Men who have high levels of prostate-specific antigen (PSA) in their blood face troubling uncertainties. While it’s true that prostate cancer can elevate PSA, so can other conditions, including the benign prostate enlargement that afflicts many men as they get older. PSA levels also vary normally from one man to the next, and some men have unusually high levels even when they’re perfectly healthy. To rule out cancer, doctors might recommend a biopsy. Yet prostate biopsies pose risks of infection, and they can also miss cancer in men who truly have the disease. Most prostate biopsies are guided by transrectal ultrasound, an imaging technology that allows doctors to see the gland while taking tissue samples (called cores) with specialized needles. Tumors may not show up on ultrasound, however, so the biopsy needles might never hit a cancerous target.
A more precise way to investigate elevated PSA results
In January, British researchers reported results from the multi-center PROMIS study showing that a different imaging technology, called multi-parametric magnetic resonance imaging (MP-MRI), could allow some men with high PSA levels to safely avoid a prostate biopsy altogether. “If my MP-MRI was negative, I would not have a biopsy,” said Mark Emberton, M.D., director of the Division of Surgery and Interventional Science at University College London, and a co-author on the study. “And I would do that confidently.”
An MRI machine uses a very large magnet, a radio-wave transmitter, and a computer to construct detailed pictures of structures inside the body. MP-MRI is an advanced form of the technology that allows specially trained radiologists to detect prostate tumors. They can also gauge how aggressive the tumor is by looking at how tightly the cells are packed and how blood and water molecules flow through them.
