SACRAMENTO, Aug. 13 (UPI) -- Prognostic factors for prostate cancer survival do not explain why most Asian-American men have better survival compared to white men, says a U.S. study.

The study, published in the Sept. 15 journal Cancer, showed that compared to white men, most Asian ethnic groups except South Asians paradoxically have better outcomes despite having worse prognostic profiles at the time of diagnosis.

Dr. Anthony Robbins of the California Cancer Registry in Sacramento, Calif., and colleagues compared prognostic factors and survival rates of 116,916 men -- 108,076 whites and 8,840 Asians from the six largest represented Asian groups living in the United States of Chinese, Filipino, Japanese, Korean, South Asian, and Vietnamese -- diagnosed with prostate cancer.

The data show some Asian ethnicities, such as Japanese-Americans, have higher survival rates for prostate cancer despite worse clinical disease, Robbins found.