Andrological aspects of testicular cancer

A Brief Review of the Link between Environment and Male Reproductive Health: Lessons from Studies of Testicular Germ Cell Cancer

During the past few decades there has been a significantly increasing trend in germ cell tumours all over the world, particularly in countries with Caucasian populations. The changes in incidence have occurred so fast that only environmental factors can explain this development. This review focuses on the hypothesis that testicular germ cell cancer, which originates from germ cell neoplasia in situ, is of foetal origin and associated with other male reproductive problems through a testicular dysgenesis syndrome, also including foetal origin of impaired spermatogenesis, hypospadias and cryptorchidism. There is little doubt that environmental factors associated with modern lifestyles have - in a broad sense - had an adverse influence on male reproductive health. The hypothesis that exposure to endocrine-disrupting chemicals plays a fundamental role in this trend is plausible. This is based on evidence from animal studies that demonstrate adverse reproductive effects caused by a number of endocrine-disrupting chemicals to which humans are exposed as part of our modern lifestyle.

Possible fetal determinants of male infertility

Although common reproductive problems, such as male infertility and testicular cancer, present in adult life, strong evidence exists that these reproductive disorders might have a fetal origin. The evidence is derived not only from large epidemiological studies that show birth-cohort effects with regard to testicular cancer, levels of testosterone and semen quality, but also from histopathological observations. Many infertile men have histological signs of testicular dysgenesis, including Sertoli-cell-only tubules, immature undifferentiated Sertoli cells, microliths and Leydig cell nodules. The most severe gonadal symptoms occur in patients with disorders of sexual development (DSDs) who have genetic mutations, in whom even sex reversal of individuals with a 46,XY DSD can occur. However, patients with severe DSDs might represent only a small proportion of DSD cases, with milder forms of testicular dysgenesis potentially induced by exposure to environmental and lifestyle factors. Interestingly, maternal smoking during pregnancy has a stronger effect on spermatogenesis than a man's own smoking. Other lifestyle factors such as alcohol consumption and obesity might also have a role. However, increasing indirect evidence exists that exposure to ubiquitous endocrine disrupting chemicals, present at measurable concentrations in individuals, might affect development of human fetal testis. If confirmed, health policies to prevent male reproductive problems should not only target adult men, but also pregnant women and their children.

Testicular cancer trends as 'whistle blowers' of testicular developmental problems in populations

Recently a worldwide rise in the incidence of testicular germ cell cancer (TGCC) has been repeatedly reported. The changing disease pattern may signal that other testicular problems may also be increasing. We have reviewed recent research progress, in particular evidence gathered in the Nordic countries, which shows strong associations between testicular cancer, undescended testis, hypospadias, poor testicular development and function, and male infertility. These studies have led us to suggest the existence of a testicular dysgenesis syndrome (TDS), of which TGCC, undescended testis, hypospadias/disorders of sex differentiation and male fertility problems may be symptoms with varying penetration. In spite of their fetal origin, most of the TDS symptoms, including TGCC and poor semen quality, can only be diagnosed in adulthood. Data from a Danish-Finnish research collaboration strongly suggest that trends in TGCC rates of a population may be 'whistle blowers' of other reproductive health problems. As cancer registries are often of excellent quality - in contrast to registries for congenital abnormalities - health authorities should consider an increase in TGCC as a warning that other reproductive health problems may also be rising.

Spermatogenesis in the contralateral testis of patients with testicular germ cell cancer: histological evaluation of testicular biopsies and a comparison with healthy males

OBJECTIVE

To assess histologically signs of testicular dysgenesis (TD) in the contralateral testes of patients with testicular germ cell tumours (GCTs) and to compare these findings with the spermatogenetic quality in healthy men, as the contralateral testis is considered to be involved with dysgenetic features such as poor sperm production, and accordingly, GCTs are hypothesized to be part of the 'TD syndrome' (TDS). One testicular biopsy is thought to represent spermatogenesis in the entire testis. We evaluated this view by using testicular two-site biopsies.

PATIENTS AND METHODS

2318 patients with testicular GCT had a contralateral testicular two-site biopsy. Testicular biopsies taken on forensic autopsy from 1388 presumably healthy men served as controls. Spermatogenesis was rated histologically according to a modified Johnsen score. Clinical factors were recorded to explore associations with reduced spermatogenesis. Differences in spermatogenesis scoring results among two-site biopsies were noted. Statistical analysis involved Wilcoxon-Mann-Whitney and Jonckheere-Terpstra tests for comparing patients and controls, and for studying associations with clinical factors. Classification and regression-tree analysis was used to explore multivariate associations.

RESULTS

Histologically, patients had significantly poorer spermatogenesis than healthy men. Clinically, hypospermatogenesis was significantly associated with testicular atrophy, undescended testes, male infertility, and advanced clinical stage; 5.4% of cases (95% confidence interval 4.43-6.27) had discordant findings of >2 points on double biopsy and 9.8% had differences of 1 point. Discordance was significantly associated with poor spermatogenesis and testicular atrophy.

CONCLUSIONS

We confirmed histologically that there is markedly reduced spermatogenesis in the contralateral testes of patients with GCT. This result lends credence to the view that GCT is part of the so-called TDS. But as hypospermatogenesis is associated with advanced clinical stage, impairment of sperm production might at least partly be acquired secondary to the endocrine activity of GCT. There were clinically relevant discordant results on double biopsy in 5.4%, predominantly in infertile patients and in atrophic testes. Thus the histological evaluation of male infertility is best done by multiple biopsies.

Coordinated European investigations of semen quality: results from studies of Scandinavian young men is a matter of concern

For many years it has been acknowledged that Danish and Norwegian men have one of the highest risks in the world for testicular cancer in sharp contrast to neighbouring Baltic men from Finland, Estonia and Lithuania. As an association between poor semen quality and testicular cancer has been established, it was suggested that men from high-risk testicular cancer areas would be more likely to have poor semen quality. However, previous studies were not able to elucidate this question due to their retrospective nature. In prospectively designed and strictly controlled studies of fertile men, the existence of regional differences in semen quality was confirmed. In addition, studies of men from the general populations were undertaken and a similar regional difference in semen quality was detected. Men from the eastern part of the Nordic-Baltic area had better semen quality than men from the western part. These findings parallel the incidence of testicular cancer in these regions. Approximately 20% of young men from Norway and Denmark had sperm concentrations below the World Health Organization reference level of 20 x 10(6) spermatozoa/mL, and approximately 40% had <40 x 10(6) spermatozoa/mL which, according to recent publications, may be the 'threshold' below which fecundity declines. In Denmark, the situation is of concern and a continued surveillance of semen quality in young men was established in 2001 by a government-supported programme.

Is human fecundity declining?

Summary The decreasing trends in fertility rates in many industrialized countries are now so dramatic that they deserve much more scientific attention. Although social and behavioural factors undoubtedly play a major role for these trends, it seems premature, and not based on solid information, to conclude that these trends can be ascribed to social and behavioural changes alone. There is evidence to suspect that changing lifestyle and increasing environmental exposures, e.g. to endocrine disrupters, are behind the trends in occurrence of male reproductive health problems, including testis cancer, undescended testis and poor semen quality. These biological factors may also contribute to the extremely low fertility rates. However, the necessary research is complex and requires non-traditional collaboration between demographers, epidemiologists, clinicians, biologists, wild life researchers, geneticists and molecular biologists. This research effort can hardly be carried out without major support from governments and granting agencies making it possible to fund collaborative projects within novel research networks of scientists.

Effects of gonadotropin-releasing hormone analogs on cis-platinum-induced spermatogenic damage

In order to test the hypothesis that pretreatment with gonadotropin-releasing hormone (GnRH) analogs might ameliorate cytotoxic drug-induced testicular damage, mature male Wistar rats were pretreated for 2 weeks with a GnRH superactive agonist or a pure GnRH antagonist prior to, and for 1 week after, a 5 mg/kg intraperitoneal dose of cis-platinum. Despite inhibition of testicular function by both GnRH analogs prior to cis-platinum administration, there was no evidence of protection or enhanced recovery of spermatogenesis at 6 and 12 weeks after cis-platinum treatment, and spermatogenesis was significantly further depressed at both time-points by both GnRH agonist and antagonist pretreatment. This suggests that pretreatment with GnRH analogs in the rat does not protect spermatogenesis from cis-platinum-induced testicular damage within up to two spermatogenic cycles and that hypogonadism at the time of cytotoxic drug treatments may aggravate testicular damage.

Testicular cancer and fertility

Before treatment, a little over one-half of patients with testicular cancer have fathered children, while one-fifth have a history of sterility. Radiotherapy with a gonadal dose of less than 1.5 Gy seems to do little permanent damage to fertility. Following cisplatin-based combination chemotherapy, a number of conceptions have been reported. The newer regimens affect spermatogenesis less than earlier ones due to a lower toxicity of the drugs and shorter duration of the treatment. New modifications of retroperitoneal lymphadenectomy may save ejaculatory ability in over one-half of the patients. It is uncertain whether this procedure is less detrimental to fertility than the cisplatin-based combination chemotherapy. Even though semen quality is often poor before treatment, cryopreservation of semen should be considered since in vitro fertilization may be successful even with very poor semen quality. There are no indications in the literature of permanent adverse genetic effects of the treatment.