Do patients with PSA levels less than 4 nd/dl need a biopsy?
We now know from the recent Prostate Cancer Prevention Trial (PCPT) that approximately 25% of men with a PSA in the range 2.1-4.0 ng/ml will be found to have prostate cancer.[10] Twenty one percent of these cancers are considered high grade supporting the fact that these are clinically significant tumors. Another study found that 14% of men with an abnormal DRE and a PSA 2.5-4.0 ng/ml had prostate cancer, supporting the idea that men with really low PSAs can still have cancer. Based on this information some urologists are justifying proceeding with prostate biopsy when the PSA is above 2.5 ng/ml. Another scenario in which a biopsy is warranted with a low PSA is in the patient taking a 5-alpha-reductase inhibitor (finasteride, dutasteride) for prostate enlargement. These medicines are well known for artificially lowering a man’s PSA by 50% after taking the medicine for 6 months. Therefore a man on one of these medicines with a PSA of 3.0 should really be considered as having a PSA of 6.
