Editorial Comment to Characterization and risk stratification of prostate cancer in patients undergoing radical cystoprostatectomy

Abstract

Radical cystoprostatectomy (RPE) with bilateral lymph node dissection and urinary diversion is the treatment of choice in muscle-invasive bladder cancer. Standard cystectomy includes en bloc prostatectomy providing the best oncological control, but is associated with substantial reduction of quality of life. The two main concerns regarding the functional results of this surgical method are affected continence and sexual function. Therefore, various modifications to standard cystectomy have been used to improve functional outcomes. All of these techniques aim to minimize dissection near the urinary sphincter and neurovascular bundles during cystectomy by partial or complete sparing of the prostate, seminal vesicles and vasa deferentia. These methods provided a remarkable improvement of functional results. 1 In contrast, leaving whole or part of the prostate behind raises concerns on oncological results.The two main risks of prostate-sparing cystectomy are overseeing a possible prostatic urothelial carcinoma and/or occult primary prostate cancer (PCA) in these patients. The rationale for this is that both urothelial carcinoma and PCA were reported to be frequent incidental findings in RPE specimens. In the absence of randomized clinical trials, the direct comparison of oncological risks between RPE and prostate-sparing cystectomy is not possible. Therefore, critical analysis of single risk factors and their combinations described in different retrospective studies remains the only way to draw conclusions regarding the risks of various cystectomy methods. This present study 2 is the largest to date assessing the prevalence and risk of occult PCA in patients treated with RPE. Buse et al. found PCA in 18% of RPE specimens, which is at the lower end of the PCA prevalence published so far. The rate of high-risk PCA was <2% over the whole patient cohort, and is ~10% of all detected PCAs, showing that most identified PCA in RPE specimens are clinically indolent. Formerly, Thomas et al. showed that preoperatively available predictors, such as serum prostate-specific antigen level and digital rectal examination are able to sensitively identify clinically significant PCA before radical surgery. 3 However, others drew different conclusions. 4 Therefore, as oncological results have to overweigh functional outcomes, careful selection for prostate-sparing surgery remains important. Using strict selection criteria for prostate-sparing cystectomy, de Vries et al. were able to reach comparable oncological results to that of standard RPE. 5 However, such strict inclusion criteria substantially reduce the availability of this technique. More accurate risk stratification is therefore required to increase availability with maintained oncological efficacy. A further interesting finding of the study by Buse et al. 2 was the independent and unfavorable prognostic value of the presence of PCA in RPE specimens. Unfortunately, data on cause of death were not available; therefore, the authors were not able to conclude whether the additional risk by PCA is a result of the PCA-related deaths. However, the low prevalence of high-risk PCA found in the present study suggests that the additional risk by the presence of PCA is independent from PCA-related deaths. Based on this, it can be presumed that concomitant PCA supports bladder cancer progression. However, more convincing clinical and molecular evidence is required to confirm this hypothesis.