Testicular cancer is a relatively uncommon type of cancer that originates in the testicles, which are part of the male reproductive system. While it is not frequently diagnosed, it is often highly treatable, particularly when detected in its early stages. The precise reasons why testicular cancer develops are not fully understood, but researchers have identified several factors that can increase a person’s likelihood of developing this condition.
Medical and Developmental Conditions
An undescended testicle, known as cryptorchidism, is a risk factor for testicular cancer. Normally, testicles descend into the scrotum before birth, but in about 3% of boys, one or both do not make this journey. The risk of developing cancer is elevated even if surgery (orchiopexy) is performed to correct the position, though early surgery may reduce the risk. This increased risk stems from an underlying abnormality in the testicle itself, rather than solely its location. The higher the testicle’s position, such as remaining in the abdomen, the greater the risk.
Other developmental conditions also correlate with an increased likelihood of testicular cancer. Klinefelter syndrome, a genetic condition where males have an extra X chromosome, can lead to abnormal testicular development and a higher propensity for germ cell tumors. Additionally, intratubular germ cell neoplasia (IGCN) is a precursor for most testicular germ cell tumors. These abnormal cells can develop invasive potential during puberty due to hormonal changes.
Personal and Family History
A personal history of testicular cancer in one testicle increases the likelihood of developing it in the other. Approximately 3% to 4% of individuals who have been successfully treated for cancer in one testicle will later develop it in the remaining testicle. This risk is distinct from genetic predispositions, emphasizing the importance of ongoing monitoring for those with a prior diagnosis.
Genetic connections also play a role, as a family history of testicular cancer can elevate an individual’s risk. Having a brother with testicular cancer increases the risk by eight to twelvefold. If a father has had testicular cancer, the risk is about two to four times higher. While a small percentage of cases appear to have a genetic link, most men diagnosed with testicular cancer do not have a family history of the disease.
Demographics and Health Status
Age is a demographic factor, with testicular cancer disproportionately affecting adolescents and young men. Most diagnoses occur between the ages of 15 and 35, making it the most common cancer in this age group. Although less common, cases can still arise outside this typical range, including in infants and older men.
Race and ethnicity also show varying incidence rates for testicular cancer. White men have a higher risk compared to men of other racial backgrounds, with rates about four to five times greater than Black men and approximately two times higher than Asian-American men. The reasons behind these disparities are not yet fully understood. Individuals with human immunodeficiency virus (HIV) infection, particularly those with AIDS, also have a slightly increased risk of developing testicular cancer.
Factors Not Linked to Testicular Cancer
Several common beliefs about the causes of testicular cancer are not supported by scientific evidence. An injury to the testicles, for instance, has not been shown to increase the risk of developing this cancer. Similarly, activities such as cycling or horseback riding do not increase the risk.
Wearing tight underwear has also been a subject of speculation, but there is no evidence to suggest it contributes to testicular cancer development. Having undergone a vasectomy does not increase a person’s risk of testicular cancer. These factors are often mistakenly linked to the disease, but current research indicates no causal connection.