Current status of active surveillance in prostate cancer

Prostate cancer treatment - China's perspective

Prostate cancer (PCa) incidence and mortality have rapidly increased in China. Notably, unique epidemiological characteristics of PCa are found in the Chinese PCa population, including a low but rising incidence and an inferior but improving disease prognosis. Consequently, the current treatment landscape of PCa in China demonstrates distinct features. Establishing a more thorough understanding of the characteristics of Chinese patients may help provide novel insights into potential treatment strategies for PCa patients. Herein, we review the epidemiological status and differences in treatment modalities of Chinese PCa patients. In addition, we discuss the underlying socioeconomic and biological factors that contribute to such diversity and further propose directions for future efforts in optimizing the PCa treatment in China.

Improved COVID-19 ICU admission and mortality outcomes following treatment with statins: a systematic review and meta-analysis

INTRODUCTION

Approximately 1% of the world population has now been infected by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19). With cases still rising and vaccines just beginning to rollout, we are still several months away from seeing reductions in daily case numbers, hospitalisations, and mortality. Therefore, there is a still an urgent need to control the disease spread by repurposing existing therapeutics. Owing to antiviral, anti-inflammatory, immunomodulatory, and cardioprotective actions, statin therapy has been considered as a plausible approach to improve COVID-19 outcomes.

MATERIAL AND METHODS

We carried out a meta-analysis to investigate the effect of statins on 3 COVID-19 outcomes: intensive care unit (ICU) admission, tracheal intubation, and death. We systematically searched the PubMed, Web of Science, Scopus, and ProQuest databases using keywords related to our aims up to November 2, 2020. All published observational studies and randomised clinical trials on COVID-19 and statins were retrieved. Statistical analysis with random effects modelling was performed using STATA16 software.

RESULTS

The final selected studies (n = 24 studies; 32,715 patients) showed significant reductions in ICU admission (OR = 0.78, 95% CI: 0.58-1.06; n = 10; I 2 = 58.5%) and death (OR = 0.70, 95% CI: 0.55-0.88; n = 21; I 2 = 82.5%) outcomes, with no significant effect on tracheal intubation (OR = 0.79; 95% CI: 0.57-1.11; n = 7; I 2= 89.0%). Furthermore, subgroup analysis suggested that death was reduced further by in-hospital application of stains (OR = 0.40, 95% CI: 0.22-0.73, n = 3; I 2 = 82.5%), compared with pre-hospital use (OR = 0.77, 95% CI: 0.60-0.98, n = 18; I 2 = 81.8%).

CONCLUSIONS

These findings call attention to the need for systematic clinical studies to assess both pre- and in-hospital use of statins as a potential means of reducing COVID-19 disease severity, particularly in terms of reduction of ICU admission and total mortality reduction.

Active surveillance in prostate cancer management: where do we stand now?

Prostate cancer (PCa) is the most common cancer in men, with a steadily rising incidence, affecting on average one in six men during their lifetime. The increase in morbidity is related to the increasing overall life expectancy, prostate-specific antigen testing, implementation of new molecular markers for cancer detection and the more frequent application of multiparametric magnetic resonance imaging. There is growing evidence demonstrating that active surveillance (AS) is an alternative to immediate intervention in patients with very low- and low-risk prostate cancer. Ongoing reports from multiple studies have consistently demonstrated a very low rate of metastases and prostate cancer specific mortality in selected cohorts of patients. As a matter of fact, AS has been adopted by many institutions as a safe and effective management strategy. The aim of our review is to summarize the contemporary data on AS in patients affected with PCa with the intention to present the most clinically useful and pertinent AS protocols.

Patients with Biopsy Gleason Score 3 + 4 Are Not Appropriate Candidates for Active Surveillance

OBJECTIVE

The aim of this study was to evaluate the feasibility of including patients with biopsy Gleason score (bGS) 3 + 4 prostate cancer in an active surveillance (AS) protocol.

METHODS

A total of 615 patients underwent a radical prostatectomy and satisfied the following requirements: prostate-specific antigen ≤10 ng/dL, clinical stage T1c or T2a, 2 or fewer positive biopsy cores, and bGS 6 or 3 + 4 prostate cancer. The patients were divided into two groups according to their bGS (bGS 6 group, n =534; bGS 3 + 4 group, n = 81).

RESULTS

The adverse pathological features were significantly higher in the bGS 3 + 4 group (16.7 vs. 49.4%, p< 0.001). Biochemical recurrence (BCR)-free survival was also significantly lower in this group (p < 0.001). In a multivariate analysis, clinical stage (odds ratio [OR] 2.026, p =0.007), maximum percentage of biopsy core involvement (OR 1.015, p = 0.014), and bGS (OR 1.913, p = 0.030) were independent risk factors for adverse pathological features. However, the bGS was the only variable to forecast BCR (hazard ratio 3.567, p < 0.001).

CONCLUSIONS

A bGS 3 + 4 was the leading risk factor for a worse postoperative prognosis. Therefore, patients with a bGS 3 + 4 are not appropriate candidates for AS.

Evidence of a Causal Association Between Cancer and Alzheimer's Disease: a Mendelian Randomization Analysis

While limited observational evidence suggests that cancer survivors have a decreased risk of developing Alzheimer's disease (AD), and vice versa, it is not clear whether this relationship is causal. Using a Mendelian randomization approach that provides evidence of causality, we found that genetically predicted lung cancer (OR 0.91, 95% CI 0.84-0.99, p = 0.019), leukemia (OR 0.98, 95% CI 0.96-0.995, p = 0.012), and breast cancer (OR 0.94, 95% CI 0.89-0.99, p = 0.028) were associated with 9.0%, 2.4%, and 5.9% lower odds of AD, respectively, per 1-unit higher log odds of cancer. When genetic predictors of all cancers were pooled, cancer was associated with 2.5% lower odds of AD (OR 0.98, 95% CI 0.96-0.988, p = 0.00027) per 1-unit higher log odds of cancer. Finally, genetically predicted smoking-related cancers showed a more robust inverse association with AD than non-smoking related cancers (OR 0.95, 95% CI 0.92-0.98, p = 0.0026, vs. OR 0.98, 95% CI 0.97-0.995, p = 0.0091).

A novel predictor of clinical progression in patients on active surveillance for prostate cancer

INTRODUCTION

Active surveillance (AS) is standard of care in low-risk prostate cancer (PCa). This study describes a novel total cancer location (TCLo) density metric and aims to determine its performance in predicting clinical progression (CP) and grade progression (GP).

METHODS

This was a retrospective study of patients on AS after confirmatory biopsy (CBx). We excluded patients with Gleason ≥7 at CBx and <2 years followup. TCLo was the number of locations with positive cores at diagnosis (DBx) and CBx. TCLo density was TCLo/prostate volume (PV). CP was progression to any active treatment while GP occurred if Gleason ≥7 was identified on repeat biopsy or surgical pathology. Independent predictors of time to CP or GP were estimated with Cox regression. Kaplan-Meier analysis compared progression-free survival (PFS) curves between TCLo density groups. Test characteristics of TCLo density were explored with receiver operating characteristic (ROC) curves.

RESULTS

We included 181 patients who had CBx from 2012-2015 and met inclusion criteria. The mean age of patients was 62.58 years (standard deviation [SD] 7.13) and median followup was 60.9 months (interquartile range [IQR] 23.4). A high TCLo density score (>0.05) was independently associated with time to CP (hazard ratio [HR] 4.70; 95% confidence interval [CI] 2.62-8.42; p<0.001) and GP (HR 3.85; 95% CI 1.91-7.73; p<0.001). ROC curves showed TCLo density has greater area under the curve than number of positive cores at CBx in predicting progression.

CONCLUSIONS

TCLo density is able to stratify patients on AS for risk of CP and GP. With further validation, it could be added to the decision-making algorithm in AS for low-risk localized PCa.

Impact of biopsy perineural invasion on the outcomes of patients who underwent radical prostatectomy: a systematic review and meta-analysis

Objectives: To investigate the association between biopsy perineural invasion (PNI) and oncological outcomes of prostate cancer (PCa) after radical prostatectomy (RP).Materials and methods: A systematic literature search was performed using PubMed, EMBASE and Web of Science up to December 2018 to identify the eligible studies that included localized PCa patients who underwent biopsy and subsequently RP as well as follow-up information. Meta-analyses were conducted using available hazard ratios (HRs) of biopsy PNI from both univariate and multivariate analyses.Results: Eighteen studies including 14,855 patients with treatment follow-up information were included in the current systematic review. The rate of biopsy PNI varied between 7.0% and 33.0%. Seven out of the 18 studies that demonstrated biopsy PNI were associated with adverse pathologic features. Thirteen out of the 18 studies showed biopsy PNI correlated significantly with higher rates of biochemical recurrence (BCR)/cancer progression status or worse prognostic outcomes. With pooled data based on four studies with available univariate analysis results and four studies with multivariate analysis, statistically significant associations were found between biopsy PNI and BCR with univariate analysis (HR = 2.05; 95% CI = 1.57-2.68; p < 0.001) and with multivariate analysis (HR = 1.57; 95% CI = 1.28-1.93; p < 0.001).Conclusion: Evidence from the included observational studies indicated that biopsy PNI was not only correlated with adverse pathologic characteristics but also with worse BCR prognosis of local PCa after RP. The status of biopsy PNI could serve as a promising risk-stratification factor to help the decision-making process, considering active surveillance (AS) or further treatment for PCa patients.

Temporary Health Impact of Prostate MRI and Transrectal Prostate Biopsy in Active Surveillance Prostate Cancer Patients

PURPOSE

To assess the temporary health impact of prostate multiparametric MRI (mpMRI) and transrectal prostate biopsy in an active surveillance prostate cancer population.

METHODS

A two-arm institutional review board-approved HIPAA-compliant prospective observational patient-reported outcomes study was performed from November 2017 to July 2018. Inclusion criteria were men with Gleason 6 prostate cancer in active surveillance undergoing either prostate mpMRI or transrectal prostate biopsy. A survey instrument was constructed using validated metrics in consultation with the local patient- and family-centered care organization. Study subjects were recruited at the time of diagnostic testing and completed the instrument by phone 24 to 72 hours after testing. The primary outcome measure was summary testing-related quality of life (summary utility score), derived from the testing morbidities index (TMI) (scale: 0 = death and 1 = perfect health). TMI is stratified into seven domains, with each domain scored from 1 (no health impact) to 5 (extreme health impact). Testing-related quality-of-life measures in the two cohorts were compared with Mann-Whitney U test.

RESULTS

In all, 122 subjects were recruited, and 90% (110 of 122 [MRI 55 of 60, biopsy 55 of 62]) successfully completed the survey instrument. The temporary quality-of-life impact of transrectal biopsy was significantly greater than that of prostate mpMRI (0.82, 95% confidence interval [CI] 0.79-0.85, versus 0.95, 95% CI 0.94-0.97; P < .001). The largest mean domain-level difference was for intraprocedural pain (transrectal biopsy 2.6, 95% CI 2.4-2.8, versus mpMRI 1.3, 95% CI 1.1-1.5; P < .001).

CONCLUSION

Transrectal prostate biopsy has greater temporary health impact (lower testing-related quality-of-life measure) than prostate mpMRI.

Current Progress and Controversies in Prostate Cancer Management

Objective:

The optimal management strategy for prostate cancer (PCa) remains controversial. We performed a systemic review of current progress and controversies regarding the diagnosis and treatment of PCa.

Data Sources:

We searched PubMed for recently published articles up to July 2017 using the following key words: “prostate cancer,” “progress,” “controversy,” “immunotherapy,” and “prevention.”

Study Selection:

Articles were obtained and reviewed to provide a systematic review of the current progress and controversies regarding PCa management.

Results:

The value of serum prostate-specific antigen (PSA) screening remains controversial, but PSA screening is recommended to facilitate the early diagnosis of PCa in high-risk groups. Prostate biopsy via the transrectal or perineal approach has both advantages and disadvantages. There was a significant correlation between testosterone levels and PCa prognosis. The current research is focused on the mechanisms responsible for PCa. Active surveillance has been proposed as a management strategy for low-risk, localized PCa, but there is an urgent need for further clinical studies to establish the criteria for recommending this approach. The main complications of radical resection for PCa are urinary incontinence and erectile dysfunction, though three-dimensional laparoscopic and robot-assisted laparoscopic techniques have obvious advantages over radical surgery. Radiotherapy is also a therapeutic option for PCa, while immunotherapies may alter the prostate tumor microenvironment. Ongoing studies aim to provide guidance on effective sequential and combination strategies. Prevention remains an important strategy for reducing PCa morbidity and mortality.

Conclusions:

The diagnosis, treatment, and prevention of PCa are complex issues, worthy of intensive study. Further studies are needed to improve the management of PCa.

Identification of men with low-risk biopsy-confirmed prostate cancer as candidates for active surveillance

BACKGROUND

A combined clinical cell-cycle risk (CCR) score that incorporates prognostic molecular and clinical information has been recently developed and validated to improve prostate cancer mortality (PCM) risk stratification over clinical features alone. As clinical features are currently used to select men for active surveillance (AS), we developed and validated a CCR score threshold to improve the identification of men with low-risk disease who are appropriate for AS.

METHODS

The score threshold was selected based on the 90th percentile of CCR scores among men who might typically be considered for AS based on NCCN low/favorable-intermediate risk criteria (CCR = 0.8). The threshold was validated using 10-year PCM in an unselected, conservatively managed cohort and in the subset of the same cohort after excluding men with high-risk features. The clinical effect was evaluated in a contemporary clinical cohort.

RESULTS

In the unselected validation cohort, men with CCR scores below the threshold had a predicted mean 10-year PCM of 2.7%, and the threshold significantly dichotomized low- and high-risk disease (P = 1.2 × 10-5). After excluding high-risk men from the validation cohort, men with CCR scores below the threshold had a predicted mean 10-year PCM of 2.3%, and the threshold significantly dichotomized low- and high-risk disease (P = 0.020). There were no prostate cancer-specific deaths in men with CCR scores below the threshold in either analysis. The proportion of men in the clinical testing cohort identified as candidates for AS was substantially higher using the threshold (68.8%) compared to clinicopathologic features alone (42.6%), while mean 10-year predicted PCM risks remained essentially identical (1.9% vs. 2.0%, respectively).

CONCLUSIONS

The CCR score threshold appropriately dichotomized patients into low- and high-risk groups for 10-year PCM, and may enable more appropriate selection of patients for AS.

Integration and Diagnostic Accuracy of 3T Nonendorectal coil Prostate Magnetic Resonance Imaging in the Context of Active Surveillance

OBJECTIVE

To evaluate the integration of 3T nonendorectal coil multiparametric prostate magnetic resonance imaging (mpMRI) at 2 high-volume practices that routinely use mpMRI in the setting of active surveillance.

MATERIALS AND METHODS

This was an institutional review board-approved, Health Insurance Portability and Accountability Act-compliant, and dual-institution retrospective cohort study. Subjects undergoing 3T mpMRI without endorectal coil at either study institution over a 13-month period (August 1, 2015-August 31, 2016) were selected based on predefined criteria: clinical T1/T2 Gleason 6 prostate cancer, prostate-specific antigen <15 ng/mL, ≥40 years old, mpMRI within 2 years of prostate biopsy, and Prostate Imaging Reporting and Data System (PI-RADS) v2 score assigned. Subjects surveilled for Gleason ≥3 + 4 prostate cancer were excluded. The primary outcome was detection of Gleason ≥3 + 4 prostate cancer on magnetic resonance-ultrasound fusion biopsy, standard biopsy, or prostatectomy within 6 months following mpMRI. Positive predictive values (PPVs) were calculated.

RESULTS

A total of 286 subjects (N = 193 from institution 1, N = 93 from institution 2) met the criteria. Most (87% [90 of 104]) with maximum PI-RADS v2 scores of 1-2 did not receive immediate biopsy or treatment and remained on active surveillance. Incidence and PPVs for PI-RADS v2 scores of ≥3 were the following: PI-RADS 3 (n = 57 [20%], PPV 21% [6 of 29]), PI-RADS 4 (n = 96 [34%], PPV 51% [39 of 77]), and PI-RADS 5 (n = 29 [13%], PPV 71% [20 of 28]). No Gleason ≥4 + 3 prostate cancer was identified for PI-RADS v2 scores of 1-3 (0 of 43 with histology). Following mpMRI and subsequent biopsy, 21% (61 of 286) of subjects were removed from active surveillance and underwent definitive therapy.

CONCLUSION

The 3T nonendorectal coil mpMRI has been integrated into the care of patients on active surveillance and effectively stratifies risk of Gleason ≥3 + 4 prostate cancer in this population.

Will 68Ga PSMA-radioligands be the only choice for nuclear medicine in prostate cancer in the near future? A clinical update

Prostate Cancer (PCa) represents the most common malignant tumor in men but according to the European Association of Urology (EAU) guidelines, a mass screening for PCa diagnosis should not be performed due to over-diagnosis and over-treatment related problems. An early clinical diagnosis is possible, mainly based on digital rectal examination and Prostatic Specific Agent (PSA) testing. However, the only mandatory test to define the presence of PCa is ultrasound guided-biopsy, obtained on multiple samples, which has also a high prognostic value. In this context, diagnostic imaging plays an important role as confirmed by EAU that in a 2016 update of their guidelines on PCa stated the importance of Positron Emission Tomography (PET) with ¹¹C- or ¹⁸F-choline combined with computed tomography (CT) to identify local relapse, lymph node involvement and metastatic spread at all stages. Consequently, in 2017, the European Association of Nuclear Medicine (EANM) together with the Society of Nuclear Medicine and Molecular Imaging (SNMMI) published new guidelines for ⁶⁸Ga-Prostate Specific Membrane Antigen (PSMA) PET/CT to help physicians in the recommendation, execution and interpretation of PET/CT scans in patients with PCa. Thus, the aim of this 'evidence paper' is to define the current diagnostic algorithm in PCa in order to increase the general level of confidence in approaching such a crucial topic.

Patient and provider experiences with active surveillance: A scoping review

Objective

Active surveillance (AS) represents a fundamental shift in managing select cancer patients that initiates treatment only upon disease progression to avoid overtreatment. Given uncertain outcomes, patient engagement could support decision-making about AS. Little is known about how to optimize patient engagement for AS decision-making. This scoping review aimed to characterize research on patient and provider communication about AS, and associated determinants and outcomes.

Methods

MEDLINE, EMBASE, CINAHL, and The Cochrane Library were searched from 2006 to October 2016. English language studies that evaluated cancer patient or provider AS views, experiences or behavioural interventions were eligible. Screening and data extraction were done in duplicate. Summary statistics were used to describe study characteristics and findings.

Results

A total of 2,078 studies were identified, 1,587 were unique, and 1,243 were excluded based on titles/abstracts. Among 344 full-text articles, 73 studies were eligible: 2 ductal carcinoma in situ (DCIS), 4 chronic lymphocytic leukemia (CLL), 6 renal cell carcinoma (RCC) and 61 prostate cancer. The most influential determinant of initiating AS was physician recommendation. Others included higher socioeconomic status, smaller tumor size, comorbid disease, older age, and preference to avoid adverse treatment effects. AS patients desired more information about AS and reassurance about future treatment options, involvement in decision-making and assessment of illness uncertainty and supportive care needs during follow-up. Only three studies of prostate cancer evaluated interventions to improve AS communication or experience.

Conclusions

This study revealed a paucity of research on AS communication for DCIS, RCC and CLL, but generated insight on how to optimize AS discussions in the context of routine care or clinical trials from research on AS for prostate cancer. Further research is needed on AS for patients with DCIS, RCC and CLL, and to evaluate interventions aimed at patients and/or providers to improve AS communication, experience and associated outcomes.

Favorable Gleason 3 + 4 Prostate Cancer Shows Comparable Outcomes With Gleason 3 + 3 Prostate Cancer: Implications for the Expansion of Selection Criteria for Active Surveillance

BACKGROUND

To investigate the feasibility of active surveillance (AS) in biopsy Gleason score (GS) 3 + 4 prostate cancer (PCa), we compared the outcomes of biopsy GS 3 + 3 and 3 + 4 PCa after radical prostatectomy.

PATIENTS AND METHODS

We analyzed the data of 1491 patients undergoing radical prostatectomy for biopsy GS 3 + 3 or 3 + 4 PCa who fulfilled the low-risk criteria of the National Comprehensive Cancer Network guidelines regardless of GS. The favorable GS 3 + 4 group was defined as having core involvement ≤ 50%, prostate-specific antigen density ≤ 0.2 ng/mL/cm³, and number of positive cores ≤ 2 (maximal 1 core of GS 3 + 4).

RESULTS

The GS 3 + 4 group showed significantly worse pathologic outcomes, including pathologic GS, pathologic stage, and seminal vesicle invasion rate (all P < .001), as well as worse biochemical recurrence-free survival (P < .001) than the GS 3 + 3 group. However, the favorable GS 3 + 4 subgroup showed no significant differences in the pathologic outcomes (all P > .05) and in biochemical recurrence-free survival (P = .817) compared to the GS 3 + 3 group.

CONCLUSION

Despite the application of low-risk criteria, GS 3 + 4 PCa patients showed significantly worse outcomes than GS 3 + 3 patients. However, favorable GS 3 + 4 patients showed comparable clinicopathologic outcomes with GS 3 + 3 patients, suggesting possible expansion of AS for the favorable GS 3 + 4 group.

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.

Active surveillance for low-risk prostate cancer in Austria: the online registry of the Qualitätspartnerschaft Urologie (QuapU)

BACKGROUND

Active surveillance (AS) is a well-recognized strategy to reduce the risk of overtreatment in men with low-risk prostate cancer. No data on this approach are available from Austria.

METHODS

The Qualitätspartnerschaft Urologie (QuapU) developed an online database for patients managed with AS in Austria. Principal inclusion/exclusion criteria corresponded to those of the S3 prostate cancer guideline of German urologists: prostate-specific antigen (PSA) <10 ng/ml, Gleason score <7 (maximum 20% of biopsies being positive). Control visits were scheduled at 3‑month intervals, control biopsies were scheduled at 12 and 36 months.

RESULTS

To date 131 patients have been entered into this data base. Mean patient age is 64 years, 6% were younger than 50 years, two thirds of patients were aged 50-70 years and 25% were older than 70 years. Mean PSA value was 5.9 ng/ml (PSA 0-4 ng/ml: 15%; PSA >4-10 ng/ml: 85%). The prostate volume averaged 39 ml. The mean time under AS was 17.5 months (<12 months: 60%; >12 months: 40%). The AS adherence at 12 months was 85% and at 24 months 76%. To date, a total of 23 patients (17.6%) stopped AS. The most frequent reasons for discontinuing AS were patient wish for active treatment (43.5%) and PSA progression (30.4%). A histological progression was rarely seen (6.1%) and the control biopsy rate was low (19.8%).

CONCLUSION

This study is the first description of AS in Austria and documents the feasibility of an online registry for AS. The data confirm the international experience with this approach with acceptable adherence rates.

Are magnetic resonance imaging undetectable prostate tumours clinically significant? Results of histopathological analyses

OBJECTIVE

To investigate whether tumours at threshold values for detection on magnetic resonance imaging (MRI) represent clinically significant tumours or not, and therefore the utility of MRI in active surveillance (AS) protocols.

PATIENTS AND METHODS

A retrospective analysis of a single institution database was performed after Institutional Review Board approval. Between 2010 and 2013, 1633 patients underwent robot-assisted laparoscopic prostatectomy (RALP) at a single institution by a single surgeon. Of these, 1361 had complete clinical data and were included in analysis. Multivariate logistic regression was used to assess histopathological grade compared to tumour size whilst controlling for biopsy Gleason score, prostate-specific antigen level, body mass index, race, and age.

RESULTS

Of 120 tumours <5 mm in size, four were Gleason score 4 + 3. Of 276 tumours of 5-10 mm, 22 (8.1%) were Gleason score 4 + 3 and one (0.2%) was Gleason score 8. On multivariate regression analyses, tumours of <5 mm were much less likely to be high grade (Gleason score >3 + 4) at RALP compared to larger tumours (3.3% vs 25.1%, P < 0.001), or Gleason score ⩾8 (0.0% vs 7.6%, P < 0.001). Size was further shown to significantly correlate with grade on multivariate regression (P < 0.001).

CONCLUSIONS

Prostate tumours below the detection threshold for MRI (5 mm) most probably represent clinically insignificant tumours, which alone would not necessitate leaving AS in favour of more aggressive therapy. These findings point to a possible role of MRI in modern AS protocols.