EVALUATION OF PROSTATIC INTRAEPITHELIAL NEOPLASIA AFTER TREATMENT WITH A 5-ALPHA-REDUCTASE INHIBITOR (FINASTERIDE) - A METHODOLOGIC APPROACH

OBJECTIVE: To develop a methodology applicable to the morphologic stud y of the efficacy of finasteride on prostatic intraepithelial neoplasi a (PIN), a putative precursor of prostate cancer. STUDY DESIGN: Three PIN foci were reviewed in two simple prostatectomy specimens from pati ents with clinical diagnoses of benign prostatic hyperplasia and treat ed with finasteride for six months. The feasibility of PIN diagnosis a nd golding based on ''diagnostic distance'' was investigated. It is a measure of the ''extent'' to which the observed features are different from those of the untreated prototypes representing the following dia gnostic categories: normal prostate, lo so and high grade PIN and pros tatic adenocarcinoma with a cribriform or large acinar pattern. Uncert ainty in the PIN diagnosis and grading was dealt with by means of a Ba yesian belief network (BBN). RESULTS: The distance measure values gf t he three PIN foci from the prototype of untreated, nonneoplastic prost ate were 9, 7 and 8, respectively, in relative, arbitrary units. Their distance from the two prostate cancer patterns (large acinar and crib riform) tons as high as 8-10. The distances of these foci from either low or high grade PIN were as low as 5, 3 and 2, and 3, 5 and 4, respe ctively. BBN produced the highest belief values for PIN, thus confirmi ng the morphology-based and diagnostic distance-supported diagnosis; h owever, the belief values were low for both grades. CONCLUSION: The re sults provided by BBN analyses and diagnostic distance measures suppor t the conclusion that this methodology is applicable to assessing the efficacy of finasteride treatment of PIN.