The long-term influence of vasectomy on prostatic volume and morphology in man

A pioneer Turkish urologist-medical historian (Saim Erkun 1901-1949) and his one-century-old review about prostate

Saim Erkun (1901-1949) was born in Manisa at Aegean region of Anatolia as an Ottoman citizen. While his early life was spent in late Ottoman times at military actions including military prison camp in British colony; India, his active professional productive period was in early Turkish republic period (Est. 1923, centenary). He had a good education period for medicine with the help of his good level of all main World scientific languages such as French, German, and English. Besides his main profession, he was also interested in Ottoman urological medicine around the conquer of Istanbul and allocated them a space in his books in 1930s. He was one of the earliest urology resident (1929-1933, Istanbul) of modern medicine in Turkey. He performed many urological procedures and published the outcomes following modern scientific algorithms, furthermore, there have been urological books including "history" partly referring to antique Ottoman literature among his publications. In this manuscript we focused on the magic word of Urology forever; "Prostate," among his essays. Turkish medicine, particularly urology, renewed itself by some intelligent hard working young clinicians such as Saim Erkun, immediately after the short struggling by means of establishment process of modern Turkiye after World War I by the collapsing of old Ottoman Empire. Furthermore, we think that the stunning special word of urology, "prostate," should especially be mentioned to emphasize the importance of this beginning.

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 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.

Risk factors for surgically treated benign prostatic hyperplasia in Western Australia

OBJECTIVE

To determine the relationship between personal, hormonal and lifestyle risk factors and surgically treated benign prostatic hyperplasia (BPH).

MATERIALS AND METHODS

A population-based case-control study was conducted in Western Australia (WA) on men aged 40-75 years who were surgically treated at public and private hospitals for BPH during 2001-2002. Controls were recruited from the WA electoral roll. Cases and controls were compared with regard to demographic and lifestyle factors and proxy measures of hormonal status using logistic regression. Data were available for 398 cases and 471 controls.

RESULTS

No associations with BPH were found for family history of prostate cancer in father or brother, serving in the military in a combat area, pattern of baldness, smoking status, obesity, alcohol intake and occupational physical activity. The only inverse relationship was observed with heavy alcohol drinking (>30g/day), however, this was not statistically significant. An increased risk of BPH, not statistically significant, was observed for British-born men compared to Australian born and for history of vasectomy. The analysis was repeated after excluding 28% of controls with moderate and severe symptoms of BPH and 7% of cases with mild symptoms prior to surgery, and our results remained essentially unchanged.

CONCLUSIONS

The results suggest that there are few risk factors for BPH although perhaps country of birth, vasectomy and heavy alcohol consumption may be considered further.

Response of the adult prostate to prepubertal and postpubertal obstruction of the vas deferens in the rat

OBJECTIVES

To determine whether obstruction of the vas deferens alters several general measures of prostate development during puberty and during prostate maintenance in the adult rat. Previous reports have suggested the possibility that vasectomy results in alterations of prostate function in experimental animals and humans.

METHODS

Adult rats and 10-day-old rats were subjected to bilateral sham operations or bilateral vasectomy, and the prostates were extirpated either 14 or 60 days later. The total prostate weight and dorsolateral and ventral lobe total protein per milligram tissue, DNA per milligram tissue, and DNA per milligram protein were determined. Dorsolateral and ventral prostate lobe sections from each group were also stained with hematoxylin-eosin and subjected to histologic examination.

RESULTS

The histologic features of the adult rat prostate were not qualitatively altered by vasectomy whether it occurred before puberty or in adult animals with mature prostates. Furthermore, vasectomy did not significantly alter the prostate weight or the protein or DNA content of either the dorsolateral or ventral lobes of the prostate compared with the sham-operated animals of either age.

CONCLUSIONS

Vas deferens obstruction does not significantly alter the parameters associated with the development or maintenance of the adult rat prostate measured in this study.

The pathogenesis of benign prostatic hyperplasia: a proposed hypothesis and critical evaluation

PURPOSE

We used expanding observations regarding effects of testicular epididymal plasma and nonandrogenic testis factor(s) (NATF) on prostate growth to propose and evaluate a hypothesis regarding the development of benign prostatic hyperplasia (BPH) in man.

MATERIALS AND METHODS

Current experimental data regarding the presence of NATF were reviewed. The potential for their exposure to the prostate by various routes was assessed. These observations were coupled with recognized anatomical, histological and epidemiological characteristics of BPH to construct a hypothesis regarding its pathogenesis.

RESULTS

In vivo observations in man, rats and dogs supported the systemic secretion of NATF. These factors probably are, at least in part, spermatogenesis related. In vitro evaluation of the effect of spermatocele derived testicular epididymal plasma on human prostate stromal cells indicated the presence of androgen independent and androgen synergistic stromal growth promoters. These factors have potential local and systemic access to the prostate. The almost ubiquitous development of a regional, histologically variegated nodular growth occurring in the prostate in the androgen diminished environment of the aging man is compatible with local as well as systemic exposure to an age associated secretion of NATF.

CONCLUSIONS

We propose that human BPH is an induced phenomenon that is usually initiated by local episodic exposure of periurethral prostate to mitogens secreted by the testis/epididymis. Once initiated, isolated or complex interacting proliferative stimuli from the testis/epididymis and a variety of other sources may achieve exposure to the prostate by several routes and simulate prostate growth.

Is vasectomy a risk factor for prostate cancer?

Recently, several case-control studies have suggested that vasectomy may predispose to prostate cancer. Other studies have found no increase in risk. All of these studies have a number of limitations. Taken together, these studies do not provide convincing evidence that vasectomy increases the risk of prostate cancer. However, in view of the high prevalence of prostate cancer and the growing worldwide importance of vasectomy as a form of contraception, further epidemiological research is warranted. After briefly commenting on the experimental studies we will examine the epidemiological studies in more detail. This will be done by first summarising the designs and main findings of the most relevant published studies and then discussing methodological issues relating to the studies taken as a whole. Finally, we will present conclusions and offer recommendations for future research.

Does vasectomy have long-term effects on somatic and psychological health status?

All the major international articles on the somatic and psychological consequences of vasectomy published over the last 10 years have been reviewed and analysed. Although some experiments on animals have revealed harmful effects, none of the large-scale epidemiological studies has pointed to any increase in health risks (cardiovascular, hypertensive, psychiatric) in vasectomized men. The contradictions which arise between the clinical and large-scale epidemiological studies may be the result of methodological or experimental conditions. As our knowledge stands at present it can therefore be considered that vasectomy has no major effects on the physical or mental health of men.