Testicular cancer affects fewer than six out of 100,000 American men – that’s the good news. The bad news is that the disease is on the rise in young Hispanic Americans. A study published Monday in the journal Cancer found that between 1992 and 2010, the annual incidence of testicular cancer in 15- to 39-year-old Hispanic whites increased 58 percent, while in the same 19-year time period, the incidence among non-Hispanic white young adults increased 7 percent.
The study suggests that this new trend may be a sign that something is changing in the lifestyle or environment of Hispanic boys and young men, according to co-author Dr. Stephen Schwartz, an epidemiologist in the Public Health Sciences Division of Fred Hutchinson Cancer Research Center, who contributed to the data analysis of the study.
It’s no surprise that Hispanic Americans are the fastest growing ethnic group in the nation. In fact, the Hispanic population in the United States has been on the rise for many years. According to 2010 census data, there are now more than 50 million U.S. residents who can claim Hispanic American status.
So, it’s reasonable to ask: Are the growing numbers of Hispanic men with testicular cancer simply a reflection of the rise in Hispanic Americans overall? Researchers involved in the study examined the data in such a way that population increase alone could not cause the trends they saw in the rising incidence of testicular cancer among Hispanic-American men.
“As part of the project, we looked at several possible explanations, including whether there has been better classification of who is Hispanic among [testicular cancer] cases … or whether there has been a worsening undercounting of Hispanics in the population,” Schwartz said. “Neither of these [issues] seemed to be occurring in a way that would cause the trends that we saw.”
Highest cure rate of any solid tumor
When testicular cancer appears, it most often targets adolescents and young adults between the ages of 15 and 39, but older men can also be affected. It has the highest cure rate of any solid tumor, with a five-year survival rate of 95 percent or greater.
Testicular cancer has few known risk factors, and most of those issues cannot be altered. According to the American Cancer Society, a man can be at increased risk because of an undescended testicle (a condition known as cryptorchidism), HIV infection or AIDS, carcinoma in situ (a form of precancer), race and taller height.
The positive association between physical height and risk for testicular cancer may be due to any of the many environmental factors that influence growth in infancy, childhood, and adolescence. The new study suggests that the disease might be a sort of “canary in the coal mine,” possibly signaling changes in diet.
“The connection between early life nutrition and adult height is clear,” said Schwartz, meaning that better nutrition in childhood is associated with greater adult height. He said, however, that “the effect [of greater height on risk for testicular cancer] could also be just a surrogate for some aspect of the environment that these men experienced when they were young.”
One possible cause is the improvement in access to nutritious, more expensive foods. This situation may sound like a contradiction – that improved nutrition could lead to increased cancer – but such changes in diet could also include increased consumption of certain chemicals or certain foods that may contribute to increased risk of some cancers.
The rise in obesity and the health effects of pollutants in the environment have already been documented. For example, said Schwartz, “there are chemicals which are known to aggregate in animal-based products. These products tend to be the more expensive foods.” The mechanism between greater adult height and higher risk for testicular cancer calls for more research, he said.
Testicular cancer on the rise overall
Research also indicates that the incidence of testicular cancer has been rising overall in many ethnic groups during the past few decades. The Asian-American population is the only group that has not displayed higher rates of testicular cancer.
This latest increase in rates within Hispanic-American men raises a lot of questions. “There are clearly things changing in the population that are connected to the time when we are born,” Schwartz said. “There is something about men being born more recently that is contributing to the increased risk [of testicular cancer] in various groups.”
Dr. Rebecca Johnson, former medical director of the Adolescent and Young Adult Oncology Program at Seattle Children’s Hospital, led the study.
Solid tumors, such as those of the testicles, are the focus of Solid Tumor Translational Research, a network comprised of Fred Hutchinson Cancer Research Center, UW Medicine and Seattle Cancer Care Alliance. STTR is bridging laboratory sciences and patient care to provide the most precise treatment options for patients with solid tumor cancers.
Joely Johnson Mork is a Seattle-based freelance health and science writer/editor whose work has appeared in numerous consumer health books, as well as in Prevention and TIME. Her personal essays have been heard on NPR. Mork has a master’s degree in community health education and is a certified yoga instructor.