19139

It would have been helpful to mention in this article that the free-PSA-ratio test is effective only for men with a prostate volume less than 40 cubic centimeters. The test doesn’t work for men with larger prostates. This is because, for larger prostates, the ratio of free to total PSA is elevated to roughly the same level in men with cancer and those with benign prostate hyperplasia but no cancer.

Robert Oglesby
Rochester Hills, Mich.

Researcher Peter H. Gann of Northwestern University Medical School in Chicago agrees that prostate volume should be taken into consideration by physicians diagnosing prostate ailments. He cautions, however, that no cutoff, such as 40 cubic centimeters, has been established as the point beyond which the free-PSA-ratio test doesn’t work. He also notes that prostate volume is difficult to ascertain .–N. Seppa