Cryptorchidism natural history, complications and prognosis
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Saumya Easaw, M.B.B.S.[2]
Complications
Infertility
Prevalence
Many men who were born with undescended testes have reduced fertility, even after orchiopexy in infancy. The reduction with unilateral cryptorchidism is subtle, with a reported infertility rate of about 10%, compared with about 6% reported by the same study for the general population of adult men.
The fertility reduction after orchiopexy for bilateral cryptorchidism is more marked, about 38%, or 6 times that of the general population. The basis for the universal recommendation for early surgery is research showing degeneration of spermatogenic tissue and reduced spermatogonia counts after the second year of life in undescended testes. The degree to which this is prevented or improved by early orchiopexy is still uncertain.
Pathophysiology
At least one contributing mechanism for reduced spermatogenesis in cryptorchid testes is temperature. The temperature of testes in the scrotum is at least a couple of degrees cooler than in the abdomen. Animal experiments in the middle of the 20th century suggested that raising the temperature could damage fertility. Some circumstantial evidence suggests tight underwear and other practices that raise testicular temperature for prolonged periods can be associated with lower sperm counts. Nevertheless, research in recent decades suggests that the issue of fertility is more complex than a simple matter of temperature. It seems likely that subtle or transient hormone deficiencies or other factors that lead to lack of descent also impair the development of spermatogenic tissue.
The inhibition of spermatogenesis by ordinary intra-abdominal temperature is so potent that continual suspension of normal testes tightly against the inguinal ring at the top of the scrotum by means of special "suspensory briefs" has been researched as a method of male contraception, and was referred to as "artificial cryptorchidism" by one report.
An additional factor contributing to infertility is the high rate of anomalies of the epididymis in boys with cryptorchidism (over 90% in some studies). Even after orchiopexy, these may also affect sperm maturation and motility at an older age.
Later Cancer Risk
One of the strongest arguments for early orchiopexy is prevention of testicular cancer. About 1 in 500 men born with one or both testes undescended develops testicular cancer, roughly a 4- to 40-fold increased risk. The peak incidence occurs in the 3rd and 4th decades of life. The risk is higher for intra-abdominal testes and somewhat lower for inguinal testes, but even the normally descended testis of a man whose other testis was undescended has about a 20% higher cancer risk than those of other men.
The most common type of testicular cancer occurring in undescended testes is seminoma. It is usually treatable if caught early, so urologists often recommend that boys who had orchiopexy as infants be taught testicular self-examination, to recognize testicular masses and seek early medical care for them. Cancer developing in an intra-abdominal testis would be unlikely to be recognized before considerable growth and spread, and one of the advantages of orchiopexy is that a mass developing in a scrotal testis is simply far easier to recognize than an intra-abdominal mass.
Although orchiopexy makes cancer more easily recognizable at an early stage, whether early orchiopexy actually reduces the chance of developing cancer remains a subject of controversy. As with infertility, the causes of cancer associated with cryptorchidism are not known. Most evidence suggests the cancer risk is due to an inherent abnormality of the undescended testis rather than to the ability of an abdominal location to cause cancer in an otherwise normal testis.
The risk of malignancy in the undescended testis is 4 to 10 times higher than that in the general population and is approximately 1 in 80 with a unilateral undescended testis and 1 in 40 to 1 in 50 for bilateral undescended testes. The peak age for this tumor is 15–45 yr. The most common tumor developing in an undescended testis is a seminoma (65%); in contrast, after orchiopexy, seminomas represent only 30% of testis tumors.
Prognosis
Inheritance and Recurrence Risk
A small percentage of cases of isolated cryptorchidism are familial. It has been reported that about 4% of fathers and 6-10% of brothers of affected boys have also had cryptorchidism. Few specific genes associated with isolated cryptorchidism have been identified.
In contrast, many of the genes causing some of the intersex conditions associated with androgen or AMH deficiency or insensitivity have been identified, and genetic counseling to explain recurrence risk to families is appropriate.
A new study shows that pregnant women who drink caffeine (at least 3drinks per day*) will increase the risk of cryptorchidism.