Incidence and location of prostate and urothelial carcinoma in prostates from cystoprostatectomies: implications for possible apical sparing surgery.

PURPOSE: Prostatic carcinoma (Pca) at cystoprostatectomy is usually an incidental finding with the majority thought to be clinically insignificant. Most studies have not specifically addressed the location of Pca or the incidence and location of in situ or invasive urothelial carcinoma (Uca) in prostates of cystoprostatectomy specimens. The frequency of involvement of the apex with these processes has clinical implications. Specifically urinary continence following orthotopic diversion may be enhanced by prostate apical sparing. In this study the pathological features of Pca and Uca, and the frequency of apical involvement were investigated in prostates from cystoprostatectomy specimens. MATERIALS AND METHODS: Whole mounted prostates from 121 consecutive cystoprostatectomy specimens were analyzed. Pca location, tumor volume, grade, stage, surgical margin and pelvic lymph node status of Pcas were assessed. Clinically insignificant Pcas had a volume of less than 0.5 cc without Gleason pattern 4, extracapsular extension, seminal vesicle invasion, lymph node involvement or positive surgical margins. Prostate involvement by Uca or urothelial carcinoma in situ (CIS)/severe dysplasia and its location were assessed. RESULTS: Of 121 prostates 50 (41%) had unsuspected Pca, of which 24 (48%) were clinically significant. Of Pcas 30 of 50 (60%) involved the apex, including 19 of 24 (79%) that were significant and 11 of 26 (42%) that were insignificant. Of 121 prostates 58 (48%) had Uca involving the prostatic stroma, noninvasive Uca or urothelial CIS/severe dysplasia in the prostatic urethra or periurethral ducts, of which 19 (33%) had apical involvement. Overall only 32 of 121 patients (26%) had no Pca or prostate Uca/CIS and only 45 (37%) had no clinically significant Pca or Uca/CIS in the prostate. However, 74 of the 121 patients (61%) had no prostatic apical involvement by Pca or Uca/CIS and 85 (70%) had no apical involvement by clinically significant Pca or Uca/CIS. Patients with prostatic apical involvement by invasive or in situ Uca uniformly had involvement of more proximal (toward the base) portions of the prostate. CONCLUSIONS: The majority of prostates from cystoprostatectomies had no involvement of the prostatic apex by Uca or clinically significant Pca. Hence, most patients may be candidates for prostate apical sparing. However, involvement of the apex by Uca in any patient raises concern about procedures that leave portions of the prostate urethra after cystectomy in an effort to improve continence. In candidates for orthotopic neobladder reconstruction removing all of the prostatic urethra and sparing the remainder of the prostatic apex may allow improved preservation of urinary continence with an acceptable low risk of clinical Pca progression. Whether future strategies for preoperative exclusion of apical Pca and intraoperative assessment of more proximal prostate to help exclude apical urothelial disease may identify patients suitable for prostatic apical sparing remains to be determined. The impact on functional outcomes and cancer control also require additional study.

Incidence and location of prostate and urothelial carcinoma in prostates from cystoprostatectomies: implications for possible apical sparing surgery.

PURPOSE: Prostatic carcinoma (Pca) at cystoprostatectomy is usually an incidental finding with the majority thought to be clinically insignificant. Most studies have not specifically addressed the location of Pca or the incidence and location of in situ or invasive urothelial carcinoma (Uca) in prostates of cystoprostatectomy specimens. The frequency of involvement of the apex with these processes has clinical implications. Specifically urinary continence following orthotopic diversion may be enhanced by prostate apical sparing. In this study the pathological features of Pca and Uca, and the frequency of apical involvement were investigated in prostates from cystoprostatectomy specimens. MATERIALS AND METHODS: Whole mounted prostates from 121 consecutive cystoprostatectomy specimens were analyzed. Pca location, tumor volume, grade, stage, surgical margin and pelvic lymph node status of Pcas were assessed. Clinically insignificant Pcas had a volume of less than 0.5 cc without Gleason pattern 4, extracapsular extension, seminal vesicle invasion, lymph node involvement or positive surgical margins. Prostate involvement by Uca or urothelial carcinoma in situ (CIS)/severe dysplasia and its location were assessed. RESULTS: Of 121 prostates 50 (41%) had unsuspected Pca, of which 24 (48%) were clinically significant. Of Pcas 30 of 50 (60%) involved the apex, including 19 of 24 (79%) that were significant and 11 of 26 (42%) that were insignificant. Of 121 prostates 58 (48%) had Uca involving the prostatic stroma, noninvasive Uca or urothelial CIS/severe dysplasia in the prostatic urethra or periurethral ducts, of which 19 (33%) had apical involvement. Overall only 32 of 121 patients (26%) had no Pca or prostate Uca/CIS and only 45 (37%) had no clinically significant Pca or Uca/CIS in the prostate. However, 74 of the 121 patients (61%) had no prostatic apical involvement by Pca or Uca/CIS and 85 (70%) had no apical involvement by clinically significant Pca or Uca/CIS. Patients with prostatic apical involvement by invasive or in situ Uca uniformly had involvement of more proximal (toward the base) portions of the prostate. CONCLUSIONS: The majority of prostates from cystoprostatectomies had no involvement of the prostatic apex by Uca or clinically significant Pca. Hence, most patients may be candidates for prostate apical sparing. However, involvement of the apex by Uca in any patient raises concern about procedures that leave portions of the prostate urethra after cystectomy in an effort to improve continence. In candidates for orthotopic neobladder reconstruction removing all of the prostatic urethra and sparing the remainder of the prostatic apex may allow improved preservation of urinary continence with an acceptable low risk of clinical Pca progression. Whether future strategies for preoperative exclusion of apical Pca and intraoperative assessment of more proximal prostate to help exclude apical urothelial disease may identify patients suitable for prostatic apical sparing remains to be determined. The impact on functional outcomes and cancer control also require additional study.

Elevated expression of 12/15-lipoxygenase and cyclooxygenase-2 in a transgenic mouse model of prostate carcinoma.

Changes in expression of arachidonic acid (AA) metabolizing enzymes are implicated in the development and progression of human prostate carcinoma (Pca). Transgenic mouse models of Pca that progress from high-grade prostatic intraepithelial neoplasia (HGPIN) to invasive and metastatic carcinoma could facilitate study of the regulation and function of these genes in Pca progression. Herein we characterize the AA-metabolizing enzymes in transgenic mice established with a prostate epithelial-specific long probasin promoter and the SV40 large T antigen (LPB-Tag mice) that develop extensive HGPIN and invasive and metastatic carcinoma with neuroendocrine (NE) differentiation. Murine 8-lipoxygenase (8-LOX), homologue of the 15-LOX-2 enzyme that is expressed in benign human prostatic epithelium and reduced in Pca, was not detected in wild-type or LPB-Tag prostates as determined by enzyme assay, reverse transcription-PCR, and immunohistochemistry. The most prominent AA metabolite in mouse prostate was 12-HETE. Wild-type prostate (dorsolateral lobe) converted 1.6 +/- 0.5% [(14)C]AA to 12-HETE (n = 7), and this increased to 8.0 +/- 4.4% conversion in LPB-Tag mice with HGPIN (n = 13). Quantitative real-time reverse transcription-PCR and immunostaining correlated the increased 12-HETE synthesis with increased neoplastic epithelial expression of 12/15-LOX, the leukocyte-type (L) of 12-LOX and the murine homologue of human 15-LOX-1. Immunostaining showed increased L12-LOX in invasive carcinoma and approximately one-half of metastatic foci. COX-2 mRNA was detectable in neoplastic prostates with HGPIN but not in wild-type prostate. By immunostaining, COX-2 was increased in the neoplastic epithelium of HGPIN but was absent in foci of invasion and metastases. We conclude that (a) AA metabolism in wild-type mouse prostate differs from humans in the basal expression of LOXs (15-LOX-2 in human, absence of its 8-LOX homologue in mouse prostate); (b) increased expression of 12/15-LOX in HGPIN and invasive carcinoma of the LPB-Tag model is similar to the increased 15-LOX-1 in high-grade human Pca; and (c) the LPB-Tag model shows increased COX-2 in HGPIN, and therefore, it may allow additional definition of the role of this enzyme in the subset of human HGPINs or other precursor lesions that are COX-2 positive, as well as investigation of its contribution to neoplastic cell proliferation and tumor angiogenesis in Pca.