The number of cancer survivors in the United States has more than tripled, to almost 10 million, over the past three decades because of advances in detection and treatment, the government said Thursday.

Also, patients whose cancer was diagnosed between 1995 and 2000 have an estimated 64 percent chance of surviving five years, compared with a 50 percent rate three decades ago, a study by National Cancer Institute and the Centers for Disease Control and Prevention found.

"Cancer is not necessarily a death sentence as often was seen in the past -- and still is," said Loria Pollack, CDC medical officer.

The number of cancer survivors -- defined as anyone in whom cancer has been diagnosed, no matter how recently -- soared from 3 million in 1971 to 9.8 million in 2001, the study found.

That number is likely to continue increasing as the population ages, because cancer risks increase with age, said Julia Rowland, director of the NCI's Office of Cancer Survivorship.

The government wants to increase the overall five-year survival rate to 70 percent by 2010.

Medical advances have also helped children with cancer live much longer, the study said. In the 1970s, the five-year survival rate was about 50 percent. Now it is 80 percent, Pollack said.

The study said health officials need to do more for the long-term care of cancer survivors.