Purpose: The term atypical small acinar proliferation (ASAP) has been proposed by pathologists to indicate foci of small atypical acini found in prostatic biopsies that have some but not all of the features of adenocarcinoma. We determined the incidence of ASAP at our institution and evaluated the role of immediate radical prostatectomy (RP) in these patients.
Materials and methods: From January 2001 to December 2002, 1,327 patients underwent systematic transrectal prostate biopsies because of increased prostate specific antigen (PSA). Of the 1,327 patients 71 (5.3%) had suspicious cytokeratin negative lesions diagnosed as ASAP, as confirmed by a review pathologist. Mean patient age was 62 years and mean PSA was 8.48 ng/ml (range 5.6 to 19.6). Of the 71 patients 25 underwent pelvic bilateral lymphadenectomy and RP with a nerve sparing procedure immediately after the diagnosis of ASAP. A 79-year-old patient underwent transurethral resection of the prostate. A total of 45 patients were followed with PSA determination every 3 months and with prostatic mapping every 6 months (12 to 14 biopsies).
Results: All 25 patients (100%) with ASAP who underwent immediate RP had a final pathological diagnosis of adenocarcinoma, as confirmed by a review pathologist. Pathological stage was pT2a in 9 patients, pT2b in 8, pT2c in 6, pT3a in 1 and pT4 in 1. The Gleason sum was 2 to 6 in 21 patients, 7 in 2 and 8 in 2. One of the 25 patients had positive nodes (pT4N1G3). The pathological diagnosis in patients with transurethral resection was benign prostatic hyperplasia. Nine of the 45 patients who were followed were seen every 3 months for PSA determination because of age (older than 78 years). Of the 45 patients 23 (51.1%) underwent a second set of biopsies, which revealed adenocarcinoma in 6 of 23 (26%), benign prostatic hyperplasia in 6 (26%), ASAP again in 5 (21.7%), atypia in 4 (17.3%) and high grade PIN in 2 (8.6%). Six of 17 patients had a third set of biopsies (a total of 14 cores), including 3 with adenocarcinoma, 1 with ASAP and 2 with high grade PIN. Two of 45 patients (4.4%) did not undergo a second biopsy because of other malignancies. Four of 45 patients (8.8%) are awaiting a third or fourth biopsy. Ten of 45 patients (22.2%) were lost to followup.
Conclusions: The results of our study confirm that immediate RP could be the treatment of choice in young patients with ASAP.