Pettersson A et al. (2007) Age at surgery for undescended testis and risk of testicular cancer. N Engl J Med 356: 1835–1841

Surgical treatment for cryptorchidism before puberty decreases the risk of testicular cancer, according to a large Swedish cohort study.

Cryptorchidism is a known risk factor for testicular cancer, but the relationship between age at treatment and testicular cancer risk is controversial. To address this issue, Pettersson and colleagues from the Karolinska Institutet in Stockholm reviewed the records of almost 17,000 Swedish men who underwent surgery to correct cryptorchidism before the age of 20 years. Patients were followed for a total of 209,984 person-years, with follow-up starting 1 year after surgery to reduce the risk of including patients who already had testicular cancer. A nationwide cancer registry was used to monitor the occurrence of testicular cancer in the cohort, ensuring complete follow-up. The relative risk of testicular cancer in the cohort was estimated and compared with that in the general population.

In total, 56 patients in the cohort developed testicular cancer during the follow-up period. Patients who underwent surgery before the age of 13 years had a relative risk of 2.23 (95% CI 1.58–3.06) of developing testicular cancer compared with the Swedish general population, whereas those who underwent surgery after the age of 13 years had a relative risk of 5.40 (95% CI, 3.20–8.53).

Although the risk of testicular cancer is thought to be determined before birth, these findings suggest that puberty may be another important event in testicular carcinogenesis. This study supports the current recommendation that patients with cryptorchidism are treated early.