– Like any plumber, James Lyles, 73, wanted to know what was going on beneath the surface. Two years ago, his primary-care physician asked him whether he wanted to take a PSA test — a blood test for a “prostate-specific antigen” that helps physicians diagnose prostate cancer in its early stages.

Lyles agreed — and the test showed he did have cancer. Now, in the middle of radiation treatments, he said he is feeling OK. In his view, a $25 blood test helped keep him alive. “It only takes a vial of blood to tell you whether your health is in jeopardy or not,” he said. “It’s one of the easiest ways of finding out the truth about your body.”

Unintentionally, Lyles, who is black, had taken a side in a debate over prostate screening. A federal agency — the U.S. Preventive Services Task Force — said PSA tests for all men were unnecessary in 2012 before changing its mind last year and, in May, saying patients and their doctors should decide on screening on a case-by-case basis.

Black men are more likely than white men to develop and die of prostate cancer, and there is an ongoing debate about when tests should be given to them.

For urologist Navin Shah and Vladimir Ioffe, a radiation oncologist, conversations may not be enough when it comes to PSA screening. They recommend that every black man older than 50 be screened. “I think we are not doing justice to African-Americans if we do not screen them,” Shah said. “It is a very sad story.”

Shah and Ioffe have data to support screening in a paper published in Urology Times. Looking at tissue from nearly 2,900 biopsies, they found that after the Task Force said routine PSA screening was unnecessary in 2012, fewer biopsies were performed. But more of those biopsies revealed cancer, suggesting that some cases are being diagnosed later than they could have been.

“Despite a reduction in the total number of prostate biopsies by 30 percent, there was a 100 percent increase in the total number of positive prostate biopsies,” the study said. “The main point of this whole thing is trying to advocate for high-risk men,” Ioffe said. “They need to be screened.”

Discussing the need for PSA tests can set physicians against epidemiologists. On one hand, prostate cancer doesn’t always kill. Testing every man could lead to a lot of unnecessary treatment — including invasive ones such as prostatectomy that can lead to side effects like incontinence or erectile dysfunction. According to this interpretation, Shah and Ioffe’s findings is a good sign that healthy men aren’t getting unnecessary tests.

According to the National Institutes of Health, black men have a 15 percent chance of getting prostate cancer compared with 10 percent of white men. Their chances of dying are also higher — 4 percent among black men compared with 2 percent among white men.

Last month, researchers at the University of California at San Francisco studying 10,000 black prostate cancer patients found even those considered low-risk were twice as likely to die as patients from other demographics.

Daniel J. George, an oncologist at Duke University, said worries about overtreatment were understandable. But he said the paper showed such concerns were “not a reason not to screen.” “We may be diagnosing patients later in their disease course,” he said.

Shah, meanwhile, said the task force recommendations weren’t enough. Everybody has a right to know their diagnosis, he said.

“Black people are suffering,” he said. “That’s a fact.”