Boys with isolated cryptorchidism have a three-fold increased risk of developing testicular cancer later in life, a meta-analysis published in Archives of Disease in Childhood has found.

A comprehensive literature search identified more than 700 papers, of which just 12 met the quality inclusion criteria for analysis. Of these, nine were case-control studies (2,281 subjects and 4,811 controls). The three cohort studies, which used central registries in Sweden, Denmark and the UK, identified 345 cases of testicular cancer in a total cohort of more than two million subjects followed from childhood.

The studies were conducted principally among Caucasian males. The criteria used for diagnosis were wide, however syndromes where testicular cancer is a feature (infertility and hypospadias for example) were excluded.

All 12 studies identified a significant risk association between cryptorchidism and testicular cancer.

The relative risk (RR) range across the studies was 1.47-9.0. For case-control and cohort studies it averaged 2.47 (95% CI:1.91-3.18, P < 0.0001) and 3.77 (95% CI:2.65-5.37, P = 0.01), respectively. The total overall RR was 2.9 (95% CI:2.21-3.82, P < 0.0001).

Definitions of cryptorchidism range from a simple retractile testis to maldescent, with the gonad located in the abdomen or inguinal canal.

The analysis was not able to stratify risk with varying grades of maldescent, or whether surgical interventions had been undertaken.

The current incidence of testicular cancer in the UK is thought to be around 6.9/100,000 men. A three-fold increase in risk implies it may affect around 1:5,000 men with a history of cryptorchidism.

The authors conclude their discussion by questioning whether the risk is significant enough to warrant regular follow-up. Screening of course is a separate issue and this is a question that the present study could not answer.

Dr Chris Barclay

• Lip SZL, Murchison LED, Cullis PS et al. A meta-analysis of the risk of boys with isolated cryptorchidism developing testicular cancer in later life. Arch Dis Child 2012;00:1-7.doi10.1136/archdischild -2012-302051