Benign prostatic hyperplasia has precise meaning

Editor—Kirby's editorial on benign prostatic hyperplasia presented a simplistic view of medical treatment for suspected benign prostatic obstruction.¹

Benign prostatic hyperplasia is a specific histological term often misused in general parlance. The importance of distinguishing between benign prostatic hyperplasia and benign prostatic enlargement and bladder outlet obstruction is fundamental. If men live long enough they will all develop histological benign prostatic hyperplasia, but only around half of them will develop benign prostatic enlargement; only around half of these will become obstructed and require treatment. It may suit those wishing to capture more patients in the treatment net to use terms imprecisely, but it is not beneficial for the medical community or patients as they may receive unnecessary treatment, with attendant morbidity and cost. My previous editorial in 1994 advocated the more precise use of terms²; indeed these terms have been taken up by the World Health Organization's sponsored consultation on the subject.³ Kirby's editorial refers to men with presumed prostatic obstruction due to benign prostatic enlargement, which is likely to be associated with histological benign prostatic hyperplasia.

Kirby's statement that the risk factors leading to acute retention can now be identified is an oversimplification. Severe lower urinary tract symptoms, reduced maximum urine flow rate, an enlarged prostate, and old age are associated only weakly with the occurrence of retention.⁴ Thus, which men will develop urinary retention cannot be predicted. The data quoted show that only a few patients develop retention over three years.

Two groups of drugs are active in reducing symptoms and partly relieving bladder outlet obstruction. 5α-Reductase inhibitors (including finasteride) have been investigated in long term studies because of their slow effect. α Adrenergic antagonists have not been investigated in long term placebo controlled studies, which in some countries would be regarded as unethical, largely because they work quickly. Hence whether α blockers prevent men from developing urinary retention is not known. Kirby did not mention that the degree of relief of symptoms and of obstruction is modest when compared with the results of conventional surgery such as transurethral resection of the prostate. Therefore in advising that men with big prostates should take finasteride to prevent complications, the advantages (a small reduction in acute retention (3% v 7% in the placebo group) and a modest improvement in symptoms) need to be weighed against the disadvantages (side effects such as impotence and the cost of prescriptions to patients and the state).

These issues were not discussed in the editorial, whose conclusions were misleading. Neither finasteride nor any other drug provides relief of symptoms in all but a few patients, and a reduction in long term complications is certainly unpredictable in individual men. Statistical associations are not necessarily clinically significant facts. The precise use of terms is crucial.