Editorial comment

Abstract

The question that this article begs is, why a practicing urologist should care whether a laboratory test can predict the actual prostate volume in a patient with lower urinary tract symptoms associated with BPH. The answer is complex. Several years ago, it was shown that a clinically useful correlation exists between the total serum PSA level and total prostate volume as measured by TRUS in men in whom prostate cancer had been excluded by routine clinical care (ie, performing a biopsy in those men with an elevated PSA level). 1 Roehrborn C.G Boyle P Gould A.L et al. Serum prostate specific antigen (PSA) is a reliable surrogate for prostate volume. Urology. 1999; 53: 581-590 Abstract Full Text Full Text PDF PubMed Scopus (280) Google Scholar These findings have been verified by others subsequent to the original publication. This observation in itself, although intellectually interesting, is of limited clinical utility. However, baseline parameters that predict the natural history of a given disease are clinically useful. To this end, it has been shown that total serum PSA is the best baseline predictor of episodes of acute urinary retention, as well as the need for prostate-related surgery in men with BPH. 2 Roehrborn C.G McConnell J.D Lieber M.M et al. Serum prostate specific antigen concentration is a powerful predictor of acute urinary retention and need for surgery in men with clinical benign prostatic hyperplasia. Urology. 1999; 53: 473-480 Abstract Full Text Full Text PDF PubMed Scopus (265) Google Scholar , 3 Roehrborn C, Malice M-P, Cook T, et al: Clinical predictors of spontaneous acute urinary retention in men with LUTS and clinical BPH: a comprehensive analysis of the pooled placebo groups of several large clinical trials. Urology 58: 210–216, 2001 Google Scholar Furthermore, it had been shown that serum PSA is also the best predictor of future prostate growth. 4 Roehrborn C.G McConnell J Bonilla J et al. Serum prostate specific antigen is a strong predictor of future prostate growth in men with benign prostatic hyperplasia PROSCAR long-term efficacy and safety study. J Urol. 2000; 163: 13-20 Abstract Full Text Full Text PDF PubMed Scopus (200) Google Scholar Finally, it predicts whether patients will have symptomatic worsening and deterioration of urodynamic parameters. 5 Roehrborn CG, McConnell JD, Bonilla J, et al: Serum prostate specific antigen and prostate volume predict long-term changes in symptom and flow rate: results of a four-year randomized trial comparing finasteride versus placebo. Urology 54: 662–669, 1999 Google Scholar Of course, serum PSA is not perfect in predicting these events, and many patients with a low PSA level will develop problems, and other patients with a high PSA level will not. The present article examined BPSA, a subform of PSA, and its relationship to age and physiologic measures in lower urinary tract symptoms and BPH. Although BPSA was found to have a slightly better performance characteristic in terms of its correlation to the total and TZ volume, the most significant finding, perhaps, was that, unlike total PSA, BPSA has an age-independent relationship to the TZ volume of the prostate (ie, the amount of tissue actually representing BPH). Thus, at present, BPSA is the best predictor of clinically significant enlargement of the TZ of the prostate, which is to say, the best predictor of what we currently understand BPH to be. In addition, there is at least a modest correlation between BPSA and certain aspects of the subjective symptom spectrum associated with the disease. What is not shown in this article but is of crucial importance is the question of whether BPSA is superior to total PSA in predicting the natural history of the disease. Clearly, if BPSA or other molecules in a more precise manner were able to predict symptom progression, deterioration of flow rate, future prostate growth, and subsequent episodes of retention and/or surgery, it would be a most welcome addition to our diagnostic armamentarium. In fact, the more precise the instrument is, the more useful it is to clinicians and the more cost-effectively clinicians can practice preventive medicine with the use of 5-alpha-reductase inhibitors to prevent that progression. If one could demonstrate that BPSA predicts with reasonable accuracy significant progression, the use of 5-alpha-reductase inhibitors in a preventive setting would be a very reasonable preventative strategy. Future studies to evaluate this are certainly needed and likely will be carried out on existing databases and in future studies.