WASHINGTONCancer remains the second leading cause of death in the United States, but the disease's mortality rate declined by 2.9% in 2004, according to the Centers for Disease Control and Prevention (CDC). Total US cancer deaths in 2004 numbered 550,270. Preliminary mortality data put the age-adjusted death rate for malignant neoplasms at 184.6 per 100,000 population, down from 190.1 in 2003. The nation's overall death rate fell to a record low of 801 per 100,000 persons, down from 833 the previous year. The preliminary data are based on approximately 90% of the 2004 death records reported by the 50 states.