The Impact of Prostate Cancer Zonal Origin on Pathological Parameters at Radical Prostatectomy and Subsequent Biochemical Failure - Beyond the Abstract

Of all patients who undergo radical prostatectomy (RP), 20% of tumors are located in the transitional zone (TZ) of the prostate1,2. These tumors are historically diagnosed at higher PSA values and with larger tumor volumes compared to peripheral neoplasms, which is likely due to its anterior location on the prostate making it difficult to detect via a digital rectal exam. With the advent of prostatic multiparametric magnetic resonance imaging (mpMRI) and transperineal prostatic biopsy, carcinomas of the TZ are being found with increasing accuracy leading to earlier surgical intervention3,4. However, the impact of prostatic tumor location is widely debated since some studies have shown no difference between TZ and peripheral zone (PZ) tumors5,6. The primary aim of this study was to investigate the impact of cancer zonal origin, particularly in the TZ, on accepted pathological prognostic features and subsequent biochemical outcomes. These results were then compared to the combination of peripheral and central zone (CZ) carcinomas

Through a retrospective analysis of the Western Australia RP database, 7,051 patients were identified to have undergone RP with curative intent between September 1998 and December 2016. Specimens collected from the extirpative procedure were preserved, sectioned, and stained for measurements while computerized image analysis assessed tumor volume. The patients were divided into two cohorts based on high-grade disease (Gleason sum 4 + 3, 8 and 9 or greater, and ISUP groups 3, 4, and 5) and low grade (Gleason sum 5 or less and 3 + 4, and ISUP groups 1 and 2). 

The high-grade disease was present in a total of 2,677 patients including 2,404 with PZ/CZ carcinomas and 273 with TZ neoplasms; low-grade disease was present in 3,275 and 1,099 patients with PZ/CZ and TZ carcinomas, respectively. The high-grade TZ cohort was shown to have a significantly higher mean PSA, tumor volume, and positive surgical margin (PSM) than the PZ/CZ cohort. Additionally, the TZ group had a significantly lower incidence of intraductal carcinoma (IDCP), extraprostatic spread (EPS), seminal vesical invasion (SVI), lymph node involvement, and biochemical recurrence (BCR). All patients within the low-grade cohort had excellent BCR-free survival regardless of tumor origin. 

In conclusion, it was found that prostate cancer zonal origin significantly impacts biochemical outcomes in patients with high-grade prostate cancer. TZ carcinomas were shown to result in better BCR-free survival after adjustments for adverse clinicopathological features. 

Written by: Zhamshid Okhunov, MD, University of California Irvine

References
  1. Augustin H, Hammerer PG, Blonski J et al: Zonal location of prostate cancer: significance for disease-free survival after radical prostatectomy? Urology 2003; 62: 79.
  2. Iremashvili V, Pelaez L, Jord a M et al: Prostate cancers of different zonal origin: clinicopathological characteristics and biochemical outcome after radical prostatectomy. Urology 2012; 80: 1063.a MIremashvili V, Pelaez L, Jord a M et al: Prostate cancers of different zonal origin: clinicopathological characteristics and biochemical outcome after radical prostatectomy. Urology 2012; 80: 1063.
  3. Lee S, Walsh S, Woods CG et al: Reliable identification of transition zone prostatic adenocarcinoma in preoperative needle core biopsy. Hum Pathol 2013; 44: 2331.
  4. Rais-Bahrami S, Siddiqui MM, Turkbey B et al: Utility of multiparametric magnetic resonance imaging suspicion levels for detecting prostate cancer. J Urol 2013; 190: 1721.
  5. King CR, Ferrari M and Brooks JD: Prognostic significance of prostate cancer originating from the transition zone. Urol Oncol 2009; 27: 592.
  6. Lee JJ, Thomas IC, Nolley R et al: Biologic difference between peripheral and transition zone prostate cancer. Prostate 2015; 75: 183.
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