Familial prostate cancer risk influenced by screening awareness
MedWire News: Men with first-degree relatives who have prostate cancer are more likely to undergo prostate-specific antigen (PSA) screening than those with no family history, report researchers who believe that the finding may bias the results of genetic studies investigating familial prostate cancer risk.
Compared with the general population, men who have one or more brothers with prostate cancer have increased diagnostic activity, especially those of a high economic status, and particularly during the first year after the initial sibling is diagnosed, say the researchers.
Ola Bratt (Helsingborg Hospital, Sweden) and colleagues suggest that, "when counseling men about their risk for hereditary predisposition to prostate cancer, one should consider the possibility that a familial aggregation of prostate cancer may be at least partially caused by increased diagnostic activity."
The researchers investigated the effect of increased diagnostic activity among men with a family history of prostate cancer on their risk for the disease, using data for 13,975 prostate cancer patients and their 22,511 unaffected brothers from the Prostate Cancer Database Sweden.
The overall incidence of prostate cancer among the brothers of index patients (for whom one or more brothers and their father could be identified by national registries) was 3.1 times higher than men of the same age in the general Swedish population, write Bratt et al in the Journal of the National Cancer Institute.
The risk for stage T1c cancer was far higher among brothers of index patients (standard incidence ratio [SIR]=3.4) compared with the risk for metastatic disease, (SIR=2.0).
Additionally, among brothers of index prostate cancer patients, the incidence of prostate cancer was much higher during the first year after the index patient's diagnosis than during later years, at SIR 3.6 versus 2.5 and 2.8 at 5 years or more and 1-3 years, respectively.
Higher socioeconomic status (defined according to employment status) of the index patient was also associated with a higher risk for a prostate cancer diagnosis, and a diagnosis of low-risk disease among their brothers.
Brothers of high socioeconomic status patients had an SIR of 4.2 for T1c tumors compared with an SIR of 2.8 for brothers of low socioeconomic status patients.
In an accompanying editorial, Ian Thompson (University of Texas, Austin, USA) and colleagues comment: "Perhaps the best tactic would be to change our approach from seeking risk factors for prostate cancer to an assessment of factors related to biologically consequential prostate cancer."
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By Sarah Guy