An important step forward in gauging men’s prostate cancer risk

It’s been more than a decade since new screening guidelines issued by the United States Preventive Services Task Force (USPSTF) advised against routine prostate-specific antigen (PSA) testing for prostate cancer.

At the time, it seemed like the logical thing to do. PSA screening isn’t 100 percent accurate and can lead to false-positive results. And that can result in unnecessary biopsy and treatment, not to mention a lot of anxiety.

However, this scaling back of PSA testing has accompanied a worrying rise in cases of metastatic prostate cancer. Between 2003 and 2017, patients diagnosed with prostate cancer that has spread to other parts of the body increased from 4 percent to 8 percent.

With the 5-year survival rate for metastatic prostate cancer at a dismal 31 percent, it’s extremely important to reverse that statistic. Testing is certainly one way to do this, since the 5-year survival rate for prostate cancer caught in the early stages is nearly 100 percent.

That’s why scientists in the United Kingdom have been exploring ways to identify men at greatest risk of developing prostate cancer — and it looks like they are on the right path…

Web tool predicts those at high risk

CanRisk is a free tool developed by the University of Cambridge and The Institute of Cancer Research, London. It’s used by healthcare professionals worldwide to help predict the risk of developing breast and ovarian cancers.

To date, it has recorded almost 1.2 million risk predictions. And now researchers have added prostate cancer to the CanRisk tool.

“What we need is a way of identifying those men who are at greatest risk, allowing us to target screening and diagnostic tests where they are most needed, while also reducing the harms for those men who have low risk of the disease,” says Antonis Antoniou, a professor at the University of Cambridge.

“This is what CanRisk-Prostate aims to do. For the first time, it combines information on the genetic makeup and prostate cancer family history, the main risk factors for the disease, to provide personalized cancer risks.”

It’s partly in the genes

The researchers developed the CanRisk-Prostate model using genetic and cancer family history data from almost 17,000 families affected by prostate cancer. It employs data on rare genetic faults in moderate to high-risk genes as well as a risk score based on 268 common low-risk variants. It then combines this data with a detailed cancer family history to predict future risk.

One in six men will develop prostate cancer by the time they are 85 years old. Using the model, researchers found predicted risk was higher for men who had a father diagnosed with prostate cancer. The risk ranged from 27 percent if the father was diagnosed at 80 years of age to 42 percent if the father was diagnosed at 50 years of age.

Genetic faults increased the risk considerably. For instance, 54 percent of men who carry an altered BRCA2 gene would go on to develop prostate cancer. However, among those men with BRCA2 gene faults, the risk was substantially lower if they also had a small number of the low-risk gene variants, with risk rising as the number of low-risk variants increased.

By using CanRisk-Prostate, clinicians will be able to use any combination of cancer family history, and rare and common genetic variants to obtain a personalized risk profile for patients.

The researchers ran the risk model on an independent cohort of men from the UK Biobank biomedical database and research resource. All of the more than 170,000 men were free from prostate cancer when recruited to the study, but more than 7,600 developed prostate cancer within the subsequent 10 years.

When validating the model, the team found 86 percent of the UK Biobank participants who developed prostate cancer were in the 50 percent of men with the highest predicted risks. This suggests the possibility of targeting screening and diagnostic tests to the population subgroup at highest risk — since the majority of prostate cancers will likely occur among them.

Eventually, CanRisk-Prostate will enable risk-adapted early detection approaches to the general population.

So far, the data used to develop CanRisk-Prosate is from men of European ancestry, but the researchers hope to include data from men of other ethnicities as further research is done.

What qualifies as high risk?

Lifestyle certainly plays a role in prostate cancer risk. Maintaining a healthy weight and eating a diet low in processed foods and added sugars are two ways you can help lower your risk of the disease.

However, there are three risk factors you need to be aware of that are beyond your control.

Age is one of the biggest risk factors for prostate cancer. Prostate tumors usually develop in men older than 50, with more than 6 in 10 cases occurring in men who are 65 and up. But the good news here is that multiple studies show exercise can shrink prostate tumors and extend survival and quality of life.

Another risk factor is having a family history of the disease. If your father, brother or another close blood relative had prostate cancer, it raises your risk of the disease, especially if they were diagnosed before the age of 60. Inherited genetic factors may be related to between 5 and 10 out of every 100 prostate cancers.

Finally, if you are African American, you’re more likely to develop prostate cancer, and it’s more likely to be advanced when you’re diagnosed.

If you have any of these three risk factors, you’ll want to talk to your doctor about whether (and how often) you should get screened for prostate cancer.

Sources:

Prostate cancer risk prediction algorithm could help target testing at men at greatest risk — University of Cambridge

CanRisk-Prostate: A Comprehensive, Externally Validated Risk Model for the Prediction of Future Prostate Cancer — Journal of Clinical Oncology

Metastatic prostate cancer on the rise since decrease in cancer screenings — Keck Medicine of USC

CDC warns incidence of metastatic prostate cancer on the rise — Urology Times

PSA screening in prostate cancer: The controversy continues — Urology Times

Prostate Cancer: Statistics — Cancer.Net

Prostate Cancer Causes & Risk Factors — Memorial Sloan Kettering Cancer Center