With more than 333,000 new cases every year, prostate cancer is the most frequently diagnosed cancer in the U.S., and by far the most common among men. A good number of prostate cancer experts think these low-grade lesions “shouldn’t even be called a cancer,” said Scott Eggener, a professor of urology at the University of California, Los Angeles. The ubiquity of prostate cancer, he and these other experts argue, is an overdiagnosis problem. “I would say the vast majority [of urologists] don’t know how to read a prostate MRI … even nowadays, many residents don’t come out knowing how to read a prostate MRI reliably.” A negative prostate MRI is, he said, “just like … a normal mammogram, normal brain scan, normal lung scan.”