Recommended prostate-specific antigen testing intervals for the detection of curable prostate cancer.

Carter HB, Epstein LI, Chan DW, Fozard JD and Pearson JD.
Journal of the American Medical Association 1997, 277:1456-60.

This is an interesting study albeit complicated. The authors identified a cohort of patients with PSA values less than 2, between 2.1 and 4, between 4 and 5 and greater than 5 ng/ml. They showed that patients having normal digital rectal examination and serum PSA less than 2 were unlikely to develop higher PSA values that would place them in a category associated with non-curable prostate cancer within 2 or 4 years. Annual testing for these patients was therefore unnecessary. This would save large sums of money as about 70% of patients have PSA values less than 2 and so annual PSA tests would not be necessary. PSA conversion to a range at which cancers are likely to be curable (4.1-5.0 ng/mL) was common when the baseline PSA level was between 2.1 and 3.0 ng/mL (27%) or 3.1 and 4.0 ng/mL (36%). Such patients should have PSA tests more frequently.