ROCHESTER, Minn., July 31 (UPI) -- A rare tumor called primary central nervous system lymphoma was two times more likely to be found in blacks ages 20 to 49 than whites, U.S. researchers said.
In patients older than 49, however, the results were reversed with white people twice as likely to have the deadly tumor, researchers at the Mayo Clinic, Rochester, Minn., said in a release Friday.
The tumor most often affects people with damaged immune systems, the researchers said in the journal of Neuro-Oncology.
The tumor is increasing in incidence, even in patients without known risk factors, with an estimated 1,500 new cases being diagnosed in the United States every year, Dr. Brian O'Neill, the study's lead author, said.
O'Neill and his team discovered the tumor's link to race while reviewing the records of 2,665 patients between 1992 and 2002 in 13 U.S. communities.
It's yet to be discovered whether the tumor is caused by genetics, environment or a combination of both, O'Neill said.