Untreated Gleason Grade Progression on Serial Biopsies during Prostate Cancer Active Surveillance: Clinical Course and Pathological Outcomes

Polygenic Risk Score and Upgrading in Patients With Prostate Cancer Receiving Active Surveillance

Importance

Active surveillance is the preferred management strategy for patients with low- or favorable intermediate-risk prostate cancer (PCa); however, frequent health care visits can be costly and burdensome to patients. Identifying patients who may benefit from intensive vs passive surveillance could reduce these burdens.

Objective

To investigate associations between a polygenic risk score (PRS) and risk of upgrading and other prostate tumor features in patients receiving active surveillance.

Design, Setting, and Participants

This prospective multicenter cohort study across 10 US sites included 1220 patients from the Canary Prostate Active Surveillance Study (PASS) enrolled from July 2008 to November 2017, with follow-up (median, 5.3 years) through August 2022. Participants were those with clinically localized PCa (cT1-T2) receiving active surveillance. Analyses took place from January 2023 to April 2024.

Exposure

Multi-ancestry PRS of 451 PCa risk variants (PRS-451) and 400 PCa risk variants (PRS-400) after excluding prostate-specific antigen (PSA)-associated variants.

Main Outcomes and Measures

The primary outcome was PCa upgrading (any Gleason grade increase) vs no upgrading. Secondary outcomes included prostate volume, PSA, PSA density, percentage of biopsy cores with cancer, and Gleason grade group at diagnosis.

Results

The median (IQR) age at diagnosis of the 1220 patients receiving active surveillance was 63 (58-67) years. During follow-up, 470 patients upgraded; the 2- and 5-year risks of upgrading were 17.7% (95% CI, 15.5%-19.9%) and 33.3% (95% CI, 30.5%-36.3%), respectively. Each 1-SD unit increase in PRS-451 was associated with 23% increased hazard of upgrading (95% CI, 1.11-1.35; P < .001), whereas PRS-400 was associated with 27% increased hazard (95% CI, 1.15-1.39; P < .001) at any point in time during follow-up. Except for PSA, associations with remaining outcomes were similar or stronger using PRS-400. Higher PRS-400 was associated with smaller prostate volume, a higher percentage of biopsy cores with cancer, and higher PSA density. A model with clinical risk factors had a C-index of 0.64 (95% CI, 0.62-0.67); adding PRS-400 led to a C-index of 0.65 (95% CI, 0.63-0.68).

Conclusions and Relevance

In this cohort study, among patients receiving active surveillance, high PRS was associated with risk of upgrading and possibly tumor multifocality. Excluding PSA variants from the PRS revealed an association with smaller prostate size, which has been previously associated with more aggressive tumors. Although PRS may inform active surveillance, it is yet to be seen whether they improve clinical decisions.

Prospective Observational Study of a Racially Diverse Group of Men on Active Surveillance for Prostate Cancer

OBJECTIVE

To evaluate the risk upgrading of active surveillance (AS), we reviewed the outcomes of African American men (AA) after electing AS. AS is the standard of care for men with low-grade prostate cancer (PCa). AA are known to have more advanced PCa features and are more likely to die from PCa, thus subsequent disease progression for AA on AS is unclear.

METHODS

A prospectively maintained AS database from the Southeast Louisiana Veterans Administration Medical Center, New Orleans, Lousiana was queried. We identified men with low- and very low-risk PCa (Gleason 3 + 3, PSA <10, ≤CT2a) who had undergone at least 2 prostate biopsies, including initial diagnostic and subsequent confirmatory prostate biopsies. Descriptive and comparative statistical analysis was performed using R version 3.5.1.

RESULTS

From a total of 274 men on AS (70% AA), 158 men met inclusion criteria (104 AA [66%]). All patients underwent at least 2 biopsies, and 29% underwent 3 or more biopsies. The median follow-up was 2.7 years. At 3 years on AS protocol, 57% AA and 61% Caucasians demonstrated no evidence of upgrading or treatment. No significant difference was observed between upgrading or progression to treatment when comparing racial groups. Seven (4%) patients in this cohort died from non PCa-specific causes, but no patients demonstrated metastasis or death from PCa over the course of study.

CONCLUSION

AA men with low-risk PCa can be safely followed with the same AS protocol as non-AA men. Further analysis with longer follow up is ongoing.

Defining and Measuring Adherence in Observational Studies Assessing Outcomes of Real-world Active Surveillance for Prostate Cancer: A Systematic Review

CONTEXT

Evidence-based guidelines for active surveillance (AS), a treatment option for men with low-risk prostate cancer, recommend regular follow-up at periodic intervals to monitor disease progression. However, gaps in monitoring can lead to delayed detection of cancer progression, leading to a missed window of curability.

OBJECTIVE

We aimed to identify the extent to which real-world observational studies reported adherence to monitoring protocols among prostate cancer patients on AS. When reported, we sought to characterize definitions of adherence.

EVIDENCE ACQUISITION

We systematically reviewed observational studies assessing outcomes of prostate cancer patients on AS, published before March 22, 2019 in PubMed, Embase, and CENTRAL. Adherence definitions were considered time bound if they included prespecified time and binary if adherence was assessed but did not specify a time interval. We assessed study quality using the Strengthening the Reporting of Observational Studies in Epidemiology checklist.

EVIDENCE SYNTHESIS

Forty-five studies met our inclusion criteria. Eleven studies did not report any data on adherence to AS protocols. Twenty-five studies did not explicitly measure adherence, but provided relevant data (eg, number of patients who received a repeat biopsy). Six studies reported adherence using a time-bound definition, while three studies used a binary definition. Twenty-three studies provided information on patients lost to follow-up.

CONCLUSIONS

Most studies reporting outcomes of patients on AS did not measure or report adherence. When reported, adherence was often not time specific. As some AS patients will benefit from maintaining a window of curability, clinical practices and future studies should track and report adherence and associated factors.

PATIENT SUMMARY

We reviewed real-world observational studies examining outcomes of prostate cancer patients on active surveillance. Most studies did not clearly define or report adherence to monitoring protocols, which is important to consider for appropriate disease management.

Active Surveillance in Younger Men With Prostate Cancer

Purpose The suitability of younger patients with prostate cancer (PCa) for initial active surveillance (AS) has been questioned on the basis of eventual treatment necessity and concerns of safety; however, the role of age on surveillance outcomes has not been well defined. Patients and Methods We identified men managed with AS at our institution with a minimum follow-up of 6 months. The primary study objective was to examine the association of age with risk of biopsy-based Gleason score upgrade during AS. We also examined the association of age with related end points, including overall biopsy-determined progression, definitive treatment, and pathologic and biochemical outcomes after delayed radical prostatectomy (RP), using descriptive statistics, the Kaplan-Meier method, and multivariable Cox proportional hazards regression. Results A total of 1,433 patients were followed for a median of 49 months; 74% underwent initial biopsy at a referring institution. Median age at diagnosis was 63 years, including 599 patients (42%) ≤ 60 years old and 834 (58%) > 60 years old. The 3- and 5-year biopsy-based Gleason score upgrade-free rates were 73% and 55%, respectively, for men ≤ 60 years old compared with 64% and 48%, respectively, for men older than 60 years ( P < .01). On Cox regression analysis, younger age was independently associated with lower risk of biopsy-based Gleason score upgrade (hazard ratio per 1-year decrease, 0.969 [95% CI, 0.956 to 0.983]; P < .01), and persisted upon restriction to men meeting strict AS inclusion criteria. There was no significant association between younger age and risk of definitive treatment or risk of biochemical recurrence after delayed RP. Conclusion Younger patient age was associated with decreased risk of biopsy-based Gleason score upgrade during AS but not with risk of definitive treatment in the intermediate term. AS represents a strategy to mitigate overtreatment in young patients with low-risk PCa in the early term.

Timing of Adverse Prostate Cancer Reclassification on First Surveillance Biopsy: Results from the Canary Prostate Cancer Active Surveillance Study

PURPOSE

During active surveillance for localized prostate cancer, the timing of the first surveillance biopsy varies. We analyzed the Canary PASS (Prostate Cancer Active Surveillance Study) to determine biopsy timing influence on rates of prostate cancer adverse reclassification at the first active surveillance biopsy.

MATERIALS AND METHODS

Of 1,085 participants in PASS, 421 had fewer than 34% of cores involved with cancer and Gleason sum 6 or less, and thereafter underwent on-study active surveillance biopsy. Reclassification was defined as an increase in Gleason sum and/or 34% or more of cores with prostate cancer. First active surveillance biopsy reclassification rates were categorized as less than 8, 8 to 13 and greater than 13 months after diagnosis. Multivariable logistic regression determined association between reclassification and first biopsy timing.

RESULTS

Of 421 men, 89 (21.1%) experienced reclassification at the first active surveillance biopsy. Median time from prostate cancer diagnosis to first active surveillance biopsy was 11 months (IQR 7.8-13.8). Reclassification rates at less than 8, 8 to 13 and greater than 13 months were 24%, 19% and 22% (p = 0.65). On multivariable analysis, compared to men biopsied at less than 8 months the OR of reclassification at 8 to 13 and greater than 13 months were 0.88 (95% CI 0.5,1.6) and 0.95 (95% CI 0.5,1.9), respectively. Prostate specific antigen density 0.15 or greater (referent less than 0.15, OR 1.9, 95% CI 1.1, 4.1) and body mass index 35 kg/m² or greater (referent less than 25 kg/m², OR 2.4, 95% CI 1.1,5.7) were associated with increased odds of reclassification.

CONCLUSIONS

Timing of the first active surveillance biopsy was not associated with increased adverse reclassification but prostate specific antigen density and body mass index were. In low risk patients on active surveillance, it may be reasonable to perform the first active surveillance biopsy at a later time, reducing the overall cost and morbidity of active surveillance.

Prostate Cancer Diagnosis on Repeat Magnetic Resonance Imaging-Transrectal Ultrasound Fusion Biopsy of Benign Lesions: Recommendations for Repeat Sampling

PURPOSE

Urologists face a dilemma when a lesion identified on multiparametric magnetic resonance imaging is benign on image guided fusion biopsy. We investigated the detection rate of prostate cancer on repeat fusion biopsy in multiparametric magnetic resonance imaging lesions initially found to be pathologically benign on fusion biopsy.

MATERIALS AND METHODS

We reviewed the records of all patients from 2007 to 2014 who underwent multiparametric magnetic resonance imaging and image guided fusion biopsy. We identified men who underwent rebiopsy of the same discrete lesion after initial fusion biopsy results were benign. Data were documented on a per lesion basis. We manually reviewed UroNav system (Invivo, Gainesville, Florida) needle tracking to verify accurate image registration. Multivariate analysis was used to identify clinical and imaging factors predictive of prostate cancer detection at repeat fusion biopsy.

RESULTS

A total of 131 unique lesions were rebiopsied in 90 patients. Of these 131 resampled lesions 21 (16%) showed prostate cancer, which in 13 (61.9%) was Gleason 3 + 3. On multivariate analysis only lesion growth on repeat multiparametric magnetic resonance imaging was significantly associated with prostate cancer detection at repeat biopsy (HR 3.274, 95% CI 1.205-8.896, p = 0.02).

CONCLUSIONS

Pathologically benign multiparametric magnetic resonance imaging lesions on initial image guided fusion biopsy are rarely found to harbor clinically significant prostate cancer on repeat biopsy. When prostate cancer was identified, most disease was low risk. An increase in lesion diameter was an independent predictor of prostate cancer detection. While these data are retrospective, they may provide some confidence in the reliability of negative initial image guided fusion biopsies despite a positive multiparametric magnetic resonance imaging finding.

Disease reclassification risk with stringent criteria and frequent monitoring in men with favourable-risk prostate cancer undergoing active surveillance

OBJECTIVES

To determine the frequency of disease reclassification and to identify clinicopathological variables associated with it in patients with favourable-risk prostate cancer undergoing active surveillance (AS).

PATIENTS AND METHODS

We assessed 191 men, selected by what may be the most stringent criteria used in AS studies yet conducted, who were enrolled in a prospective cohort AS trial. Clinicopathological characteristics were analysed in a multivariate Cox proportional hazards regression model. Key features were an extended biopsy with a single core positive for Gleason score (GS) 3 + 3 (<3 mm) or 3 + 4 (<2 mm) and a prostate-specific antigen (PSA) level <4 ng/mL (adjusted for prostate volume). Biopsies were repeated every 1-2 years and clinical evaluations every 6 months. Disease was reclassified when PSA level increased by 30% from baseline, or when biopsy tumour length increased beyond the enrolment criteria, more than one positive core was detected or any grade increased to a dominant 4 pattern or any 5 pattern.

RESULTS

Disease was reclassified in 32 patients (16.8%) including upgrading to GS 4 + 3 in five patients (2.6%). The median (interquartile range) follow-up time among survivors was 3 (1.9-4.6) years. Overall, 13 of the 32 (40.6%) had incremental increases in GS. Tumour length (hazard ratio 2.95, 95% confidence interval [CI] 1.34-6.46; P = 0.007) and older age (hazard ratio 1.05, 95% CI 1.00-1.09; P = 0.05) were identified as significant and marginally significant predictors of disease reclassification, respectively. Disease remained stable in 83.2% of patients.

CONCLUSION

The need persists for improvements in risk stratification and predictive indicators of cancer progression.