Description: THURSDAY, July 19 (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, resea