The federal Centers for Disease Control and Prevention (CDC) estimates that the U.S. spent $48.1 billion annually to treat cancer between 2001 and 2005, nearly double the cost of cancer care recorded in 1987.

HealthDay News reported May 10 that the CDC attributed the increase in part to a rising number of cancer patients seeking care; costs rose despite a shift from inpatient to outpatient care.

The latest data show that private insurers paid about half of the total cost of cancer care, with Medicare paying 34 percent. In 1987, private insurers paid 42 percent of cancer-treatment costs, while Medicare paid 33 percent.

The findings were published online in the journal Cancer.