Prediction of biochemical recurrence after robot‐assisted radical prostatectomy: Analysis of 784 Japanese patients

Abstract

Abbreviations & Acronyms BCR = biochemical recurrence BCRFS = biochemical recurrence-free survival CI = confidence interval HR = hazard ratio IQR = interquartile range PSA = prostate-specific antigen PSAD = prostate-specific antigen density PSM = positive surgical margin RARP = robot-assisted radical prostatectomy RP = radical prostatectomy RR = relative risk Objectives: To examine biochemical recurrence after robot-assisted radical prostatectomy in Japanese patients, and to develop a risk stratification model for biochemical recurrence. Methods: The study cohort consisted of 784 patients with localized prostate cancer who underwent robot-assisted radical prostatectomy without neoadjuvant or adjuvant endocrine therapy. The relationships of biochemical recurrence with perioperative findings were evaluated. The prognostic factors for biochemical recurrence-free survival were evaluated using Cox proportional hazard model analyses. Results: During the follow-up period, 80 patients showed biochemical recurrence. The biochemical recurrence-free survival rates at 1, 3, and 5 years were 92.2%, 85.2% and 80.1%, respectively. In univariate analysis, the prostate-specific antigen level, prostate-specific antigen density, biopsy Gleason score, percent positive core, pathological T stage, pathological Gleason score, lymphovascular invasion, perineural invasion and positive surgical margin were significantly associated with biochemical recurrence. In multivariate analysis, prostatespecific antigen density ≥0.4 (P = 0.0011), pathological T stage ≥3a (P = 0.002), pathological Gleason score ≥8 (P = 0.007) and positive surgical margin (P < 0.0001) were independent predictors of biochemical recurrence. The patients were stratified into three risk groups according to these factors. The 5-year biochemical recurrence-free survival rate was 89.4% in the low-risk group, 65.6% in the intermediate-risk group and 30.3% in the high-risk group. Conclusions: The prostate-specific antigen density, pathological T stage, pathological Gleason score and positive surgical margin were independent prognostic factors for biochemical recurrence. The risk stratification model developed using these four factors could help clinicians identify patients with a poor prognosis who might be good candidates for clinical trials of alternative management strategies.

Perineural Invasion and Risk of Lethal Prostate Cancer

“…This is likely explained by the fact that we used a strict definition of PNI, that of circumferential encirclement of nerves by malignant glands. In contrast, prior studies reporting a higher PNI prevalence either did not describe how PNI was defined (14, 19, 20, 25, 39) or used vague descriptions such as presence of tumor cells “in the perineural space” (16, 18) or “along the perineural sheath” (21). Because the perineural space can often be difficult to identify using H&E stains alone, abutment of the perineural space by both malignant and benign glands can, in the absence of circumferential involvement, be misinterpreted as PNI (53, 54), resulting in misclassification.…”

Validation of active surveillance criteria for pathologically insignificant prostate cancer in Asian men

“…Although most of the protocols have been shown to accurately select low‐risk, organ‐confined prostate cancer, significant discrepancies between diagnostic biopsy and the surgical specimens have also been reported as a result of Gleason score upgrading and upstaging . Furthermore, the clinicopathological differences between Asia and Western countries have also been documented . Therefore, current AS protocols validated in the USA and Western Europe might not fit in the Asian population.…”

Editorial Comment to Prediction of biochemical recurrence after robot‐assisted radical prostatectomy: Analysis of 784 Japanese patients

“…The authors studied the probability of biochemical recurrence (BCR) post‐robot‐assisted radical prostatectomy (RARP) against a group of Japanese patients, and developed a Japanese risk stratification model for BCR. From this group, the authors identified prostate‐specific antigen density, pathological T stage, Gleason score and positive surgical margin as the risk factors for BCR . This study showed a new risk stratification model by the combinations of these risk factors based on the data of the Japanese (and Asian) group, which is different to a Caucasian group.…”