STOCKHOLM -- The risk of testicular cancer can be reduced if surgery for undescended testicles takes place before puberty, according to researchers here.
STOCKHOLM, May 2 -- The risk of testicular cancer can be reduced if surgery for undescended testicles takes place before puberty, according to researchers here.
In a large Swedish cohort, the risk of cancer later in life for boys who had surgery before age 13 was less than half than seen in men and boys who had the operation when they were older, said Andreas Pettersson, M.D., of the Karolinska Institute.
The results "also suggest that the ectopic position of the testis is a factor in the development of testicular cancer," Dr. Pettersson and colleagues reported in the May 3 issue of the New England Journal of Medicine.
Undescended testis -- also known as cryptorchidism -- occurs in 2% to 5% of full-term male infants and is associated with impaired fertility and testicular cancer, the researchers noted.
The risk of cancer is increased between two and eight times in men who have had cryptorchidism, they said, and up to 10% of all men with testicular cancer have a history of undescended testis.
Surgery to correct the condition can be performed as early as six months, but it had not been clear whether early surgery has any effect on the risk of cancer, the researchers said.
To clarify the issue, they looked at 16,983 Swedish men and boys who were diagnosed with cryptorchidism from 1965 through 2000, using data from the country's cancer registry and nationwide hospital discharge records.
All told, the men were followed for a mean of 12.4 years. During that time, 56 developed testicular cancer. Only 20 cases would have been expected based on the incidence rate in the general Swedish population.
That gave a standardized incidence ratio of 2.75 for testicular cancer for men with cryptorchidism, compared with the general population, the researchers said.
When the cohort was divided into those who had had surgery before they reached the age of 13 and those who were 13 or older at the time of the operation, analysis showed:
A within-cohort analysis showed that the hazard ratio for cancer was 1.99 for those 13 or older at surgery, compared with those who had the operation at a younger age.
The effect of cryptorchidism on testicular cancer risk has been controversial, with some arguing that the risk factors are set in utero or early in life, the researchers said.
Indeed, because the risk was increased in the entire cohort, compared with the general population, not all of the risk can be associated with the ectopic position of the testis at puberty, they said, and some other factors must be at play.
But, they concluded, the current results "suggest that puberty, here defined arbitrarily as beginning at the age of 13 years, is another crucial event in testicular carcinogenesis."