Genetic Risk Factors for Testicular Cancer

In 2022, the American Cancer Society estimates clinicians will diagnose 9,910 new cases of testicular cancer in the United States. This figure is not huge—only about 1 in 250 men will develop testicular cancer at some point during their lifetime.

The disease typically affects men between the ages of 15 and 49, and accounts for just 1 percent of all cancers that occur in men. As well as being one of the less common cancers, treatment is often successful for testicular cancer. Therefore, the lifetime risk of dying from this type of cancer is very low.

Despite the relatively favorable statistics, it's still useful to know the risk factors, the signs and symptoms, and the genetic component of testicular cancer.

Some of the risk of developing testicular cancer comes from DNA passed down from parents, according to Justin Houman, M.D., a urologist and men's health specialist at Tower Urology in Los Angeles.

"We know that having a father or brother with testicular cancer increases your risk," he said. "However, only a small number of testicular cancers occur in families.

"Most men with testicular cancer experience this spontaneously and do not have a family history of the disease," he added.

Katherine Nathanson, M.D., the Pearl Basser Professor for BRCA-Related Research at the Abramson Cancer Center of the University of Pennsylvania in Philadelphia, explained genetic risk in a little more detail.

"It's been well established that there is a very high relative/genetic risk for men who have had a sibling or father with testicular cancer," she said. "The relative risk for testicular cancer is higher than any other cancer type."

For example, if your father had testicular cancer, you're about four to six times more likely to develop it than someone with no family history of the condition, Nathanson said. This risk of getting the disease increases to eight times more likely if you have a brother who had it.

But if there is a higher risk for men who have a family member with testicular cancer, why aren't there more testicular cancer cases?

"That is because the absolute risk is still very low," Nathanson responded.

Another group at higher risk of testicular cancer is men who have a history of cryptorchidism, an undescended testicle.

"They are particularly at risk if the testicle remains undescended," Nathanson said.

Around 3 percent to 5 percent of boys are born with cryptorchidism. The testicles typically descend into the scrotum during the first year of life, but this does not occur in some boys.

Houman said it is believed that the risk of cancer is not directly related to a testicle failing to descend. Rather, this represents an abnormality in the testicle that makes cancer more likely.

Although testicular cancer is very treatable, it is always easier to treat when detected early. That being said, there aren't any official guidelines, such as increased screening, for men who have a family history of testicular cancer or cryptorchidism, Nathanson said. However, males are advised to self-check their testicles regularly from puberty onward, especially if they have either of the two main risk factors.

By checking your testicles regularly, you get to know what they should look and feel like, so you can recognize anything abnormal. They should feel smooth and firm but not hard. Macmillan Cancer Support, a charity in the United Kingdom, suggests these steps for checking your testicles:

1. Hold your scrotum in the palm of your hand.
2. Massage or roll each testicle between your fingers and thumb.
3. You should feel for:

• lumps, bumps or swelling
• anything unusual or any distinctive changes
• differences between the two testicles

Be aware that it's normal for your testicles to differ in size slightly and for one to hang lower than the other. If you do find a lump or swelling, it is not necessarily testicular cancer. However, you should always get any abnormalities checked by a doctor as soon as possible to make sure.

"There is currently no genetic testing for testicular cancer," Nathanson said. "However, I think we will reach the point where a clinical genetic test, like encompassing variation in multiple genes, will identify men at high risk of testicular cancer."

According to Houman, although family history increases your chance of testicular cancer, scientists have not identified a specific gene linked to the disease.

"As a scientific community, we are working to identify which exact genes are responsible for testicular cancer," he said.

Research in this area is ongoing to better understand the genetic factors associated with testicular cancer. More research is necessary for doctors to establish all the genetic interactions that contribute to the development of testicular cancer.