Prostate cancer: when to start being afraid?
An international team led by researchers from the University of California, San Diego School of Medicine has developed and approved a genetic tool for predicting the age at which an aggressive form of prostate cancer will develop.
The new scale can be used to identify population categories for cancer screening.
Currently, the main method of prostate cancer screening is to determine the level of PSA (prostate-specific antigen) in the blood. But, unfortunately, it does not have the desired accuracy: false positive results are frequent, that is, the PSA level is elevated, although there is no prostate cancer, or the tumor grows slowly and is not aggressive.
With all the effectiveness of screening by determining PSA, it is sometimes not enough. False positive results lead to an increase in the number of unnecessary interventions: prostate biopsy, surgery and even radiation therapy are performed by those to whom they are not shown.
Researchers from the USA, Europe and Australia used a genome-wide association search to determine the genetic predisposition to prostate cancer and predict the risk of aggressive course and death. A genome-wide search was performed for single-nucleotide polymorphisms, that is, differences between DNA in one nucleotide in the same sections of chromosomes present in people with certain diseases. In this study, about 200,000 such differences were estimated in 37,747 Caucasian men.
Using a method developed by researchers at the University of California, the group combined data from genome-wide association search and epidemiological studies to quantify the risk of prostate cancer at a certain age.
The polygenic risk scale specializes in the search for age-dependent genetic risks, it has already shown its effectiveness for predicting the age of onset of Alzheimer's disease.
In this study, the emphasis was placed on the age of development of aggressive prostate cancer. Genotype, presence or absence of prostate cancer and age were analyzed to determine single nucleotide polymorphisms associated with cancer. The data obtained were included in a polygenic risk scale, which also calculates the survival prognosis. This scale allows you to assess individual genetic risk. It was tested on an independent group of men participating in the ProtecT study currently underway in the UK.
The polygenic risk scale included about 54 single-nucleotide polymorphisms and proved to be a fairly effective predictor of the time of development of aggressive prostate cancer. Men who participated in the ProtecT study with high scores on the studied scale had a 2.9 times higher risk of aggressive prostate cancer compared to men with average scores.
In patients with diagnosed prostate cancer, the assessment according to the developed method was 4.6 times higher than the population average.
The researchers draw attention to the fact that the polygenic risk scale can be used at any age, since the human genotype remains unchanged throughout life. With its help, it is possible to identify men who need to conduct screening studies. This is especially important for those men who develop prostate cancer at an earlier age, before the time of the recommended screening. The authors write that determining the level of PSA in the blood gives more reliable data if it is carried out for men with high risk on a polygenic scale.
The application of a polygenic risk scale in practice is a step towards personalized medicine. Further studies are needed to evaluate its clinical advantages and disadvantages.
Article by Tyler M Seibert et al. The Polygenic hazard score to guide screening for aggressive prostate cancer: development and validation in large scale cohorts is published in the journal BMJ.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of the UC San Diego News Center: New Polygenic Hazard Score Predicts When Men Develop Prostate Cancer.