Increasing death rates from prostate cancer have federal health officials questioning the benefits of expensive tests to detect the disease earlier.

The Centers for Disease Control reported Thursday that deaths from prostate cancer increased 7.5 percent among white men and 5.9 percent among black men from 1980 to 1988, the latest year figures were available.The rise came despite greater use of newer, more sophisticated and expensive tests - such as ultrasound and an antigen blood test - aimed at detecting cancers earlier when treatment may be more effective.

"There is clearly something going on. It's becoming a growing public health problem," said Ron Aubert, a CDC epidemiologist. "But there are studies that are needed to evaluate the benefit of screening and early detection.

"We're not to the point that organizations feel comfortable making recommendations that people get these early screenings, as they have with breast and cervical cancer."

The Atlanta-based CDC reported that in 1980, about 17.3 white men per 100,000 - or a total of 19,095 - died from prostate cancer. The rate reached 18.6 in 1988, when the total was 24,175.

For blacks, the rate was 37.4 deaths per 100,000 in 1980 - a total of 3,670 - and 39.6 in 1988 - a total of 4,581.

The American Cancer Society predicts 34,000 deaths in the United States this year from prostate cancer, which generally strikes men over age 50.

The prostate is a gland surrounding the urethra at the base of the male's bladder. Doctors generally check for tumors during a rectal examination.

Some men opt for more expensive tests. The prostate specific antigen test, which costs about $75, screens blood samples for elevated levels of an antigen associated with the prostate. Critics warn that the levels can increase for reasons other than tumors.

Also available is ultrasound, in which sound waves can detect small tumors.

"Despite the improved effectiveness of (all three tests) to detect disease at earlier stages, these methods have not yet been associated with a reduction in prostate cancer mortality," the CDC report said.