I’m sure the nuances of A, B, C and D recommendations can be confusing to the public. They can also make it seem as if experts are constantly changing their minds. But this is how we want our experts to react: When new evidence is found, it should be added to older evidence to change our thinking when appropriate.

On the other hand, caution is still warranted when thinking about whether a man should be screened for prostate cancer. Although there is now evidence of a benefit, and its relative importance seems impressive, its absolute effects are not as persuasive.

According to these studies, a 55-year-old man has about a 0.6 percent chance of dying of prostate cancer over the next 10 to 15 years. If he is screened, that chance goes down to 0.5 percent. That’s how you get almost a 20 percent relative reduction, but an absolute reduction of only 0.1 percentage points.

Further, if a man is screened, the studies show that there’s about a 25 percent chance he will have a positive PSA test at some point. Of all men screened, about 10 percent will be found to have prostate cancer, and about 8 percent will be treated with surgery or radiation.

So out of 1,000 men screened, 80 will eventually have surgery or radiation. Three will avoid the spread of cancer to other organs. One or two will avoid death from prostate cancer. Sixty will have urinary incontinence and/or impotence. Many men will probably still think the risks outweigh the benefits.

One of the biggest concerns with screening is that too many men are treated for slow-moving prostate cancers that might never really pose a risk to their health. A new approach, known as active surveillance, offers an alternative. Instead of receiving immediate surgery or radiation, men with lower-risk cancer are watched more closely and receive more frequent PSA tests and biopsies. If the cancer progresses, they receive interventions. About 40 percent of men with lower-risk disease were treated this way from 2010 to 2013, up from 10 percent of men from 2005 to 2009.

The goal of health care, as always, should be to maximize the benefits of care while minimizing the harms. With this most recent recommendation, the preventive services task force recognizes that PSA screening now has more evidence to support its upside. There’s still a large downside, though, and the ways in which we respond to positive screens should try to minimize interventions.