Testicular cancer is noted to be the most common malignant cancer among men aged 15-44 years.1 Despite its being the most common, studies show testicular cancer accounts for only 1% of cancers among men over all. Although several risk factors have been identified, there are no clear direct causes of testicular cancer, and its incidence is on the rise.
In 2004 and again in 2010, the United States Preventive Services Task Force (USPSTF) determined that routine screening in asymptomatic males for testicular cancer either by self-exam or ultrasound did not yield better health outcomes.1 A 2015 study found that testicular cancer incidence in males over 15 years in the United States rose from 5.7/100,000 in 1992 to 6.8/100,000 in 2009, with a significant annual percentage change of 1.1% (P less than .001).2 Thankfully, mortality rates have declined since the 1970s because of the improvements made in chemotherapy regimens.3
Although several studies have investigated this issue, few have been able to determine an exact cause and effect, but several theories have been put forth as likely causes in the rising rates. Most of the established risk factors – such as cryptorchidism, age, race, and exposure to estrogen-mimicking chemicals in utero – have been well described in the literature, but what other factors are affecting our youth?
Increase in sedentary lifestyle is believed to play a role, mostly in relationship to the increase in heat exposure.4 As with cryptorchidism, the elevated temperatures associated with internal body temperatures and testicular exposure to it for extended time periods makes this association reasonable.
Dietary factors have shown a strong relationship to development of testicular cancer, as well. High-fat diets and large intake of dairy products were particularly implicated and correlated regionally with the highest incidences.5 Highest rates of testicular cancer are noted to be in Denmark and other European countries in which there is a high intake of dairy products.
Physical activity such as horseback riding, bicycle riding, and motorcycle riding had varied results when studied, but repeated low-level trauma has been associated with an increased risk of testicular cancer.6
Occupations that have repeated exposure to high-heat environments, such as fireman and factory workers, also showed elevated incidences. Aircraft maintenance and handling of heavy metal and pesticides also have showed a correlation. A substantial amount of evidence indicates that environmental pollutants with estrogenic or antiandrogenic activity are associated with increasing incidence of testicular cancer.4
Genetics have the strongest correlation as a risk factor. It has been well documented that there is an eight- to tenfold increase in risk if a brother has been diagnosed with testicular cancer and a four- to sixfold in risk for the son if a father had testicular cancer. Down syndrome also showed increased genetic risk for testicular cancer.3
Although mortality rates are declining and screening for testicular cancer is not indicated, it is important to remember the risk factors and consider it in the differential diagnosis of a symptomatic male given 26%-56% of newly diagnosed testicular cancer patients were wrongly diagnosed initially.1 Dietary guidance also can be helpful for patients who do have increased risk factors; have them avoid high fat diets and excessive dairy intake. Make patients aware that testicular cancer is most common in younger men, and if they note any changes in their testicle, they should seek medical attention.
Dr. Pearce is a pediatrician in Frankfort, Ill. She said she had no relevant financial disclosures. Email her at.