75-85 nmol/l), reaching a plateau at higher levels. Unlike for 25(OH)D, we did not observe any seasonal variation of testosterone concentrations.

CONCLUSION

This study supports previously reported positive associations between vitamin D and testosterone although we did not observe parallel seasonal variation patterns. Possible causality and direction of the vitamin D-testosterone association deserve further scientific investigation.

Survivin downregulation is associated with vasectomy-induced spermatogenic damage and apoptosis

OBJECTIVE

To evaluate the expression of the apoptotic genes survivin, Bax and Bcl-2 in vasectomized rabbits and to determine their relation with vasectomy-induced spermatogenic impairment and germ cell apoptosis.

MATERIALS AND METHODS

Twelve adult rabbits (6-12 months old) were divided into three groups: sham control, unilateral vasectomy or bilateral vasectomy. Six months after vasectomy, testicular tissue was analyzed for germ cell apoptosis and DNA fragmentation by the TUNEL assay and gel electrophoresis, respectively. Spermatogenesis was assessed using the Johnsen score. The relative gene expression of survivin, Bax and Bcl-2 was measured using reverse transcription followed by real-time PCR.

RESULTS

Compared to sham animals, a significant decrease in testicular survivin mRNA levels was measured in the two vasectomy animal groups (p < 0.05). This was accompanied by a significant increase in the Bax:Bcl-2 ratio in the vasectomized animals (p < 0.05). In addition, these data showed positive correlation with enhanced apoptotic index, damage to spermatogenesis and DNA fragmentation after vasectomy.

CONCLUSION

These findings demonstrate that vasectomy-induced damage to spermatogenesis due to testicular apoptosis may be associated with survivin downregulation and Bax overexpression.

Effects of vasectomy on spermatogenesis and fertility outcome after testicular sperm extraction combined with ICSI

BACKGROUND

Each year 40,000 men have a vasectomy in the UK whilst another 2400 request a reversal to begin a second family. Sperm can now be obtained by testicular biopsy and subsequently used in assisted conception with ICSI. The study aims were to compare sperm yields of men post-vasectomy or with obstructive azoospermia (OA) of unknown aetiology with yields of fertile men and to assess any alteration in the clinical pregnancy rates after ICSI.

METHODS

Testicular tissue was obtained by Trucut needle from men who had undergone a vasectomy >5 years previously or had OA from other causes and from fertile men during vasectomy. Seminiferous tubules were milked to measure sperm yields. Numbers of Sertoli cells and spermatids and thickness of the seminiferous tubule walls were assessed using quantitative computerized analysis.

RESULTS AND CONCLUSIONS

Sperm yields/g testis were significantly decreased in men post-vasectomy and in men with OA, relative to fertile men. Significant reductions were also observed in early (40%) and mature (29%) spermatid numbers and an increase of 31% was seen in the seminiferous tubule wall (basal membrane and collagen thickness) of vasectomized men compared with fertile men. Clinical pregnancy rates in couples who had had a vasectomy were also significantly reduced.

[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 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.

Analysis of the relationship between histologic alterations and the generation of reactive oxygen species in vasectomized rat testes

OBJECTIVES

To evaluate the effects of vasal obstruction on testicular structure, to determine if tissue and/or cell damage can cause significant reactive oxygen species (ROS) generation, and to correlate the histologic alterations to the measured levels of ROS products.

METHODS

To evaluate the effects of ROS generation in vasectomized testes, unilateral vasectomy was performed on 17 rats and tissue samples were examined by light microscopy. The histologic alterations were correlated to the measured tissue malondialdehyde levels by thiobarbituric acid analysis as an indicator of the ROS-induced tissue damage.

RESULTS

Unilateral vasectomy significantly affected the weights of the ipsilateral testes, but not the contralateral testes. No significant changes were noted in plasma estradiol, follicle-stimulating hormone, luteinizing hormone, and testosterone levels. The mean values of malondialdehyde were found to be significantly higher in vasectomized rats than in control rats (0.025 +/- 0.008 versus 0.018 +/- 0.007 nmol/mg protein) (P < 0.01). The malondialdehyde level was a mean of 28% lower in the contralateral testes tissue as compared to that found in ipsilateral testes (P < 0.01). Malondialdehyde output from vasectomized rats had a parallel correlation to tissue destruction.

CONCLUSIONS

Our results indicate that overproduction of ROS may be involved in vasectomy-induced testicular damage.

Vasectomy is associated with an increased risk for urolithiasis

We evaluated vasectomy as a potential risk factor for urolithiasis. Vasectomy is a common method of contraception among otherwise healthy men. This is also the population at highest risk for urolithiasis. We conducted a case-control study of patients in a large prepaid health maintenance organization. Cases were men experiencing initial episodes of urolithiasis, ascertained by reviewing radiology logs and medical records. The age-matched controls were men with no history of urolithiasis. In logistic regression models, the relative risk of urolithiasis for men with vasectomies compared with men without vasectomies was 1.9 for men younger than 46 years of age (95% confidence interval = 1.2 to 3.1, P = 0.005), and the relative risk was 0.9 (95% confidence interval = 0.5 to 1.5, P > 0.8) for men who were at least 46 years old. The relative risk of urinary calculi was 2.0 (95% confidence interval 1.0 to 4.1, P < 0.05) for men with vasectomies 0 to 4 years before evaluation compared with men without vasectomies, and the excess risk persisted as long as 14 years postvasectomy. Vasectomy was associated with a twofold increased risk for urolithiasis in men younger than 46 years of age. This increased risk may persist for up to 14 years postvasectomy. Given the large number of men who undergo vasectomy worldwide each year, the increased risk for urolithiasis among vasectomized men may result in substantial excess morbidity.