A new study from Sweden suggests that the risk of prostate cancer in men with a known family history of the disease could be inflated because such men are more likely to seek a diagnosis, further intensifying the controversial debate on whether PSA testing does more harm than good.

Experts writing in the same journal propose that if you consider that many men in the population at large may have the disease but don’t take a test to find it, then cases of men who seek a diagnosis because a brother or father has tested positive, will exaggerate any familial link.

You can read a paper on the study and the accompanying editorial in the 19 August advanced online issue of Journal of the National Cancer Institute .

Dr Ola Bratt, from the Department of Urology at Helsingborg Hospital, and colleagues wrote in their background information that epidemiological and other studies suggest family history is a stronger risk for prostate cancer than many other cancers.

However, since the PSA (prostate-specific antigen) test came into use in the early 1990s, men whose fathers and brothers have been diagnosed with the disease have been the most likely group to take the test, so the researchers decided to investigate whether increased diagnostic activity is linked in any way to the incidence of prostate cancer among brothers of men with the disease.

For the study, they examined data on patients diagnosed with prostate cancer between 1996 to 2006 recorded in Sweden’s nationwide population-based Prostate Cancer Database (PCBaSe Sweden), which includes cases registered in the National Prostate Cancer Register and other sources.

First they looked for “index” patients: prostate cancer patients recorded in the National Prostate Cancer Register, for whom they could also identify at least one brother and their father from Sweden’s Multi-Generation Register, which includes family information for Swedish residents born since 1932.

Altogether they found data on 22,511 brothers of 13,975 index patients in the PCBaSe Sweden database.

They gathered a range of information on each index patient’s brother, such as type of tumor, time elapsed between their diagnosis and that of the index patient, calendar period, socioeconomic status and geographical situation and compared it to their incidence of prostate cancer.

The researchers found that: Brothers of index patients with prostate cancer were at increased risk for a diagnosis of prostate cancer than same-age men in the general Swedish population (standardized incidence ratio SIR = 3.1, 95% confidence interval CI ranged from 2.9 to 3.3).

The risk was even higher among brothers of index patients whose fathers also had prostate cancer.

The risk was highest among men with two brothers with prostate cancer.

However, the type of cancer most often detected was early stage, which is typically diagnosed via PSA test and may or may not become clinically relevant.

Rate of prostate cancer diagnosis among brothers of index patients was highest in the first year following the index patient’s diagnosis.

The rate was also highest among brothers with a higher socioeconomic status.