Active surveillance for favorable-risk prostate cancer: who, how and why?

IVIM Parameters on MRI Could Predict ISUP Risk Groups of Prostate Cancers on Radical Prostatectomy

Purpose

To elucidate the usefulness of intravoxel incoherent motion (IVIM)/apparent diffusion coefficient (ADC) parameters in preoperative risk stratification using International Society of Urological Pathology (ISUP) grades.

Materials and Methods

Forty-five prostate cancer (PCa) patients undergoing radical prostatectomy (RP) after prostate multiparametric magnetic resonance imaging (mpMRI) were included. The ISUP grades were categorized into low-risk (I-II) and high-risk (III-V) groups, and the concordance between the preoperative and postoperative grades was analyzed. The largest region of interest (ROI) of the dominant tumor on each IVIM/ADC image was delineated to obtain its histogram values (i.e., minimum, mean, and kurtosis) of diffusivity (D), pseudodiffusivity (D*), perfusion fraction (PF), and ADC. Multivariable logistic regression analysis of the IVIM/ADC parameters without and with preoperative ISUP grades were performed to identify predictors for the postoperative high-risk group.

Results

Thirty-two (71.1%) of 45 patients had concordant preoperative and postoperative ISUP grades. D_mean, D*_kurtosis, PF_kurtosis, ADC_min, and ADC_mean were significantly associated with the postoperative ISUP risk group (all p < 0.05). D_mean and D*_kurtosis (model I, both p < 0.05) could predict the postoperative ISUP high-risk group with an area under the curve (AUC) of 0.842 and a 95% confidence interval (CI) of 0.726-0.958. The addition of D*_kurtosis to the preoperative ISUP grade (model II) may enhance prediction performance, with an AUC of 0.907 (95% CI 0.822-0.992).

Conclusions

The postoperative ISUP risk group could be predicted by D_mean and D*_kurtosis from mpMRI, especially D*_kurtosis. Obtaining the biexponential IVIM parameters is important for better risk stratification for PCa.

MRI guided focal HDR brachytherapy for localized prostate cancer: Toxicity, biochemical outcome and quality of life

PURPOSE

To describe toxicity, biochemical outcome and quality of life after MRI guided focal high dose rate brachytherapy (HDR-BT) in a single fraction of 19 Gy for localized prostate cancer.

MATERIALS AND METHODS

Between May 2013 and April 2016, 30 patients were treated by MRI-guided focal HDR-BT. Patients with visible tumour on MRI were included. All patients were ≥65 years, T-stage <T3, Gleason ≤7, PSA <10 ng/mL and IPSS <15. Focal irradiation was delivered in a single fraction of 19 Gy to the D95 of the clinical target volume. Toxicity was reported using the Common Terminology Criteria for Adverse Events version 4. Biochemical failure was defined according to the Phoenix criteria and quality of life was measured using validated questionnaires.

RESULTS

Median follow up was 24 months. One patient developed a grade 2 and 3 GU toxicity after treatment. In the other 29 patients, no grade 2 or higher perioperative complications occurred. Five patients developed a biochemical recurrence. For all measured time points, there was no statistically significant deterioration in quality of life.

CONCLUSION

Focal MRI guided HDR-BT confers low toxicity rates and maintains quality of life. Biochemical recurrence is rather high, 5 patients developed a biochemical recurrence according to the Phoenix definition. Longer evaluation of these patients is necessary and caution is warranted before implementing focal HDR-BT in patients with localized prostate cancer.

Urinary DNA Methylation Biomarkers for Noninvasive Prediction of Aggressive Disease in Patients with Prostate Cancer on Active Surveillance

PURPOSE

Patients with prostate cancer on active surveillance are monitored by repeat prostate specific antigen measurements, digital rectal examinations and prostate biopsies. A subset of patients on active surveillance will later reclassify with disease progression, prompting definitive treatment. To minimize the risk of under treating such patients on active surveillance minimally invasive tests are urgently needed incorporating biomarkers to identify patients who will reclassify.

MATERIALS AND METHODS

We assessed post-digital rectal examination urine samples of patients on active surveillance for select DNA methylation biomarkers that were previously investigated in radical prostatectomy specimens and shown to correlate with an increasing risk of prostate cancer. Post-digital rectal examination urine samples were prospectively collected from 153 men on active surveillance who were diagnosed with Gleason score 6 disease. Urinary sediment DNA was analyzed for 8 DNA methylation biomarkers by multiplex MethyLight assay. Correlative analyses were performed on gene methylation and clinicopathological variables to test the ability to predict patient risk reclassification.

RESULTS

Using backward logistic regression a 4-gene methylation classifier panel (APC, CRIP3, GSTP1 and HOXD8) was identified. The classifier panel was able to predict patient reclassification (OR 2.559, 95% CI 1.257-5.212). We observed this panel to be an independent and superior predictor compared to current clinical predictors such as prostate specific antigen at diagnosis or the percent of tumor positive cores in the initial biopsy.

CONCLUSION

We report that a urine based classifier panel of 4 methylation biomarkers predicts disease progression in patients on active surveillance. Once validated in independent active surveillance cohorts, these promising biomarkers may help establish a less invasive method to monitor patients on active surveillance programs.

Can we negotiate with a tumor?

Recent progress in deciphering the molecular portraits of tumors promises an era of more personalized drug choices. However, current protocols still follow standard fixed-time schedules, which is not entirely coherent with the common observation that most tumors do not grow continuously. This unpredictability of the increases in tumor mass is not necessarily an obstacle to therapeutic efficiency, particularly if tumor dynamics could be exploited. We propose a model of tumor mass evolution as the integrated result of the dynamics of two linked complex systems, tumor cell population and tumor microenvironment, and show the practical relevance of this nonlinear approach.

External validation of a Brazilian predictive nomogram for pathologic outcomes following radical prostatectomy in tertiary teaching institutions: the USP nomograms

PURPOSES

(a) To externally validate the Crippa and colleagues' nomograms combining PSA, percentage of positive biopsy cores (PPBC) and biopsy Gleason score to predict organ-confined disease (OCD) in a contemporary sample of patients treated at a tertiary teaching institution. (b) To adjust such variables, resulting in predictive nomograms for OCD and seminal vesicle invasion (SVI): the USP nomograms.

MATERIALS AND METHODS

The accuracy of Crippa and colleagues' nomograms for OCD prediction was examined in 1002 men submitted to radical prostatectomy between 2005 and 2010 at the University of São Paulo (USP). ROC-derived area under the curve (AUC) and Brier scores were used to assess the discriminant properties of nomograms for OCD. Nomograms performance was explored graphically with LOESS smoothing plots. Furthermore, univariate analysis and logistic regression models targeted OCD and SVI. Variables consisted of PSA, PPBC, biopsy Gleason score and clinical stage. The resulted predictive nomograms for OCD and SVI were internally validated with bootstrapping and the same abovementioned procedures.

RESULTS

Crippa and colleagues' nomograms for OCD showed ROC AUC = 0.68 (CI: 0.65-0.70), Brier score = 0.17 and overestimation in LOESS plots. USP nomograms for OCDand SVI showed ROC AUC of 0.73 (CI: 0.70-0.76) and 0.77 (CI: 0.73-0.79), respectively, and Brier scores of 0.16 and 0.08, respectively. The LOESS plots showed excellent calibration for OCD and underestimation for SVI.

CONCLUSIONS

Crippa and colleagues' nomograms showed moderate discrimination and considerable OCD overestimation. USP nomograms showed good discrimination for OCD and SVI, as well as excellent calibration for OCD and SVI underestimation.

Early experience with active surveillance in low-risk prostate cancer treated

Purpose

This study was conducted to describe our early experience with active surveillance (AS).

Materials and Methods

Between January 2008 and December 2012, 35 patients were treated with AS. Selection criteria included the following: Gleason score ≤6 with single positive core, clinical stage ≤T1c, prostate-specific antigen (PSA) ≤10 ng/mL, and unremarkable imaging results. On patient follow-up, we regularly measured PSA (every 3-6 months) and performed prostate biopsies (after 1 and 3 years).

Results

In the first year of follow-up, prostate biopsies were performed in 25 patients (13 patients, negative for cancer; 7 patients, Gleason score of 6 without progression; 5 patients, progression, treated with radical prostatectomy [RP]). In the third year of follow-up, prostate biopsies were performed in five patients (two patients, negative for cancer; one patient, Gleason score of 6 without progression; two patients, progression, treated with RP). Seven patients discontinued AS because of increased anxiety, and three patients were lost to follow-up. Overall, seven patients (28%) who experienced progression had a mean PSA doubling time (DT) of 7.54 years. Six patients had a PSA DT of more than 3 years, whereas one had a PSA DT of less than 3 years. This study was limited by its small sample size and short follow-up period.

Conclusions

PSA kinetics did not correlate with progression, which suggests that regular biopsies should still be performed. AS is an available treatment option for patients with a low risk of prostate cancer but should only be used in carefully selected patients.

The current status of active surveillance for prostate cancer

The occurrence of low-risk, localized prostate cancer (PCa) has increased in the prostate-specific antigen era. A significant amount of low-risk PCas progress slowly and may not impact patient survival. Thus, these patients may be subjected to unnecessary interventions that result in physical and psychological complications. The active surveillance (AS) protocol has been used over the few past decades. It was designed so that patients with low-risk PCa can be monitored for a period of time, during which they are free from complication of interventions, and can be treated with curative intention on evidence of disease progression. Institutions have developed different selection criteria and follow-up schedules for suitable patients with PCa. Recently, long-term data have emerged suggesting that AS is a reasonable option for appropriately selected patients with low-risk PCa who have a life expectancy of < 10 years. Subsequently, the AS protocol has been recognized by various guidelines as part of the treatment strategy for PCa. However, the challenges that remain for AS are the risk of under-staging of PCa and the low uptake and high attrition rate of AS, and questions remain regarding its long-term efficacy. Recent advances in AS for PCa, such as better imaging modality, combining AS with limited local therapy, as well as the role of AS in association with chemoprevention, are discussed.

Watchful waiting and quality of life among prostate cancer survivors in the Physicians' Health Study

PURPOSE

We examined patient reported outcomes among patients with prostate cancer treated with watchful waiting in a nationwide cohort.

MATERIALS AND METHODS

We collected treatment information and patient reported outcomes from 1,230 patients with prostate cancer diagnosed with T1-T2 prostate cancer in the Physicians' Health Study, of whom 125 were initially treated with watchful waiting. Cox proportional hazards regression was used to identify predictors of treatment initiation among patients on watchful waiting. Logistic regression was used to calculate the OR and 95% CI to assess disease targeted quality of life by initial treatment or watchful waiting.

RESULTS

At a mean 7.3-year followup 41% of patients on watchful waiting remained free of treatment while 34% had received radiotherapy or brachytherapy, 16% had received primary hormonal therapy and 10% had undergone prostatectomy. Younger age, higher clinical stage, higher Gleason score and higher prostate specific antigen at diagnosis predicted progression to treatment. Watchful waiting compared to immediate treatment was associated with less urinary incontinence (3.5% vs 10%) and impotence (68% vs 78%) but more common obstructive urinary symptoms (22% vs 13%) on univariate analysis (each p <0.05). Incontinence and impotence differences remained significant after adjusting for age, comorbidity and time after cancer diagnosis. Quality of life outcomes in men who underwent delayed treatment after initially waiting were not worse than in men who underwent immediate treatment.

CONCLUSIONS

Findings suggest quality of life benefits after watchful waiting in select patients with early stage prostate cancer compared to men treated immediately after diagnosis. Younger age and greater cancer severity at diagnosis predicted progression to treatment.

Active surveillance for low-risk prostate cancer: an update

Active surveillance is now an accepted management strategy for men with low-risk localized prostate cancer, in recognition of the knowledge that the majority of men with such cancers are likely to die from other causes. The most obvious benefit of active surveillance is the reduction of morbidity associated with surgery by delaying or avoiding radical gland therapy. Other advantages include lower overall costs to the health-care system and potentially a better quality of life. These advantages should be balanced against the risks of delayed therapy, the most considerable of which being development of more-aggressive disease. Appropriate selection criteria and the definition of triggers for intervention with radical therapy are critical components of an active surveillance protocol. The ability to accurately identify and cure the men whose cancers will progress using clinical, biopsy and imaging data is yet to be resolved, as is the psychological burden of living with an untreated cancer. The benefit of 5α-reductase inhibitors as secondary chemoprevention in men on active surveillance is a new avenue of research. Focal therapy, which has the similar aim of reducing morbidity while maintaining oncological control, is an emerging competitor for active surveillance. Nevertheless, active surveillance is an appealing management option for selected men with prostate cancer.

Active surveillance for favorable-risk prostate cancer: a short review

Active surveillance is becoming a more widely accepted management strategy in men with low-risk localized prostate cancer. This is in recognition of the knowledge that most men with such cancer are likely to die from other causes. The obvious benefits of active surveillance are reduced morbidity by delaying or avoiding radical gland therapy. These advantages should be balanced against appropriate selection criteria and triggers for moving to radical therapy while on active surveillance. The optimal method by which to identify the small number of men who will progress by use of clinical, biopsy, and imaging data is yet to be defined. Nevertheless, active surveillance is an appealing management option in selected men with prostate cancer and represents a solution to the significant problem of the overdiagnosis of clinically insignificant disease that accompanies prostate-specific antigen (PSA) screening.

Fractal analysis of two-dimensional vascularity in primary prostate cancer and surrounding non-tumoral parenchyma

Prostate cancer is the fifth most frequent cancer in the world. However, none of the actual prognostic factors provide a valid index for predicting patient outcome. Here, we evaluate the two-dimensional vascularity in primary prostate tumors and surrounding non-tumoral parenchyma by means of fractal geometry, and assess any correlations between the results and some clinical and pathological parameters of prostate carcinoma. Prostate sections from 27 carcinoma patients were treated with CD34 antibodies. Two >10mm(2) areas of tumoral and surrounding non-tumoral parenchyma were digitized using an image analysis system that automatically quantified the fractal dimension of the vascular surface. Data were correlated with patient's age, PSA level, clinical and pathological stage, Gleason score, tumor volume, vascular invasion, surgical margins, and biochemical relapse. Two groups of patients were distinguished on the basis of whether the fractal dimension of their tumoral vascular surface was higher (group 1) or lower (group 2) than that of the surrounding non-tumoral parenchyma. Statistically significant between-group differences were found in terms of serum PSA levels (p=0.0061), tumor volume (p=0.0017), and biochemical relapse (p=0.031). The patients in group 2 had a poorer outcome. Our findings suggest a group of prostate cancer patients with a poor outcome, and the vascular surface fractal dimension as a helpful geometrical index in clinical practice.

A high cannabinoid CB(1) receptor immunoreactivity is associated with disease severity and outcome in prostate cancer

In the light of findings indicating that cannabinoids can affect the proliferation of a number of cancer cell types and that cannabinoid receptor expression is higher in prostate cancer cell lines than in non-malignant cells, we investigated whether the level of cannabinoid 1 receptor immunoreactivity (CB(1)IR) in prostate cancer tissues is associated with disease severity and outcome. Formalin-fixed paraffin-embedded non-malignant and tumour tissue samples from patients who were diagnosed with prostate cancer at a transurethral resection for voiding problems were used. CB(1)IR, which was scored in a total of 399 cases, was associated with the epithelial cell membranes, with little staining in the stroma. Patients with a tumour CB(1)IR score greater or equal to the median (2) had a significantly higher proportion of Gleason scores 8-10, metastases at diagnosis, tumour size and rate of cell proliferation at diagnosis than patients with a score<2. For 269 cases, tumour CB(1)IR was measured for patients who only received palliative therapy at the end stages of the disease, allowing the influence of CB(1)IR upon the disease outcome to be determined. Receiver operating characteristic (ROC) curves showed an area under the curve of 0.67 (95% confidence limits 0.59-0.74) for CB(1)IR in the tumour. CB(1)IR in non-malignant tissue was not associated with disease outcome. A tumour CB(1)IR score >or=2 was associated with a significantly lower disease specific survival. A Cox proportional hazards regression indicated that the tumour CB(1)IR score and the Gleason score were independent prognostic variables. It is concluded that a high tumour CB(1)IR score is associated with prostate cancer severity and outcome.

[Insignificant prostate cancer. Analysis our series]

The objective of this study is to analyse the specimen of radical prostatectomy of patients who had, prior to the surgery insignificant prostate cancer biopsies. The end point is demonstrate the possibility of an active surveillance as a therapeutic option for prostate cancer in selected is the possibility of an active surveillance as therapeutic for the prostate cancer, in selected individuals if we are able to find diagnostic algorisms to predict the real insignificant tumours. The selected group of patients for the study has a PSA less or equal 10, one positive core of prostatic transrectal ultrasound biopsy with a Gleason score less than 7. This group of patients is considerate as having a potential insignificant tumour. We will consider prostatectomy's specimens and the Gleason sore is less than 7 and the tumoral volume is les or equal to 5%. Of 394 patients with prostate cancer and homogeneous criterias for our study, we have selected 53 patients according to the criteria of insignificant tumour in the biopsy. Our results showed that only 22 of 53 (41.5%) patients were identified as having an insignificant prostate cancer in the RP specimens. Moreover 92.2% of this tumours were organ-confined. In conclusion we are able to say that tumours of low-risk and low tumoral volume in the biopsy, do not correlate always to insignificant tumours in PR specimens, but we have observed that the majority are organ-confined tumours. Finally, the diagnostic's algorisms dies not to predict tumours that may safely treated with active monitoring.

[Active surveillance for prostate cancer]

Active surveillance is a valuable treatment option in patients with newly diagnosed low-risk prostate cancer. Studies considering a watchful waiting approach showed favourable cancer-specific survival rates in such patients and it is assumed that patients benefit from a definitive therapy if life expectancy exceeds 10-15 years. Therefore active surveillance is especially valuable in older men and in patients with an elevated comorbidity profile. Precise identification of histologically and clinically insignificant prostate cancers is still not possible today. Active surveillance includes regular PSA measurements combined with follow-up biopsies; however, no standardized protocol exists so far. Histological progression in the follow-up biopsy and PSA elevation are the most important criteria for initiating definitive therapy. Today only a minority of low-risk patients join an active surveillance protocol and a substantial proportion of these men leave such a protocol early without evidence of progression. The psychological burden of living with an untreated cancer seems to be responsible for this. Active surveillance has the potential to lead to undertreatment as there is some evidence that prolonged treatment delay might adversely affect outcome of definitive therapy.