Testicular Cancer Increasing in Young Hispanic Americans

Fran Lowry

July 15, 2014

Rates of testicular cancer have risen dramatically in the past 2 decades in young Hispanic Americans, but not in non-Hispanic white Americans.

This indicates the need for increased awareness about testicular germ cell tumors (TGCT), Stephen M. Schwartz, PhD, MPH, from the Fred Hutchinson Cancer Research Center in Seattle, and colleagues report.

Their research was published online July 14 in Cancer.

The study was prompted by the fact that the Hispanic population has grown rapidly in the past couple of decades in the United States, particularly young males 15 to 39 years of age, which is the range when TGCT most commonly occurs.

"Clinicians can expect to see a substantial rise in the number of Hispanic TGCT patients," Dr. Schwartz told Medscape Medical News.

"We hope that there will be increased awareness that TGCT is not just a problem of non-Hispanic white men, which heretofore was the case, and that research should be done to understand why rates of TGCT have been increasing," he explained.

"We knew that TGCT incidence had risen dramatically in other racial and ethnic groups, but there had not been any thorough examination of possible trends in Hispanic TGCT incidence," Dr. Schwartz said. "In large part, this was because it has only been since 1992 that the American data allowed us to distinguish between Hispanic and non-Hispanic heritage individuals."

The researchers analyzed trends in testicular cancer rates in 2 datasets from the Surveillance, Epidemiology, and End Results (SEER) program. The dataset from 1992 to 2010 sampled 15% of the American population, and the dataset from 2000 to 2010 sampled 28% of the population.

The annual incidence of testicular cancer in 15- to 39-year-old Hispanic whites increased 58% from 1992 to 2010 — from 7.18 cases per 100,000 to 11.34 cases per 100,000 (P < 1 × 10⁹).

Incidence rates increased in metropolitan areas for both seminoma and nonseminoma subtypes of testicular cancer and for all disease diagnosed, regardless of stage.

The incidence of testicular cancer in non-Hispanic whites increased 7% from 1992 to 2010 — from 12.41 to 13.22 per 100,000. In the 2000 to 2010 dataset, no significant trends in incidence were observed in non-Hispanic whites.

Why the Increase in Hispanic but Not White Patients?

Previous studies have shown that the incidence rates of testicular cancer increased substantially in white Americans from the mid-1970s to the early 2000s, and in black Americans from the late 1980s to the early 2000s, Dr. Swartz reported.

"We don't have data that allowed distinguishing Hispanic whites from non-Hispanic whites during the same time that rates were increasing in these other groups, so we can't be sure that there were not years in which the rates were increasing in all 3 groups. All we know at this point is that from the early 1990s until 2010, the rise in TGCT rates among Hispanic whites, 58%, substantially outpaced that of non-Hispanic whites, which was little or none," he said.

"The most we can conclude is that something in the lifestyle or environment to which Hispanic males in the early 1990s to 2010 have been exposed — possibly as far back as when they were in utero or in early life — is contributing to increased risk. The factors that at one point contributed to the rise in rates in non-Hispanic whites either are less common in that population or have already had whatever maximal effect they can have in that population," Dr. Schwartz said.

As far as lifestyle and environmental factors go, "it's all speculation at this point," he added.

In the period during which most patients with testicular cancer in this study were children, the height of Mexican American boys increased to a much greater extent than for white or black boys.

"Height, and more importantly, what height represents in terms of early life nutrition and its correlates, is my personal favorite. There is very strong evidence that it is associated with a higher risk of TGCT, and it fits well with the general theory that TGCT etiology has a strong early-life component," Dr. Schwartz explained.

Marijuana use has also been linked to testicular cancer risk in some recent research, and Hispanic Americans are currently more likely than white or black Americans to use marijuana.

But Dr. Schwartz does not think marijuana is driving the increased incidence of testicular cancer in Hispanic youth.

The same is probably true for environmental exposures, which could be a possible cause. These include heat, polyvinylchloride, nonionizing radiation, heavy metals, agricultural work, pesticides, and polychlorinated biphenyls. However, so far, there is no evidence to support links between these toxins and testicular cancer.

"These ideas that we touched upon in our paper are far more speculative; we included them mostly to be complete, rather than because they are good explanations. There are some good reasons why the marijuana and environmental toxin explanations are not as likely to be correct, at least based on currently available evidence," Dr. Schwartz said.

Dr. Schwartz has disclosed no relevant financial relationships.

Cancer. Published online July 14, 2014. Abstract


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