Predictive factors of unfavorable prostate cancer in patients who underwent prostatectomy but eligible for active surveillance

Diagnostic Accuracy of Contemporary Selection Criteria in Prostate Cancer Patients Eligible for Active Surveillance: A Bayesian Network Meta-Analysis

Background

Several active surveillance (AS) criteria have been established to screen insignificant prostate cancer (insigPCa, defined as organ confined, low grade and small volume tumors confirmed by postoperative pathology). However, their comparative diagnostic performance varies. The aim of this study was to compare the diagnostic accuracy of contemporary AS criteria and validate the absolute diagnostic odds ratio (DOR) of optimal AS criteria.

Methods

First, we searched Pubmed and performed a Bayesian network meta-analysis (NMA) to compare the diagnostic accuracy of contemporary AS criteria and obtained a relative ranking. Then, we searched Pubmed again to perform another meta-analysis to validate the absolute DOR of the top-ranked AS criteria derived from the NMA with two endpoints: insigPCa and favorable disease (defined as organ confined, low grade tumors). Subgroup and meta-regression analyses were conducted to identify any potential heterogeneity in the results. Publication bias was evaluated.

Results

Seven eligible retrospective studies with 3,336 participants were identified for the NMA. The diagnostic accuracy of AS criteria ranked from best to worst, was as follows: Epstein Criteria (EC), Yonsei criteria, Prostate Cancer Research International: Active Surveillance (PRIAS), University of Miami (UM), University of California-San Francisco (UCSF), Memorial Sloan-Kettering Cancer Center (MSKCC), and University of Toronto (UT). I² = 50.5%, and sensitivity analysis with different insigPCa definitions supported the robustness of the results. In the subsequent meta-analysis of DOR of EC, insigPCa and favorable disease were identified as endpoints in ten and twenty-two studies, respectively. The pooled DOR for insigPCa and favorable disease were 0.44 (95%CI, 0.31–0.58) and 0.66 (95%CI, 0.61–0.71), respectively. According to a subgroup analysis, the DOR for favorable disease was significantly higher in US institutions than that in other regions. No significant heterogeneity or evidence of publication bias was identified.

Conclusions

Among the seven AS criteria evaluated in this study, EC was optimal for positively identifying insigPCa patients. The pooled diagnostic accuracy of EC was 0.44 for insigPCa and 0.66 when a more liberal endpoint, favorable disease, was used.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/], PROSPERO [CRD42020157048].

Comparative rates of upstaging and upgrading in Caucasian and Korean prostate cancer patients eligible for active surveillance

Purpose

To investigate the impact of race on the risk of pathological upgrading and upstaging at radical prostatectomy (RP) in an Asian (Korean) and Western (Caucasian) cohort eligible for active surveillance (AS).

Materials and methods

We performed a retrospective cohort study of 854 patients eligible for AS who underwent RP in United States (n = 261) and Korea (n = 593) between 2006 and 2015. After adjusting for age, PSA level, and prostate volume, we utilized multivariate logistic regression analysis to assess the effect of race on upgrading or upstaging.

Results

There were significant differences between Caucasian and Korean patients in terms of age at surgery (60.2 yr. vs. 64.1 yr.), PSA density (0.115 ng/mL/mL vs. 0.165 ng/mL/mL) and mean number of positive cores (3.5 vs. 2.4), but not in preoperative PSA values (5.11 ng/mL vs. 5.05 ng/mL). The rate of upstaging from cT1 or cT2 to pT3 or higher was not significantly different between the two cohorts (8.8% vs. 11.0%, P = 0.341). However, there were higher rates of upgrading to high-grade cancer (Gleason 4+3 or higher) in Korean patients (9.1%) when compared to Caucasian counterparts (2.7%) (P = 0.003). Multivariate logistic regression analysis showed that age (OR 1.07, P < 0.001) and smaller prostate volume (OR 0.97, P < 0.001), but not race, were significantly associated with upstaging or upgrading.

Conclusions

There were no differences in rates of upgrading or upstaging between Caucasian and Korean men eligible for active surveillance.

Selection Criteria for Active Surveillance of Patients with Prostate Cancer in Korea: A Multicenter Analysis of Pathology after Radical Prostatectomy

Purpose

Korean patients with prostate cancer (PC) typically present with a more aggressive disease than patients in Western populations. Consequently, it is unclear if the current criteria for active surveillance (AS) can safely be applied to Korean patients. Therefore, this study was conducted to define appropriate selection criteria for AS for patients with PC in Korea.

Materials and Methods

We conducted a multicenter retrospective study of 2,126 patients with low risk PC who actually underwent radical prostatectomy. The primary outcome was an unfavorable disease, which was defined by non-organ confined disease or an upgrading of the Gleason score to ≥ 7 (4+3). Predictive variables of an unfavorable outcome were identified by multivariate analysis using randomly selected training samples (n=1,623, 76.3%). We compared our selected criteria to various Western criteria for the primary outcome and validated our criteria using the remaining validation sample (n=503, 23.7%).

Results

A non-organ confined disease rate of 14.9% was identified, with an increase in Gleason score ≥ 7 (4+3) of 8.7% and a final unfavorable disease status of 20.8%. The following criteria were selected: Gleason score ≤ 6, clinical stage T1-T2a, prostate-specific antigen (PSA) ≤ 10 ng/mL, PSA density < 0.15 ng/mL/mL, number of positive cores ≤ 2, and maximum cancer involvement in any one core ≤ 20%. These criteria provided the lowest unfavorable disease rate (11.7%) when compared to Western criteria (13.3%-20.7%), and their validity was confirmed using the validation sample (5.9%).

Conclusion

We developed AS criteria which are appropriate for Korean patients with PC. Prospective studies using these criteria are now warranted.

Identification of candidates for observation

PURPOSE OF REVIEW

The clinical value of active surveillance may still be limited due to acceptance and considerable misclassification rates, and inadequate follow-up criteria. This review focuses on the most recent developments in the use of active surveillance and patient-specific factors that may be used to identify patients suitable for this strategy.

RECENT FINDINGS

The number of patients diagnosed with low-risk prostate cancer has risen. Active surveillance acceptance rates are increasing, but still limited and varying importantly (2-49%). Misclassification is inevitable in all currently used protocols, although most of these patients still have relatively favorable-risk prostate cancer. African-American race, obese, and older-aged patients show more unfavorable intermediate results in an active surveillance situation. These are unlikely to be explained by the small differences in preoperative characteristics only. Psychological profiling may also be added to the selection process. Most studies report intermediate endpoints only.

SUMMARY

Patient-specific factors may be incorporated when identifying patients for active surveillance. This does not imply that active surveillance is not justified in specific groups, but may suggest the need for an intensified and personalized selection, instead of a one-size-fits-all approach.

Current status of active surveillance in prostate cancer

Active surveillance (AS) is a management strategy involving close monitoring the course of disease with the expectation to intervene if the cancer progress, in a super-selected group of low-risk prostate cancer (PCa) patients. Determining AS candidates should be based on careful individualized weighing of numerous factors: life expectancy, general health condition, disease characteristics, potential side effects of treatment, and patient preference. Several protocols have been developed to determine insignificant PCa for choosing ideal AS candidates. Results regarding disease reclassification during AS have been also reported. In an effort to enhance accuracy during selection of AS candidate, there were several reports on using magnetic resonance imaging for prediction of insignificant PCa. Currently, there is an urgent need for further clinical studies regarding the criteria for recommending AS, the criteria for reclassification on AS, and the schedule for AS. Considering the racial differences in behavior of PCa between Western and Asian populations, more stringent AS protocols for Asian patients should be established from additional, well-designed, large clinical studies.