Long-term outcomes of active surveillance for clinically localized prostate cancer in a community-based setting: results from a prospective non-interventional study

Medium-term follow up of active surveillance for early prostate cancer at a non-academic institution

OBJECTIVES

To report oncological outcomes of active surveillance (AS) at a single non-academic institution adopting the standardised Prostate Cancer Research International Active Surveillance (PRIAS) protocol.

PATIENTS AND METHODS

Competing risk analyses estimated the incidence of overall mortality, metastases, conversion to treatment, and grade reclassification. The incidence of reclassification and adverse pathological findings at radical prostatectomy were compared between patients fulfilling all PRIAS inclusion criteria vs those not fulfilling at least one.

RESULTS

We analysed 341 men with Grade Group 1 prostate cancer (PCa) followed on AS between 2010 and 2022. There were no PCa deaths, two patients developed distant metastases and were alive at the end of the study period. The 10-year cumulative incidence of metastases was 1.9% (95% confidence interval [CI] 0.33-6.4%). A total of 111 men were reclassified, and 127 underwent definitive treatment. Men not fulfilling at least one PRIAS inclusion criteria (n = 43) had a higher incidence of reclassification (subdistribution hazards ratio 1.73, 95% CI 1.07-2.81; P = 0.03), but similar rates of adverse pathological findings at radical prostatectomy.

CONCLUSION

Metastases in men on AS at a non-academic institution are as rare as those reported in established international cohorts. Men followed without stringent inclusion criteria should be counselled about the higher incidence of reclassification and reassured they can expect rates of adverse pathological findings comparable to those fulfilling all criteria. Therefore, AS should be proposed to all men with low-grade PCa regardless of whether they are followed at academic institutions or smaller community hospitals.

Low-risk prostate lesions: An evidence review to inform discussion on losing the "cancer" label

BACKGROUND

Active surveillance (AS) mitigates harms from overtreatment of low-risk prostate lesions. Recalibration of diagnostic thresholds to redefine which prostate lesions are considered "cancer" and/or adopting alternative diagnostic labels could increase AS uptake and continuation.

METHODS

We searched PubMed and EMBASE to October 2021 for evidence on: (1) clinical outcomes of AS, (2) subclinical prostate cancer at autopsy, (3) reproducibility of histopathological diagnosis, and (4) diagnostic drift. Evidence is presented via narrative synthesis.

RESULTS

AS: one systematic review (13 studies) of men undergoing AS found that prostate cancer-specific mortality was 0%-6% at 15 years. There was eventual termination of AS and conversion to treatment in 45%-66% of men. Four additional cohort studies reported very low rates of metastasis (0%-2.1%) and prostate cancer-specific mortality (0%-0.1%) over follow-up to 15 years. Overall, AS was terminated without medical indication in 1%-9% of men. Subclinical reservoir: 1 systematic review (29 studies) estimated that the subclinical cancer prevalence was 5% at <30 years, and increased nonlinearly to 59% by >79 years. Four additional autopsy studies (mean age: 54-72 years) reported prevalences of 12%-43%. Reproducibility: 1 recent well-conducted study found high reproducibility for low-risk prostate cancer diagnosis, but this was more variable in 7 other studies. Diagnostic drift: 4 studies provided consistent evidence of diagnostic drift, with the most recent (published 2020) reporting that 66% of cases were upgraded and 3% were downgraded when using contemporary diagnostic criteria compared to original diagnoses (1985-1995).

CONCLUSIONS

Evidence collated may inform discussion of diagnostic changes for low-risk prostate lesions.

Comparison of Outcomes of Active Surveillance in Intermediate-Risk Versus Low-Risk Localised Prostate Cancer Patients: A Systematic Review and Meta-Analysis

Currently, there is no clear consensus regarding the role of active surveillance (AS) in the management of intermediate-risk prostate cancer (IRPC) patients. We aim to analyse data from the available literature on the outcomes of AS in the management of IRPC patients and compare them with low-risk prostate cancer (LRPC) patients. A comprehensive literature search was performed, and relevant data were extracted. Our primary outcome was treatment-free survival, and secondary outcomes were metastasis-free survival, cancer-specific survival, and overall survival. The DerSimonian–Laird random-effects method was used for the meta-analysis. Out of 712 studies identified following an initial search, 25 studies were included in the systematic review. We found that both IRPC and LRPC patients had nearly similar 5, 10, and 15 year treatment-free survival rate, 5 and 10 year metastasis-free survival rate, and 5 year overall survival rate. However, cancer-specific survival rates at 5, 10, and 15 years were significantly lower in IRPC compared to LRPC group. Furthermore, IRPC patients had significantly inferior long-term overall survival rate (10 and 15 year) and metastasis-free survival rate (15 year) compared to LRPC patients. Both the clinicians and the patients can consider this information during the informed decision-making process before choosing AS.

Identification of castration-dependent and -independent driver genes and pathways in castration-resistant prostate cancer (CRPC)

Background

Prostate cancer (PCa) is one of the most diagnosed cancers in the world. PCa inevitably progresses to castration-resistant prostate cancer (CRPC) after androgen deprivation therapy treatment, and castration-resistant state means a shorter survival time than other causes. Here we aimed to define castration-dependent and -independent diver genes and molecular pathways in CRPC which are responsible for such lethal metastatic events.

Methods

By employing digital gene expression (DGE) profiling, the alterations of the epididymal gene expression profile in the mature and bilateral castrated rat were explored. Then we detect and characterize the castration-dependent and -independent genes and pathways with two data set of CPRC-associated gene expression profiles publicly available on the NCBI.

Results

We identified 1,632 up-regulated and 816 down-regulated genes in rat’s epididymis after bilateral castration. Differential expression analysis of CRPC samples compared with the primary PCa samples was also done. In contrast to castration, we identified 97 up-regulated genes and 128 down-regulated genes that changed in both GEO dataset and DGE profile, and 120 up-regulated genes and 136 down-regulated genes changed only in CRPC, considered as CRPC-specific genes independent of castration. CRPC-specific DEGs were mainly enriched in cell proliferation, while CRPC-castration genes were associated with prostate gland development. NUSAP1 and NCAPG were identified as key genes, which might be promising biomarkers of the diagnosis and prognosis of CRPC.

Conclusion

Our study will provide insights into gene regulation of CRPC dependent or independent of castration and will improve understandings of CRPC development and progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12894-022-01113-5.

Adverse Pathological Findings at Radical Prostatectomy following Active Surveillance: Results from the Movember GAP3 Cohort

Background: Little is known about the consequences of delaying radical prostatectomy (RP) after Active Surveillance (AS) according to stringent or wider entry criteria. We investigated the association between inclusion criteria and rates, and timing of adverse pathological findings (APFs) among patients in GAP3 cohorts. Methods: APFs (GG ≥ 3, pT ≥ 3, pN > 0 and positive surgical margins [R1]) were accounted for in very low-risk (VLR: grade group [GG] 1, cT1, positive cores < 3, PSA < 10 ng/mL, PSA density [PSAD] < 0.15 ng/mL/cm3) and low-risk (LR: GG1, cT1-2, PSA ≤ 10 ng/mL) patients undergoing subsequent RP. The Kaplan−Meier method and log−rank test analyzed APF-free survival. Stratified mixed effects models analyzed association. Results: Out of 21,169 patients on AS, 1742 (VLR: 721; LR: 1021) underwent delayed RP. Most (60.8%) did not have APFs. APFs occurred more frequently (44.6% vs. 31.7%; OR 1.54, p < 0.001) and earlier (median time: 40.3 vs. 62.6 months; p < 0.001) in LR patients, and consisted of pT ≥ 3 (OR 1.47, p = 0.013) or R1 (OR 1.80, p < 0.001), but not of GG ≥ 3 or node involvement. Age (OR 1.05, p < 0.001), PSAD (OR 23.21, p = 0.003), and number of positive cores (OR 1.16, p = 0.004) were independently associated with APFs. Conclusions: AS stands as a safe option for low-risk patients, and most do not have APFs at surgery. Wider entry criteria are associated with pT3 and R1. The prognostic implications remain uncertain.

Two Decades of Active Surveillance for Prostate Cancer in a Single-Center Cohort: Favorable Outcomes after Transurethral Resection of the Prostate

OBJECTIVE

To report the outcomes of active surveillance (AS) for low-risk prostate cancer (PCa) in a single-center cohort.

PATIENTS AND METHODS

This is a prospective, single-center, observational study. The cohort included all patients who underwent AS for PCa between December 1999 and December 2020 at our institution. Follow-up appointments (FU) ended in February 2021.

RESULTS

A total of 413 men were enrolled in the study, and 391 had at least one FU. Of those who followed up, 267 had PCa diagnosed by transrectal ultrasound (TRUS)-guided biopsy (T1c: 68.3%), while 124 were diagnosed after transurethral resection of the prostate (TURP) (T1a/b: 31.7%). Median FU was 46 months (IQR 25-90). Cancer specific survival was 99.7% and overall survival was 92.3%. Median reclassification time was 11.2 years. After 20 years, 25% of patients were reclassified within 4.58 years, 6.6% opted to switch to watchful waiting, 4.1% died, 17.4% were lost to FU, and 46.8% remained on AS. Those diagnosed by TRUS had a significantly higher reclassification rate than those diagnosed by TURP (p < 0.0001). Men diagnosed by targeted MRI/TRUS fusion biopsy tended to have a higher reclassification probability than those diagnosed by conventional template biopsies (p = 0.083).

CONCLUSIONS

Our single-center cohort spanning over two decades revealed that AS remains a safe option for low-risk PCa even in the long term. Approximately half of AS enrollees will eventually require definitive treatment due to disease progression. Men with incidental prostate cancer were significantly less likely to have disease progression.

[MRI-guided minimally invasive treatment of prostate cancer]

CLINICAL/METHODOLOGICAL ISSUE

Multiparametric magnetic resonance imaging (mpMRI) of the prostate plays a crucial role in the diagnosis and local staging of primary prostate cancer.

STANDARD RADIOLOGICAL METHODS

Image-guided biopsy techniques such as MRI-ultrasound fusion not only allow guidance for targeted tissue sampling of index lesions for diagnostic confirmation, but also improve the detection of clinically significant prostate cancer.

METHODOLOGICAL INNOVATIONS

Minimally invasive, focal therapies of localized prostate cancer complement the treatment spectrum, especially for low- and intermediate-risk patients.

PERFORMANCE

In patients of low and intermediate risk, MR-guided, minimally invasive therapies could enable local tumor control, improved functional outcomes and possible subsequent therapy escalation. Further study results related to multimodal approaches and the application of artificial intelligence (AI) by machine and deep learning algorithms will help to leverage the full potential of focal therapies for prostate cancer in the upcoming era of precision medicine.

ACHIEVEMENTS

Completion of ongoing randomized trials comparing each minimally invasive therapy approach with established whole-gland procedures is needed before minimally invasive therapies can be implemented into existing treatment guidelines.

PRACTICAL RECOMMENDATIONS

This review article highlights minimally invasive therapies of prostate cancer and the key role of mpMRI for planning and conducting these therapies.