Photo by Todd McNaught
A man's race and ethnicity may significantly affect his chances of surviving testis cancer, according to a recent Public Health Sciences Division study.
In an analysis of data on more than 16,000 U.S. men with the disease, researchers found that compared to non-Hispanic whites, testis-cancer patients who were African-American, Native American, Filipino or Hawaiian were more than twice as likely to die of their cancer. Survival rates also were poorer for Hispanics. Consistent with these findings, many patients of racial and ethnic minority backgrounds were more likely to have their disease diagnosed at late stages, when it is more difficult to cure.
The results appear in the June issue of Cancer Causes and Control.
The new findings — based on the largest and most comprehensive analysis of its kind — contribute to a growing body of evidence that cancer takes a harder toll on racial and ethnic minorities in the United States than on non-Hispanic whites.
The underlying reasons for these differences, which may stem from socioeconomic or biological factors or both, have not yet been analyzed for testis cancer. But the new data provide the groundwork for future research that could improve outcomes for all patients, said Mary Lou Biggs, who led the study along with Dr. Stephen Schwartz.
"The first important step is to figure out why many nonwhite men are diagnosed when their cancer is at an advanced stage," said Biggs, a graduate student in the University of Washington Department of Epidemiology who is completing her doctoral research with Schwartz. "A major factor in lower survival probabilities is that the disease isn't being caught and treated early, when response to treatment is excellent. However, stage is just one factor because when we compared men diagnosed at the same stage, survival among African-Americans, Native Americans, Hawaiians, Filipinos and Hispanics was still poorer than among non-Hispanic whites."
Effective chemotherapy for testis cancer has boosted overall survival rates from 72 percent in the early 1970s to 96 percent for men diagnosed between 1992 and 1999. The disease is considered one of the most curable forms of cancer. Although testis cancer is relatively rare — there are expected to be about 8,900 cases in the United States this year — it is the most common cancer in men aged 20 to 34.
"The improvement in survival rates for testis cancer is one of the brightest spots in war on cancer," Biggs said. "We'd like to see that success being shared by all men with the disease."
To explore whether race and ethnicity affect testis-cancer survival, the researchers obtained data from the National Cancer Institute's Surveillance, Epidemiology and End Results (SEER) program, a network of cancer registries around the nation. The registries maintain databases on cancer incidence, outcome and tumor pathology as well as demographic information including age, race/ethnicity, gender and other characteristics. The PHS Division houses the registry for western Washington, which is called the Cancer Surveillance System.
16,000 cancer patients
Records were analyzed for 16,086 men who were diagnosed with testis cancer between 1973 and 1999. Cancer cases were categorized according their stage at diagnosis, which describes whether the cancer is limited to the testis or has spread regionally or to distant parts of the body.
Native Americans and Hawaiians had the highest proportion (27 percent) of patients diagnosed with distant testis cancer, followed by African-Americans and Hispanics (16 percent). The proportion of distant cancers among non-Hispanic whites (12 percent) was similar to that of Filipinos, Chinese and Japanese.
Overall, survival from testis cancer was good, with only 886 deaths out of 16,086 cancer cases from the disease occurring over a 27-year period. However, compared to non-Hispanic white patients, African-Americans, Native Americans, Filipinos and Hawaiians were about two to three and one-half times more likely to die from the disease. Hispanic men with testis cancer were about 40 percent more likely to die from the cancer than non-Hispanic whites.
"These differences are not unlike what has been observed in other studies that have examined the effects of race and ethnicity on outcomes for other types of cancer," Biggs said. She said that further work is required to determine whether the disparities reflect true biological differences or differences for which race is a surrogate marker, such as socioeconomic status, access to health coverage, and environmental and cultural factors.