Incidental prostatic adenocarcinomas and putative premalignant lesions in TURP specimens collected before and after the introduction of prostrate-specific antigen screening.

BACKGROUND: Since the introduction of prostate-specific antigen (PSA) screening for the detection of prostatic adenocarcinoma (PCA), there has been an increase in the incidence of stage T1c PCA. The purpose of this study was to compare the frequency of incidental PCA found in transurethral resection of prostate (TURP) specimens for a 14-month period during 1989-1990 (before PSA screening was available) with the incidence of PCA for a 32-month period during 1997-1999 (after PSA screening became available). DESIGN: Consecutive TURP specimens from the 2 time periods were reviewed to identify incidental PCA, prostatic intraepithelial neoplasia (PIN), and atypical adenomatous hyperplasia (AAH). Cases of TURP for palliative treatment of known advanced PCA were excluded from the study. All TURP specimens were fixed in 10% buffered formalin and were processed according to the same protocol. RESULTS: We reviewed 533 and 449 TURP specimens for the time periods 1989-1990 and 1997-1999, respectively. Comparison of the results for these 2 time periods revealed that the combined prevalence of T1a and T1b PCA decreased over time from 12.9% to 8.0% (P =.06) with the introduction of PSA screening. A new group of T1c PCA was established in the post-PSA screening period of 1997-1999. There were no statistically significant differences in the incidences of T1a PCA, PIN, and AAH in TURP specimens for the 2 time periods. CONCLUSION: The decreased incidence of T1b PCA in TURP specimens for the 1997-1999 period represents a shift in PCA staging. Some PCAs previously staged as T1b are now staged as T2 carcinomas, as a result of PSA screening and earlier clinical detection. The introduction of PSA screening has had no influence on the incidence of T1a PCA, PIN, or AAH in TURP specimens.