WASHINGTON — Good news on the cancer front: Death rates are dropping faster than ever, thanks to new progress against colorectal cancer.

A turning point came in 2002, scientists conclude today in the annual “Report to the Nation” on cancer. Between 2002 and 2004, death rates dropped by an average of 2.1% a year.

That may not sound like much, but between 1993 and 2001, deaths rates dropped on average 1.1% a year.

The big change was a two-pronged gain against colorectal cancer.

While it remains the nation’s no. 2 cancer killer, deaths are dropping faster for colorectal cancer than for any other malignancy — by almost 5% a year among men and 4.5% among women.

One reason is that colorectal cancer is striking fewer people, the report found. New diagnoses are down roughly 2.5% percent a year for both men and women, thanks to screening tests that can spot precancerous polyps in time to remove them and thus prevent cancer from forming.

Still, only about half the people who need screening — everyone over age 50 — gets checked.

“If we’re seeing such great impact even at 50% percent screening rates, we think it could be much greater if we could get more of the population tested,” Dr. Elizabeth Ward of the American Cancer Society, who co-wrote the report, said.

The other gain is the result of new treatments, which are credited with doubling survival times for the most advanced patients.

In 1996, there was just one truly effective drug for colon cancer. Today, there are six more, giving patients a variety of chemotherapy cocktails to try to hold their tumors in check, a medical oncology chief at Philadelphia’s Fox Chase Cancer Center and a colorectal cancer specialist, Dr. Louis Weiner, said.

“I can tell you the offices of gastrointestinal oncologists around the country, and indeed around the world, are busier than ever because our patients are doing better,” he said.