In early 2009, data from a Dutch study of 5,176 European men identified four factors to be helpful in predicting a man’s risk of developing prostate cancer:
- His serum prostate-specific antigen (PSA) level
- A prior negative biopsy of the prostate
- A family history of prostate cancer and
- His prostate volume
The men enrolled in this study were all aged between 55 and 75 years of age at the start of the study.
The results of the study were as follows:
- The average risk of developing biopsy-detectable prostate cancer over 4 years was 5.1 percent at an average PSA level of 1.5 ng/ml.
- Men with a serum PSA level > 1.5 ng/ml are at an above-average risk of developing prostate cancer over 4 years, and are at a sevenfold greater risk than are those with levels < 0.5 ng/ml.
- The risk for prostate cancer increases if there is a positive family history of prostate cancer, but decreases with an increasing prostate volume at the same PSA level.
- Risk also decreases if a man ever had a negative prostate biopsy.
In discussing the data from this study at a media conference at the time of release of the data, Roobol (the lead investigator for the study) gave a number of helpful examples of how to interpret the study’s results:
- First, a man with a high serum PSA, a positive family history, a small prostate, and no previous negative biopsy is at a higher than average risk, whereas a man with a low serum PSA and no additional risk factors is at a very low risk, which would be increased if he had a positive family history.
- Second, a man with a high PSA, no previous negative biopsy, and a small prostate (a prostate with a volume < 40 cm3) is at a higher than average risk, which would decrease if he had a larger prostate.
- Thus, a man with a PSA of 1.3 ng/ml, with no previous negative biopsy, a positive family history, and a prostate volume < 40 cm3, has a 5 percent risk of developing prostate cancer within 4 years.
- But a man with a previous negative biopsy, no family history, and a prostate volume > 40 cm3, can have a PSA up to 4 ng/ml, before reaching the similar threshold of a 5 percent risk of prostate cancer within 4 years.
These individualized predictive factors may be useful for the identification of men who are at higher than average risk thresholds and who may therefore be appropriate for more frequent screening and vice versa.
We would note that while risk assessment tools like the PCPT risk calculator and the Sunnybrook risk calculator (originally developed based on US and Canadian patients, respectively) may be used to assess risk in patients from other countries, the accuracy of those calculators in other populations has not been widely evaluated to date.