Houston, Texas, USA : Undescended testes in boyhood is associated with an increased risk of testicular cancer and male infertility, and decreased paternity, researchers report. The researchers provide new evidence to support current guidelines for orchidopexy before age 18 months to decrease the risk of future testicular cancer and infertility.
Led by the University of Sydney researchers and published today in The Lancet Child & Adolescent Health, this is the first population-based cohort study to assess both adult fertility and cancer risk after surgical correction (orchidopexy) for undescended testes in early childhood. The procedure moves an undescended testicle into the scrotum and permanently fixes it there.
“In addition to an increased risk of testicular cancer, we found that boys with undescended testes had decreased paternity and increased use of assisted reproductive technologies for infertility in later life,” said the University of Sydney’s Professor Natasha Nassar, the study’s senior author.
“The study provides new evidence to support international guidelines recommending surgery before 18 months for boys with undescended testes to reduce the risk of both testicular cancer and infertility later in life.”
But compliance with these guidelines remains poor with almost half of all boys with undescended testes in Australia and more than three-quarters worldwide being operated on after 18 months, say the research team from the University of Sydney, Curtin University and the Telethon Kids Institute.
“Before this study, there was no evidence-based information on the impact of early surgery on the future risk of testicular cancer and infertility in adult males,” said study leader, Dr Francisco Schneuer of the University of Sydney.
“Early diagnosis, ongoing examination and monitoring by parents and health practitioners and timely referral to surgery of boys with undescended testes is important to ensure adherence with guidelines.
“Early surgery can reduce the risk of malignancy and male infertility, and ultimately has the potential to reduce future adult male reproductive disorders.”
This is a population-based cohort study of 350,835 boys born in Western Australia between 1970 and 1999. The cohort was followed until 2016 by linking to data registries for hospital admissions, birth defects, cancer, and assisted reproductive technologies.
“The male genital anomalies hypospadias and undescended testes have been linked to adult male reproductive disorders, testicular cancer, and decreased fertility. Few population-based studies have evaluated their effects on adult fertility outcomes and, in the case of undescended testes, the importance of early corrective surgery (orchidopexy).
We did a population-based cohort study of all liveborn boys in Western Australia in 1970–99, and followed them up until 2016 via data linkage to registries for hospital admissions, congenital anomalies, cancer, and assisted reproductive technologies (ART). Study factors were hypospadias or undescended testes, and study outcomes were testicular cancer, paternity, and use of ART for male infertility. Cox regression was used to calculate hazard ratios (HRs) for the associations between genital anomalies and testicular cancer or paternity, and log-binomial regression was used to calculate relative risks (RRs) for the associations between genital anomalies and use of ART.” The researchers wrote.
Key study findings
- Boys with undescended testes had 2.4 times the risk of adult testicular cancer compared to unaffected boys
- The risk of testicular cancer increased by 6 percent with each 6-month increase in age at time of surgery (orchidopexy)
- Boys with undescended testes had a 20 percent lower chance of paternity in adulthood compared to unaffected boys, and were more than twice as likely to use assisted reproductive technology for infertility as adults.
Funding : National Health and Medical Research Council and Sydney Medical School Foundation.
Male reproductive disorders increasing worldwide
Undescended testes is the most common reproductive birth defect in infant boys. One in 100 boys are affected and will require surgery
Testicular cancer affects young men aged 20-40 years, is the second most common cancer in young men and while rare, has increased by 50 percent in the last 30 years
Male infertility is a major challenge, with 5-10 percent of men worldwide being infertile.
As a male fetus develops, the testes form in the abdomen, just as the ovaries form in a female. During the third trimester, somewhere between weeks 26 and 34, if all goes well, the testicles descend into the scrotum, and they get checked for the first time as soon as the baby is born, as part of the newborn exam done in the delivery room, and again in the nursery.
When the delivery room nurse or the pediatrician tells the parents, “He has 10 fingers, 10 toes,” or the equivalent, that person has also checked the newborn scrotum for two pea-size testes, hanging down. Back in the days when medical notes were handwritten, this was universally denoted by two downward-pointing arrows, side by side: left and right, down and down.
About 3 percent of full-term male infants, though, don’t have both testes descended at birth, a condition called cryptorchidism (crypto means hidden, and orchis is Greek for testicle, and the source of the word orchid, supposedly because of the shape of certain orchid roots). The numbers are much higher in premature infants, who may be born before the testes have moved. In other babies, the testes may be down at birth, but one or both may retract back up later on.
If testes aren’t down in the scrotum as a boy grows, they are less likely to stay healthy and functional — there may be fertility problems later on in life, and there’s even a risk of testicular cancer. That’s why pediatricians check this so compulsively, in the delivery room, in the nursery, and at every checkup, and it’s one reason experts emphasize the importance of including the genital exam every time a boy has a physical.
Many undescended testes do descend all by themselves, in the first months of a baby boy’s life, but if they haven’t come down by the time a child is 6 months old, the baby needs a urologic surgical procedure. This happens in as many as 1 percent of boys, so it’s a relatively common surgery.
“If it doesn’t come down by 6 months, it’s not going to come down on its own,” said Dr. Thomas F. Kolon, a pediatric urologist at Children’s Hospital of Philadelphia and professor of urology at the University of Pennsylvania School of Medicine. He is the lead author on the American Urological Association guidelines for the evaluation and treatment of cryptorchidism. “Start thinking of therapy by 6 months and really do something by 18 months.”
In general, he said, the boys with unilateral cryptorchidism — one testis descends, the other doesn’t — do very well, but “the bilaterals take more of a hit.”
Although the risk of testicular cancer is higher in boys with cryptorchidism, it still remains a rare disease; to monitor themselves, adolescents at risk should be taught to do a monthly testicular self-exam, looking for changes that might suggest cancer, Dr. Kolon said.
The surgery, called orchiopexy, is done under general anesthesia and is more complicated if the testes are higher up. If they are up above the scrotum but still palpable, the surgeon will make a small incision in the groin, free the testis, and then another small incision in the scrotum, where it will be anchored in place. If the testis cannot be felt at all, the surgeons may do a laparoscopic procedure, putting a camera in through the baby’s belly button, and if they find the testes in the abdomen, there may be a two-stage operation, first freeing up the testis and then, six months later, in another procedure, bringing it down into the scrotum.
In some newborns, the absence of testes in the scrotum is part of a larger and sometimes more serious syndrome, and those children may need additional medical attention.
On the other hand, many of the baby boys that pediatricians refer to urology because of undescended testicles actually turn out to have what are called retractile testes, which do not need surgery, said Dr. Aseem R. Shukla, a pediatric urologist at the Children’s Hospital of Philadelphia and an associate professor of urology at the University of Pennsylvania School of Medicine. “If you’re in a cold room, the pediatrician’s hands are cold, the baby very ticklish,” he said, then the cremaster muscle, which connects to the cord of the testicle, raises it up.
There are also some cases where boys are born with their testes descended, but they later retract back up, again putting them at risk. Dr. Shukla said that these cases are often missed if pediatricians skip the genital exam in older boys. “It’s too often missed for a long period of time, a boy doesn’t want to be checked down there, the pediatrician doesn’t want to put him through it,” he said. “It needs to be part of every annual physical exam, not something to be forgotten. We find undescended testicles all too often.”