Why PSA Measurements Are Used
In general, PSA increases with age as a result of a gradually enlarging prostate. This has prompted the suggestion that the upper limit of a normal PSA should gradually increase with increasing age. Traditionally, the upper limit of normal is 4.0 for all men, but when adjusted for age, it is lower for younger men and higher for older (i.e., 2.5 for ages 40–49, 3.5 for ages 50–59, 4.5 for ages 60–69, and 6.5 for ages 70–79). This allows more cancers to be picked up in younger men, when they are potentially curable, and fewer cancers to be detected in older men, when treatment is more likely to be unnecessary. And it prevents some unnecessary biopsies in older men with borderline high PSA levels due to BPH. Some leading researchers have begun to study the range of PSA from 2.5 to 4.0 and have shown an increased risk, compared to less than 2.5 (about 22 out of 100 diagnosed with cancer when PSA is 2.6–4.0 versus 12–17 out of 100 when PSA is anything under 4.0, in men with a normal DRE).
In general, the use of age specific PSA ranges appears helpful, but more data needs to be collected to enable guidelines to be developed for its use. Until then, it has not been universally accepted for two reasons. First, some doctors feel that too many potentially lethal cancers may be missed in older men and, second, there is as much variation within an age group as there is between age groups.
