Researchers Find Race Has Role in Incidence, Survival of Rare Brain Tumor
The incidence of a rare and deadly tumor called primary central nervous system lymphoma (PCNSL) is two times higher in black Americans, ages 20 to 49, than in white Americans, according to a Mayo Clinic study published in the June issue of Journal of Neuro-Oncology. In patients older than 49, the results were reversed. White Americans were twice as likely as black Americans to be diagnosed with PCNSL.
Primary central nervous system lymphoma is a primary tumor of the central nervous system that may simultaneously or sequentially involve the brain, spinal cord, meninges (the covering of the brain and spinal cord) and the eyes. It most often affects the elderly, people who are immunosuppressed because of illness or transplant, and patients with AIDS. Though uncommon, this tumor is increasing in incidence, even in patients without known risk factors. About 1,500 new cases are diagnosed in the United States every year.
We undertook this epidemiological study to look for clues about the cause of PCNSL, says Brian O'Neill, M.D., a Mayo Clinic neurologist and the senior researcher in the study. Dr. ONeill is the director of Mayo's National Cancer Institute-designated Specialized Program of Research Excellence (SPORE) in Brain Cancer.
This study was conducted by reviewing the records of 2,665 patients between 1992 and 2002 in 13 U.S. communities that are part of the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute. This program is a repository for population-based information on cancer incidence and survival, covering 26 percent of the population and balanced for geographic, race and age differences. It has been used for etiologic cancer research for more than 30 years. In the study, researchers found the PCNSL incidence rates for adults ages 20 to 49 (all reported with a 95 percent confidence interval) were:
•Black Americans: 1.43 per 100,000 per year
•White Americans: 0.72 per 100,000 per year
Incidence rates for those older than 50 were:
•Black Americans: 0.56 per 100,000 per year
•White Americans: 1.30 per 100,000 per year
The number of American Indians, Alaska Natives and Asian/Pacific Islanders diagnosed with PCNSL was too low to draw any conclusions about disease incidence.