THURSDAY, July 19, 2007 (HealthDay News) -- The incidence of a rare cancer called cutaneous T-cell lymphoma has increased threefold over the past 30 years in the United States, a new study found.
Moreover, rates of the cancer vary by race, sex and geographic area, according to the report by researchers at the Veterans Administration Medical Center, Rhode Island Hospital and Brown University.
"Over 30 years, the incidence more than tripled," said lead author Vincent D. Criscione.
The reasons for this dramatic increase in the rates of cutaneous T-cell lymphoma aren't known, Criscione said. "One reason might be the increase in the efficiency of detection," he said. "The incidence was correlated with socioeconomic factors. Those with more education and higher income were more likely to have the condition."
In cutaneous T-cell lymphoma, cells of the lymph system called T lymphocytes become cancerous, affecting the skin. The term covers several types of lymphoma.
In the study, researchers Criscione and Dr. Martin A. Weinstock analyzed data from 13 cancer registries in the Surveillance, Epidemiology, and End Results Program of the U.S. National Cancer Institute. They collected data from 1973 through 2002.
During that period, they found 4,783 cases of cutaneous T-cell lymphoma; that represented 0.14 percent of all cancers and 3.9 percent of non-Hodgkin's lymphomas.
Criscione and Weinstock discovered that the number of these cancers increased each decade. In addition, there were more cases among blacks than whites and among men than women. The cases of cutaneous T-cell lymphoma also increased substantially with age.
San Francisco had the highest rates with 9.7 cases per million white patients and 10.8 cases per million black patients. Iowa had the fewest, with 3.7 per million among whites and 5.8 per million among blacks, the researchers found.
It's not known why there were more cases among blacks and men, or geographical differences, Criscione said. "It's a mysterious cancer, he said.
Identifying risk factors could provide a stepping stone to learning why these differences exist and why the number of cases has been increasing, Criscione said.
The study was published in the July issue of Archives of Dermatology.
One expert thinks the findings could help stimulate the search for the causes of cutaneous T-cell lymphoma and lead to new treatments.
"The incidence of cutaneous T-cell lymphoma is increasing, and we really don't know why," said Dr. Stuart R. Lessin, of Fox Chase Cancer Center in Philadelphia and author of an accompanying editorial in the journal.
"This [study] is an important piece of the puzzle in solving what may be causing this disease and developing better treatments," he said.
More information
For more on cutaneous T-cell lymphoma, visit the Leukemia & Lymphoma Society.
