MILWAUKEE – A rapid rise in the level of PSA in a man’s blood during the year before he’s diagnosed with prostate cancer is a likely sign that he’s at greater risk of dying of the disease and means more than the PSA score itself, a new study reports.

It suggests that delaying treatment and just monitoring the situation may be dangerous for such men.

It also may give a way to identify men who aren’t likely to be cured by having their prostates removed. Hormones or other treatments instead of or in addition to surgery may be better options for them. In the study, up to 28 percent of men with rapidly rising PSA scores died of prostate cancer despite having their prostates taken out.

The study was reported in Thursday’s New England Journal of Medicine. It was led by William Catalona, director of prostate cancer screening at Northwestern University, and was done when he held a similar job at Barnes-Jewish Hospital in St. Louis.

About 230,000 men in the United States are diagnosed with prostate cancer each year, mostly because of a high or rising level of PSA, which stands for prostate specific antigen, a substance the prostate makes when it’s inflamed.

The test is controversial because PSA can be high for many reasons besides cancer, and there’s no proof that PSA screening saves lives.

Prostate cancer is very common in older men and usually grows so slowly that most men with it die of something else.

But it kills about 29,000 Americans each year, and there’s no good way now to predict its aggressiveness.

Surgery creates problems for many men, such as having sex or controlling their bladders, so many try “watchful waiting” to monitor the situation instead of rushing to have their prostates taken out.

The new study shows the risk in that choice.

It involved about 1,100 men with cancer confined in or near the prostate, a gland at the base of the penis that makes seminal fluid. All had surgery to remove their prostates.

Seven years later, those whose PSAs had risen more than 2 nanograms per milliliter of blood during the year before their diagnosis died sooner and at higher rates than those whose PSAs rose less steeply.

Men with rapidly rising PSAs also were more likely to have tumors that were at more advanced stages. Five percent of them had cancer that had spread to their lymph nodes versus only 0.7 percent of the others.

“For these men, who are otherwise in good health, watchful waiting may not be the best option,” the researchers conclude.

Robert Donnell, associate professor at the Medical College of Wisconsin and co-director of the prostate center at Froedtert Memorial Lutheran Hospital in Wauwatosa, agreed.

“PSA is a better indicator of what has happened than what will happen,” Donnell said. “We can’t predict whose PSA will rise 2 nanograms per milliliter per year, so watchful waiting becomes a gamble.”

In an editorial in the medical journal, Mario Eisenberger and Alan Partin, prostate cancer experts from Johns Hopkins University, write that measures of PSA dynamics “may eventually be the key factor” in determining which men can safely try watchful waiting.

Other studies have found value in analyzing change in a man’s PSA rather than establishing a cutoff point such as 2.5 or 4 as cause for concern, they write.

Such research is forming a growing body of evidence that may help fine-tune interpretation of the PSA test and make it a more useful tool for detecting prostate cancer and evaluating its seriousness, experts say.

“This study shows us that no single value of PSA is as important as the trend,” Catalona said in a statement.