Initial atypical diagnosis with carcinoma on subsequent prostate needle biopsy: findings at radical prostatectomy

Atypical small acinar proliferation and two or more cores of high-grade intraepithelial neoplasia on a previous prostate biopsy are significant predictors of cancer during a transperineal template-guided saturation biopsy aimed at sampling one core for each 1 mL of prostate volume

Objective

The objective of this study was to evaluate whether high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical small acinar proliferation (ASAP) predict prostate cancer (PCa) during repeat transperineal template saturation biopsy with a high number of cores per prostate volume in patients with persistent clinical suspicion of PCa who underwent at least one previous negative transrectal ultrasound (TRUS)-guided biopsy.

Methods

We retrospectively evaluated 135 consecutive patients with persistent clinical suspicion of PCa, despite a set of negative TRUS-guided biopsies and increasing prostate-specific antigen levels; abnormal findings on digital rectal examination, TRUS, or magnetic resonance imaging; previous biopsy showing HGPIN; and previous biopsy showing atypical glands. Transperineal template saturation biopsy (TTSB) was performed at 5mm intervals to sample one core for each 1 mL of prostate volume.

Results

The median rate of biopsy cores per prostate volume was 1.00 (range: 0.75–1.39). The PCa detection rates in patients who were diagnosed with HGPIN, or had two or more cores of HGPIN or ASAP, were 53% (9/17), 89% (8/9), and 83% (10/12), respectively. Two or more HGPIN cores and ASAP were positive predictors of PCa on TTSB. The high-grade cancer rates (Gleason score [GS] ≥7) in patients with ASAP and two or more cores of HGPIN were 20% and 80%, respectively. The cancer detection rate represented by a GS score ≥8 in patients with ASAP or two or more cores of HGPIN at a previous TRUS-guided biopsy was 5.5% (1/18).

Conclusion

ASAP or two or more cores of HGPIN at a previous TRUS-guided biopsy strongly indicated the presence of PCa on TTSB.

Managing high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical glands on prostate biopsy

Prostate biopsy is the gold standard for diagnosing prostate cancer and reliable pathological assessment is essential for guiding management. Research efforts over the past few years have aimed to establish a more universal approach to management according to pathological grading; however, high-grade prostatic intraepithelial neoplasia (HGPIN) and atypical glands suspicious for carcinoma are two diagnoses without standardized follow-up and treatment pathways. Much of this uncertainty is due to limited evidence describing the subsequent rates of cancer and high-grade cancer when HGPIN or atypical glands are detected on initial biopsy. Fortunately, data from the past decade have shed light on these phenomena, and an improved understanding of the implications of the presence of HGPIN and atypical glands on prostate biopsy means that clinical recommendations can be made for the management of patients with these diagnoses.

Typing the atypical: Diagnostic issues and predictive markers in suspicious prostate lesions

As much as 5% of prostate biopsies yield findings equivocal for malignancy even for skilled uropathologist; such "grey zone" lesions have been addressed in many ways, although the acronym ASAP (atypical small acinar proliferation) is the most widely used when referring to an atypical focus suspicious, but not diagnostic, for malignancy. Since the introduction of this diagnostic category more than 20 years ago, debate has ensued over its histological characterization and clinical significance. Pathology reporting of ASAP, commonly based on strict morphological criteria and traditional immunohistochemical markers such as basal cell antibodies, has been improved by recent availability of novel immunohistochemical markers such as AMACR and ERG. Further pathological issues, such as the role of pre-analytical variables, number of tissue levels, interobserver variability, and association with prostatic intraepithelial neoplasia also play a role in the optimal assessment of ASAP. Apart from diagnostic issues, a major issue is ASAP predictive value for prostate cancer on repeat biopsy. Therefore, attempts have been made to identify clinical and biological parameters that could predict subsequent diagnosis of malignancy as well as define time and modality of repeat biopsy. Finally, pathological features of cancers detected after a previous ASAP diagnosis are compared with those diagnosed at first prostate biopsy.

Prostate atypia: does repeat biopsy detect clinically significant prostate cancer?

BACKGROUND

While the treatment pathway in response to benign or malignant prostate biopsies is well established, there is uncertainty regarding the risk of subsequently diagnosing prostate cancer when an initial diagnosis of prostate atypia is made. As such, we investigated the likelihood of a repeat biopsy diagnosing prostate cancer (PCa) in patients in which an initial biopsy diagnosed prostate atypia.

METHODS

We reviewed our prospectively maintained prostate biopsy database to identify patients who underwent a repeat prostate biopsy within one year of atypia (atypical small acinar proliferation; ASAP) diagnosis between November 1987 and March 2011. Patients with a history of PCa were excluded. Chart review identified patients who underwent radical prostatectomy (RP), radiotherapy (RT), or active surveillance (AS). For some analyses, patients were divided into two subgroups based on their date of service.

RESULTS

Ten thousand seven hundred and twenty patients underwent 13,595 biopsies during November 1987-March 2011. Five hundred and sixty seven patients (5.3%) had ASAP on initial biopsy, and 287 (50.1%) of these patients underwent a repeat biopsy within one year. Of these, 122 (42.5%) were negative, 44 (15.3%) had atypia, 19 (6.6%) had prostatic intraepithelial neoplasia, and 102 (35.6%) contained PCa. Using modified Epstein's criteria, 27/53 (51%) patients with PCa on repeat biopsy were determined to have clinically significant tumors. 37 (36.3%) proceeded to RP, 25 (24.5%) underwent RT, and 40 (39.2%) received no immediate treatment. In patients who underwent surgery, Gleason grade on final pathology was upgraded in 11 (35.5%), and downgraded 1 (3.2%) patient.

CONCLUSIONS

ASAP on initial biopsy was associated with a significant risk of PCa on repeat biopsy in patients who subsequently underwent definitive local therapy. Patients with ASAP should be counseled on the probability of harboring both clinically significant and insignificant prostate cancer.

Rate of Gleason 7 or higher prostate cancer on repeat biopsy after a diagnosis of atypical small acinar proliferation

BACKGROUND

Limited information is known about the clinical significance of cancers diagnosed upon repeat biopsy for the indication of atypical small acinar proliferation (ASAP). With increasing concern regarding overdiagnosis and overtreatment of prostate cancer, and the reported rise in infectious complications related to prostate biopsy, we examined the outcomes of patients rebiopsied for a diagnosis of ASAP.

METHODS

Clinical, pathologic and outcomes data of patients diagnosed with ASAP on prostate biopsy at our institutions between 2000 and 2010 were abstracted through chart review. Statistical analyses included Fisher's exact and the two-sample Wilcoxon rank sum tests. Logistic regression evaluated risk factors for the probability of cancer following a diagnosis of ASAP.

RESULTS

A total of 349 patients met the inclusion criteria with median follow-up of 4.4 years. Median age was 65.3 years with a median PSA of 5.3 ng ml(-1). Of men diagnosed with ASAP, 250/349 (71.6%) had a repeat biopsy within 1 year with 94/246 (38.2%) demonstrating prostate cancer; only 26/245 (10.6%) had ⩾Gleason 7 disease. Of men diagnosed with ASAP, 284/349 (81.4%) underwent biopsy at some time during follow-up. Prostate cancer was diagnosed in 132/279 (47.3%) of these men, 48/278 (17.3%) with ⩾Gleason 7 disease. Multivariate analyses suggested that older age, no previous biopsy and PSA density were predictive of cancer on repeat biopsy within 1 year from ASAP. Univariate analysis revealed PSA density was associated with the presence of ⩾Gleason 7 disease at 1 year and any time after a diagnosis of ASAP.

CONCLUSIONS

The overall rate of intermediate- and high-grade prostate cancer found on repeat biopsy for ASAP is low. Further investigation into ways to further risk stratify these men may be warranted. However, until such tests become available, repeat biopsy of men diagnosed with ASAP remains prudent.