Mar. 23 -- MONDAY, Aug. 13 (HealthDay News) -- Your prognosis for surviving prostate cancer may depend on your racial and ethnic background, a new study suggests.
Asian men have better survival rates than white males, while South Asians have the worst survival rates, according to results of a study of men living in California.
"Nearly all Asians do far better when they get prostate cancer," said study lead author Dr. Anthony Robbins, of the California Cancer Registry in Sacramento. "But Indian men didn't do as well as other Asian men, and they did worse than all other men, including blacks and whites," he added.
The reasons for these racial and ethnic differences in prostate cancer survival aren't known, Robbins said, adding, "We just couldn't explain it."
Not only couldn't the researchers explain the finding, they were left with an apparent paradox. The Asian men were usually older and had more advanced disease at the time of diagnosis, Robbins said. "Based on their risk factors, you would think they were going to do worse," he said.
In the study, Robbins and his colleagues collected data on 116,916 men (108,076 whites and 8,840 Asians from the six largest represented Asian ethnicities -- Chinese, Filipino, Japanese, Korean, South Asian, and Vietnamese) diagnosed with prostate cancer. The researchers compared prognostic factors and survival rates among the men.
The researchers found that for Asians, risk profiles were worse compared with whites. For example, Asians were more likely to have more advanced disease and use non-curative therapies. But, for Asians -- except for South Asians -- survival rates were equal to or better than rates for whites.
Japanese-American men were 34 percent less likely to die from prostate cancer compared with whites. But South Asian men -- those from India, Pakistan,Bangladesh, Sri Lanka, Nepal, and Bhutan -- were 40 percent more likely to die from the disease, Robbins said.
The study was published online Monday in the journal Cancer.
Some of the factors that may influence the findings include diet, exercise and genetics, Robbins speculated.
"Doctors that are seeing patients for prostate cancer need to be aware that these differences can be used as factors in planning the patient's treatment and telling the patient what their survival might be," Robbins said.
Dr. Durado Brooks, director of prostate and colorectal cancer at the American Cancer Society, thinks this study demonstrates the need to better understand how different racial and ethnic groups respond to diseases.
"This study points out the potential misleading conclusions we can come to when we use these large groups to lump different subpopulations into," he said.
"If you lump in the South Asian subgroup with other Asians, as is traditionally done, you totally miss the fact that these folks have a strikingly higher chance of dying from prostate cancer," Brooks said.
Brooks said the study finding can provide a basis for research to try to understand why these differences exist between populations.
Prostate cancer is the most common type of cancer to strike American men, other than skin cancer, according to the American Cancer Society, which estimates there will be about 218,890 new cases of prostate cancer in the United States in 2007, and about 27,050 men will die of the disease. Prostate cancer is the second leading cause of cancer death in males. While one in six men will get prostate cancer during his lifetime, only one man in 34 will die of the disease. The death rate for prostate cancer is declining, due in large part to earlier diagnoses, the society said.
Another paper in the same issue of the journal also found racial differences among women who survive breast cancer; with black women having poorer survival regardless of the stage of the disease.
It is known that black women had larger tumors and are more likely to have invasive breast cancer. But the study, lead by Dr. Alfred Neugut from Columbia University Medical Center and Russell McBride from Mailman School of Public Health, found that mortality among black women was up to 56 percent higher than whites.
Neugut's team says that the disparities in survival were surprising and suggest that non-clinical factors, such as access to and quality of care, may play a part.
For more on prostate cancer, visit the American Cancer Society.
SOURCES: Anthony Robbins, M.D., Ph.D., California Cancer Registry, Sacramento; Durado Brooks, M.D., director, prostate and colorectal cancer, American Cancer Society, Atlanta; Aug. 13, 2007, Cancer, online