(Reuters Health) - Most men shouldn’t get routine prostate cancer screening because the potential benefits are small and there are clear harms, an international panel of experts concludes.

Some men, including those with a family history of prostate cancer, may have a greater chance of benefit from screening and should discuss the pros and cons with their physician to make an informed decision, medical experts recommend in guidelines published in the BMJ.

“Most, but not all, well-informed men that fully understand the trade-offs would choose not to undergo screening,” said co-author of the guidelines Dr. Philipp Dahm of the University of Minnesota and the Minneapolis Veterans Administration Medical Center.

“Only those men who place more value in even a small reduction of prostate cancer mortality - these may be men at higher risk because of a family history or because of African descent, or those simply very concerned about ruling out a cancer diagnosis - may opt for screening,” Dahm said by email. “Shared decision-making is needed to help them arrive at a decision consistent with their own values and preferences.”

Most men with prostate cancer are diagnosed with low-risk tumors that haven’t spread to other parts of the body. Often, doctors and patients struggle to choose between active surveillance and treatments like surgery or radiation, because it’s hard to tell which tumors will grow fast enough to be life-threatening and which ones might never get big enough to cause problems.

The prostate specific antigen (PSA) blood test is the only widely available test to screen for prostate cancer. It is used in many countries, but it remains controversial because it has increased the number of healthy men diagnosed with and treated unnecessarily for harmless tumors, the guidelines note.

In drafting the guidelines, experts reviewed research results from studies involving a total of more than 700,000 men. The studies showed that if screening reduces prostate cancer deaths at all, the effect is very small.

“PSA screening increases the number of men who need further diagnostic tests, such as prostate biopsy (approximately 100 per 1000 men screened), and it increases number of men diagnosed with prostate cancer (18 per 1000 men screened),” said lead author of the guidelines Dr. Kari Tikkinen of Helsinki University Hospital and University of Helsinki in Finland.

“However, many of these men would not have ever experienced any symptoms of the prostate cancer if not diagnosed,” Tikkinen said by email.

Because of this, it’s reasonable for doctors to only bring up the possibility of screening with men who have an increased risk, the guidelines conclude. For most men, who don’t have an increased risk, it’s fine for doctors to skip this conversation altogether.

“Prostate cancer is extremely common in men in their 70s and older and most of these men will die `with their cancer’ rather than developing complications and dying of it, and small prostate cancers do not cause any symptoms,” said Dr. David Neal, co-author of an accompanying editorial and a professor at the University of Oxford in the U.K.

“Therefore, if you have a screening program which diagnoses many of these men with rather slow growing cancers then you make a `well person’ into a patient,” Neal said by email. “Then some of these men will also be offered radical treatments with radiotherapy and surgery and develop the complications of treatment, but because their tumors were low risk they get no benefit from radical treatments because they never needed it.”

Because most physicians already think this way about screening, the new guidelines are unlikely to change clinical practice, Neal added.

SOURCE: bit.ly/2QUA8p7 BMJ, online September 5, 2018.