Search for residual prostate cancer on pT0 radical prostatectomy after positive biopsy

Abstract

Reported incidence of no residual prostate cancer (i.e. pathological stage pT0) on radical prostatectomy ranges from 0.07 to 4.2%. The incidence is higher after neoadjuvant endocrine treatment. The aim of this study was to search for residual cancer on radical prostatectomy (RP) specimens when an initial sampling failed to find the cancer in patients with positive biopsy. Our database of 1,328 consecutive patients whose biopsies and RP specimen were both examined at the Polytechnic University-United Hospitals of the Marche Region between March 1995 and June 2006 was reviewed. The radical prostatectomies were grossly completely sampled and examined with the whole mount technique. We identified eight patients (i.e. 0.6%; three untreated and five hormonally treated preoperatively, i.e. 0.3 and 0.8%, respectively, of the total number of RPs included in the study) with positive biopsy and with no residual cancer in the initial routine histological examination of the RP. The RP of this group of eight was subjected to additional sectioning and evaluation of the paraffin blocks of the prostatectomy, also after block-flipping, immunostaining with an antibody against CAM 5.2, p63, PSA, and alpha-methylacyl-CoA racemase, and DNA specimen identity analysis. There were no cases with a false positive biopsy diagnosis, and cancer was not overlooked or missed in the initial routine histological examination of any of the 8 pT0 RPs. A minute focus of cancer (the diameter was always below 2.0 mm) was found on the additional sections in five. In particular, cancer was found after block-flipping in one of them. In an additional case, cancer was eventually discovered after immunostaining tissue sections for cytokeratin CAM 5.2, for p63 and PSA. In the remaining two cases (one untreated and the other hormonally treated), cancer was not found (0.15% of the 1,328 RPs included in the study); the review of the description of the macroscopic appearance of the RP and of its slides revealed that part of the peripheral zone corresponding to the site of the positive biopsy was missing, i.e. not removed from the patient at the time of the operation at least in one of the two. DNA specimen analysis confirmed the identity of the biopsy and prostatectomy in both. An extensive search for residual cancer reduces the number of pT0 RPs after a positive biopsy from 0.6 to 0.15%. It is recommended to have the needle biopsy reviewed, carefully look again at the radical prostatectomy, do deeper sections and then flip certain paraffin blocks. In addition, atypical foci should be stained for basal cell markers and often AMACR, especially in hormone-treated cases. If a block is missing part of the peripheral zone (capsular incision), this should be commented on. DNA analysis for tissue identity should be performed when the other steps have been taken without finding cancer.

International Society of Urological Pathology (ISUP) Consensus Conference on Handling and Staging of Radical Prostatectomy Specimens. Working group 1: specimen handling

“…[49][50][51] 56 found an incidence of 0.67% after 10-core positive biopsy to be higher than that previously reported.…”

“…[49][50][51] As an initial step, the needle biopsy should be reviewed to confirm a diagnosis of malignancy. The radical prostatectomy sections should also be reviewed in order to confirm the absence of cancer.…”

Minimal or No Residual Prostatic Adenocarcinoma on Radical Prostatectomy: A 5-Year Experience With “Vanishing Carcinoma Phenomenon”

“…[9][10][11] Mazzucchelli et al, 9 in a study of 1328 RPs, found 8 cases without residual cancer on RP, for an incidence of 0.6%. Five of these cases were from hormonally treated patients and only 3 from untreated patients.…”

“…Furthermore, because the possibility of capsular incision in some cases of VC exists (referring to the urologist's transecting either benign or malignant prostatic tissue, consequently leaving prostate or tumor behind), 18 the pathologist should discuss this possibility with the urologist or comment on the pathology report. 9 Finally, a specimen mix-up is another possibility for not finding residual cancer on RP. If significant amount of carcinoma, especially high grade (Gleason score .7), with perineural invasion on the needle biopsy is found and there is no tumor on the RP specimen, switching of the biopsy specimen should be investigated, ideally using molecular tests.…”

Biopsy Misidentification Identified by DNA Profiling in a Large Multicenter Trial

“…Few studies have been published that document the use of DNA profiling to identify prostate biopsy identity errors. 1,[5][6][7][8] In most of these studies, DNA profiling was only used for patients in whom cancer could not be identified within the prostatectomy surgical specimen (pT0 patients) despite testing positive by needle biopsy. Moreover, the number of patients for whom DNA identity profiling was performed in these studies was small, ranging from two to six patients.…”