The independent value of tumour volume in a contemporary cohort of men treated with radical prostatectomy for clinically localized disease

How reliable is the high-volume definition in prostate cancer patients: the potential game-changing role of PSMA

PURPOSE

To evaluate whether metabolic and volumetric data from 68 Ga-PSMA PET/CT performed during staging of de-novo high-volume mCSPC patients who received docetaxel could be used to predict survival.

METHODS

Forty-two de-novo high-volume mCSPC patients, who received ADT + Docetaxel and underwent 68 Ga-PSMA PET/CT for staging, were included in the study. The association between patients' pathological data, all PSA measurements, treatments they received, the data obtained from 68 Ga-PSMA PET/CT and progression-free and overall survival were examined.

RESULTS

In the multivariate analysis, PSMA-TV (primary) and PSMA-TV (WB) variables were shown to be independent negative predictors of overall survival. For the threshold value of 19.91 cm 3 obtained for PSMA-TV (primary), HR was calculated as 6.31, the 95% confidence interval (CI): 1.01-39.18, P = 0.048. For the threshold value of 1226.5 cm 3 obtained for PSMA-TV (WB) variable, HR was calculated as 58.62, the 95% CI: 2.55-1344.43, P = 0.011. In our study, SUVmax (WB) variable was found to be an independent and negative predictor of progression-free survival. For the determined threshold value of 17.74, HR was calculated as 16.24, 95% CI: 1.18-22.76, P = 0.037.

CONCLUSION

Metabolic and volumetric data obtained from 68 Ga-PSMA PET/CT can be used to predict survival in de-novo high-volume mCSPC. Our results show that in ADT + Docetaxel receiving patients, a subgroup with higher PSMA-TV (WB) values have a significantly worse prognosis. This situation suggests that the high-volume disease definition in the literature may be insufficient for this group, and that 68 Ga-PSMA PET/CT can play an essential role in demonstrating the heterogeneity within the group.

Clinicopathological Significances of Positive Surgical Resection Margin after Radical Prostatectomy for Prostatic Cancers: A Meta-Analysis

Background and Objectives: This study aims to elucidate the positive rate and the clinicopathological significance of surgical margin after radical prostatectomy (RP) through a meta-analysis. Materials and Methods: This meta-analysis finally used 59 studies, including the information about the positive surgical margin (PSM) and those clinicopathological significances after RP. The subgroup analysis for the estimated rates of PSM was evaluated based on types of surgery, grade groups, and pathological tumor (pT) stages. We compared the clinicopathological correlations between positive and negative surgical margins (NSM). Results: The estimated PSM rate was 25.3% after RP (95% confidence interval [CI] 21.9-29.0%). The PSM rates were 26.0% (95% CI 21.5-31.1%) 28.0% (95% CI 20.2-37.5%) in robot-assisted RP and nerve-sparing RP, respectively. The PSM rate was significantly higher in high-grade groups than in low-grade groups. In addition, the higher pT stage subgroup had a high PSM rate compared to the lower pT stage subgroups. Patients with PSM showed significantly high PSA levels, frequent lymphovascular invasion, lymph node metastasis, and extraprostatic extension. Biochemical recurrences (BCRs) were 28.5% (95% CI 21.4-36.9%) and 11.8% (95% CI 8.1-16.9%) in PSM and NSM subgroups, respectively. Patients with PSM showed worse BCR-free survival than those with NSM (hazard ratio 2.368, 95% CI 2.043-2.744%). Conclusions: Our results showed that PSM was significantly correlated with worse clinicopathological characteristics and biochemical recurrence-free survival. Among the results in preoperative evaluations, grade group and tumor stage are useful for the prediction of PSM.

Is tumour volume an independent predictor of outcome after radical prostatectomy for high-risk prostate cancer?

BACKGROUND

Preoperative PSA, ISUP grade group (GG), prostate examination and multiparametric MRI (mpMRI) form the basis of prostate cancer staging. Unlike other solid organ tumours, tumour volume (TV) is not routinely used aside from crude estimates such as maximum cancer core length. The aim of this study is to assess the role of TV as a marker for oncological outcomes in high-risk non-metastatic prostate cancer.

METHODS

A prospectively maintained database of patients undergoing minimally invasive (laparoscopic or robot-assisted laparoscopic) radical prostatectomy at a UK centre between 2007 and 2019 were analysed. A total of 251 patients with NCCN high or very high-risk prostate cancer were identified. Primary outcome measure was time to biochemical recurrence (BCR) and the secondary outcome was time to treatment failure (TTF). TV was measured on the pathological specimen using the stacking method. Multivariable cox regression analysis was used to identify factors predicting BCR and TFF. TV as a predictor of BCR and TFF was further analysed through time-dependent receiver operating characteristic (ROC) curves. Kaplan-Meier survival estimates were used to evaluate TV cut-off scores.

RESULTS

Median follow up was 4.50 years. Four factors were associated with BCR and TFF on multivariable analysis (TV, pathological GG, pathological T stage, positive margin >3 mm). Area under the Curve (AUC) for TV as a predictor of BCR and TTF at 5 years was 0.71 and 0.75, respectively. Including all 4 variables in the model increased AUC to 0.84 and 0.85 for BCR and TFF. A 2.50 cm TV cut off demonstrated a significance difference in time to BCR, p < 0.001.

CONCLUSIONS

Pathological tumour volume is an independent predictor of oncological outcomes in high risk prostate cancer but does not add significant prognostic value when combined with established variables. However, the option of accurate TV measurement on mpMRI raises the possibility of using TV as useful marker for preoperative risk stratification.

How accurately can multiparametric magnetic resonance imaging measure the tumour volume of a prostate cancer? Results of a systematic review

The tumour volume of a cancer within the prostate gland is commonly measured with multiparametric MRI. The measurement has a role in many clinical scenarios including focal therapy, but the accuracy of it has never been systematically reviewed. We included articles if they compared tumour volume measurements obtained by mpMRI with a reference volume measurement obtained after radical prostatectomy. Correlation and concordance statistics were summarised. A simple accuracy score was derived by dividing the given mean or median mpMRI volume by the histopathological reference volume. Factors affecting the accuracy were noted. Scores for potential bias and quality were calculated for each article. A total of 18 articles describing 1438 patients were identified. Nine articles gave Pearson's correlation scores, with a median value of 0.75 but the range was wide (0.42-0.97). A total of 11 articles reported mean values for volume while 9 reported median values. For all 18 articles, the mean or median values for MRI volumes were lower than the corresponding reference values suggesting consistent underestimation. For articles reporting mean and median values for volume, the median accuracy scores were 0.83 and 0.80, respectively. The accuracy was higher for tumours of greater volume, higher grade and when an endorectal coil was used. Accuracy did not seem to improve over time, with a 3 Tesla magnet or by applying a shrinkage factor to the reference measurement. Most studies showed evidence of at least moderate bias, and their quality was highly variable, but neither of these appeared to affect accuracy.

Tumor Volume and Clinical Failure in High-Risk Prostate Cancer Patients Treated With Radical Prostatectomy

INTRODUCTION

To identify the most significant cut-off of tumor volume (TV) for prediction of clinical failure (CF) among high-risk prostate cancer (hPCa) patients.

METHODS

Within a multi-institutional cohort, 262 patients treated with radical prostatectomy (RP) for hPCa were identified. CF was defined as local recurrence or distant metastases. A time dependent ROC curve was used to evaluate the area under the curve (AUC) using TV as single marker to predict clinical failure at 10 years. We searched for the TV cut off value with the highest combined sensitivity and specificity predicting CF. Three multivariable Cox regression analyses (MVA) tested the predictors of CF after RP. Predictors of the model 1 were pre-operative PSA, pathologic stage (PT), pathologic Gleason sum (GS), surgical margin status, and lymph node invasion. Predictors of the models 2 and 3 were the same of model 1 plus TV as a continuous or dichotomous variable using the defined cutoff, respectively. Validation (leave-one-out-cross-validation-LOOCV) of each model was performed.

RESULTS

Overall, 46 (17.6%) patients experienced CF. The TV value was 6.29 ml. In MVA of models 2 and 3, PT and GS remained independent predictors of CF. Moreover, in model 2 TV (HR:1.07,) and in model 3 TV >6.29 ml (HR:2.99,) were independently associated with CF. In LOOCV, the C-index of models 1-3 were 65.53%, 71.75%, and 70.26%, respectively.

CONCLUSIONS

TV is an independent predictor of CF in hPCa patients. Patients with a TV exceeding the cut-off of 6.29 ml are more likely to develop CF. Prostate 77:3-9, 2017. © 2016 Wiley Periodicals, Inc.

Effect of serum testosterone and percent tumor volume on extra-prostatic extension and biochemical recurrence after laparoscopic radical prostatectomy

Several studies have revealed that the preoperative serum testosterone and percent tumor volume (PTV) predict extra-prostatic extension (EPE) and biochemical recurrence (BCR) after radical prostatectomy. This study investigated the prognostic significance of serum testosterone and PTV in relation to EPE and BCR after laparoscopic radical prostatectomy (LRP). We reviewed 520 patients who underwent LRP between 2004 and 2012. PTV was determined as the sum of all visually estimated tumor foci in every section. BCR was defined as two consecutive increases in the postoperative prostate-specific antigen (PSA) >0.2 ng ml-1 . The threshold for serum total testosterone was 3.0 ng ml-1 . Multivariate logistic regression was used to define the effect of variables on the risk of EPE and BCR. A low serum testosterone (<3.0 ng ml-1 ) was associated with a high serum PSA, Gleason score, positive core percentage of the prostate biopsy, PTV, and all pathological variables. On multivariate analysis, similar to previous studies, the serum PSA, biopsy positive core percentage, Gleason score, and pathological variables predicted EPE and BCR. In addition, low serum testosterone (<3.0 ng ml-1 , adjusted OR, 8.52; 95% CI, 5.04-14.4, P= 0.001) predicted EPE and PTV (adjusted OR, 1.02; 95% CI, 1.01-1.05, P= 0.046) predicted BCR. In addition to previous predictors of EPE and BCR, low serum testosterone and PTV are valuable predictors of EPE and BCR after LRP.

Efficacy of primary tumour volume as a predictor of survival compared with size alone in pancreatic ductal adenocarcinoma

Tumour size (TSize) predicts outcome in pancreatic ductal adenocarcinoma (PDAC), but little is known regarding three-dimensional tumour volume (TVol) associations. We hypothesised that TVol would more accurately predict outcome following pancreatoduodenectomy (PD) for PDAC. Clinicopathological and outcome data was reviewed for all PDs performed in the Royal North Shore Hospital (St. Leonards, NSW, Australia), between April 2004 and November 2010, in patients whose three tumour dimensions were recorded (n=103). TVol was quantified using the ellipsoidal volume formula, 4/3π(r1×r2×r3), and was correlated with clinicopathological indices/outcome. Over a median follow-up time of 20.5 months, TVol failed to significantly predict post-resection mortality [odds ratio (OR), 1.0; 95% confidence interval (CI), 0.99-1.00; P=0.438)]. Neural invasion remained an overall independent predictor of mortality following multivariate analysis (OR, 3.94; 95% CI, 1.36-11.40; P=0.011). Patients with higher TVol were more likely to require a vascular resection (P=0.007), had longer surgical times (P<0.001), larger intraoperative blood losses (P=0.007) and a trend toward worse survival (P=0.068). TVol inclusion in a multivariate model resulted in a small improvement in mortality prediction versus TSize (14.9 vs. 14.7%). A higher TVol results in a more complex perioperative course. Although TVol improved the mortality prediction beyond simple TSize alone, this difference was not significant. Studies normalising TVol for body composition are required.

Shear wave elastography for localization of prostate cancer lesions and assessment of elasticity thresholds: implications for targeted biopsies and active surveillance protocols

PURPOSE

Shear wave elastography allows the detection of cancer by using focused ultrasound pulses for locally deforming tissue. The differences in tissue elasticity and stiffness have been used increasingly in breast cancer imaging and help detect potential tumor lesions in the prostate. In this study we localized prostate cancer lesions using shear wave elastography before radical prostatectomy and assessed the examiner independent elasticity threshold for cancer foci detection.

MATERIALS AND METHODS

Shear wave elastography scanning of the whole prostate was performed before radical prostatectomy in 60 consecutive patients with high, intermediate and low risk disease. Localization of suspected lesions and density threshold (kPa) were recorded in up to 12 areas and resulted in 703 different fields. Shear wave elastography findings were correlated with final pathology. Initially 381 areas were used to establish shear wave elastography cutoffs (development cohort 32 patients). Subsequently these cutoffs were validated in 322 areas (validation cohort 28 patients).

RESULTS

Using shear wave elastography significant differences were recorded for the elasticity of benign tissue vs prostate cancer nodules at 42 kPa (range 29 to 71.3) vs 88 kPa (range 54 to 132) (all p <0.001). Median cancer lesion diameter was 26 mm (range 18 to 41). Applying the most informative cutoff of 50 kPa to the validation cohort resulted in 80.9% and 69.1% sensitivity and specificity, respectively, and 74.2% accuracy for detecting cancer nodules based on final pathological finding. The corresponding positive and negative predictive values were 67.1% and 82.2%, respectively.

CONCLUSIONS

Shear wave elastography allows the identification of cancer foci based on shear wave elastography differences. Moreover, reliable cutoffs for this approach can be established, allowing examiner independent localization of prostate cancer foci.

Understanding the relationship between tumor size, gland size, and disease aggressiveness in men with prostate cancer

OBJECTIVE

To determine the relationship between prostate gland and tumor volume in men undergoing radical prostatectomy (RP) for prostate cancer. We hypothesized that larger tumors within smaller prostate glands are associated with more aggressive disease characteristics.

METHODS

Records of patients undergoing RP from 2000-2008 at a single institution were reviewed retrospectively. The dominant nodule was considered to be the largest focus of cancer within the prostate, and the dominant nodule-to-prostate volume ratio (DNVR) was calculated according to the ratio of the dominant nodule volume to the gland weight. Cox regression was performed to assess the relationship between DNVR and both pathologic outcomes (Cancer of the Prostate Risk Assessment post-Surgical score) and biochemical recurrence (BCR).

RESULTS

At a median follow-up of 3.7 years, 174 patients (7.2%) suffered BCR. There was no linear correlation between tumor volume and gland size (R = -0.09). DNVR above the median (≥0.033 cc/gm) was closely associated with high clinicopathologic risk as measured by Cancer of the Prostate Risk Assessment post-Surgical score (hazard ratio, 35.53; 95% confidence interval, 14.42-87.55 for high- vs low-risk groups). In the univariable analysis, both tumor diameter and DNVR were associated with increased risk of BCR. However, in the multivariable model, only tumor diameter remained a significant predictor of BCR (hazard ratio, 2.02; 95% confidence interval, 1.04-3.91).

CONCLUSION

Increased DNVR appears to be a characteristic of aggressive prostate tumors, although it did not predict BCR in the present study. However, these data support the association between tumor diameter and BCR after RP for prostate cancer independent of other key clinicopathologic features.

Combination of clinical characteristics and transrectal ultrasound-guided biopsy to predict lobes without significant cancer: application in patient selection for hemiablative focal therapy

PURPOSE

A major limitation of performing hemiablative focal therapy (FT) for prostate cancer (PCa) is the possibility of accompanying significant cancer in the contralateral side of the prostate that is missed on prostate biopsy. We attempted to verify whether clinical and biopsy-related parameters can be used to predict the absence of significant cancer in the prostate lobe.

METHODS

We assumed that hemiablative FT could be performed in patients with low-risk PCa, with unilateral tumors as assessed by transrectal ultrasound-guided biopsy. We evaluated 214 patients who had undergone radical prostatectomy (RP) and fulfilled the eligibility criteria. Seemingly preserved lobes, defined by the absence of cancer on biopsy, were classified as lobes with no cancer (LNC), lobes with insignificant cancer (LIC), and lobes with significant cancer (LSC) according to RP pathology. Cases with an estimated tumor volume of <0.5 mL, a Gleason score of <7, and organ confinement without Gleason pattern 4 were classified as LIC. Univariate and multivariate logistic regression analyses were performed to identify predictors for LSC. Predictive accuracies of the multivariate models were assessed using receiver operating characteristic curve-derived areas under the curve.

RESULTS

Of 214 evaluated lobes, 45 (21.0%), 62, (29.0%), and 107 (50.0%) were classified as LNC, LIC, and LSC, respectively. Among the clinical and biopsy-related parameters, prostate-specific antigen density and prostate volume were identified as significant predictors for LSC in univariate regression analysis. However, multivariate analysis did not identify an independent predictor. Predictive accuracies of the multivariate models did not exceed 70.4%.

CONCLUSIONS

Conventional parameters have limited value in predicting LSC in patients who are candidates for hemiablative FT.

Maximum tumor diameter and the risk of prostate-specific antigen recurrence after radical prostatectomy

INTRODUCTION/BACKGROUND

The aim of this study was to investigate whether the MTD could identify men at low risk of PSA recurrence after RP who might not benefit from ART despite other adverse features.

PATIENTS AND METHODS

The study cohort consisted of 354 men with T1c to T2 prostate cancer diagnosed between September 2001 and December 2008 who underwent RP without adjuvant therapy. Multivariable Cox regression was used to assess the effect of MTD on the risk of PSA recurrence (> 0.1 ng/mL and verified), adjusting for known predictors.

RESULTS

After a median follow-up of 4.0 years, 34 men (9.6%) experienced PSA failure. In multivariable analysis, increasing MTD was significantly associated with an increased PSA recurrence risk (hazard ratio, 2.74; 95% confidence interval, 1.23-6.10; P = .01) within the interaction model. Estimates of PSA recurrence-free survival stratified around the median MTD value (1.2 cm) were significantly different in men with a pre-RP PSA > 4 ng/mL (P < .001; 5-year estimate: 74.5% vs. 99.0%) but not in men with PSA ≤ 4 ng/mL (P = .59; 5-year estimate: 89.6% vs. 92.6%), consistent with the significant interaction (P = .004) between PSA and MTD. Moreover, in men with a pre-RP PSA > 4 ng/mL these estimates were significantly different if at least 1 adverse feature (pT3, R1, or Gleason score ≥ 8) was present at RP (P = .01; 5-year estimate: 46.6% vs. 100%) versus none (P = .09; 5-year estimate: 93.4% vs. 98.9%).

CONCLUSION

Men with a low MTD (≤ 1.2 cm) appear to be at low risk of PSA recurrence despite adverse features at RP and might not benefit from ART.

Limited ability of existing nomograms to predict outcomes in men undergoing active surveillance for prostate cancer

OBJECTIVE

To assess the ability of current nomograms to predict disease progression at repeat biopsy or at delayed radical prostatectomy (RP) in a prospectively accrued cohort of patients managed by active surveillance (AS).

MATERIALS AND METHODS

A total of 273 patients meeting low-risk criteria who were managed by AS and who underwent multiple biopsies and/or delayed RP were included in the study. The Kattan (base, medium and full), Steyerberg, Nakanishi and Chun nomograms were used to calculate the likelihood of indolent disease ('nomogram probability') as well as to predict 'biopsy progression' by grade or volume, 'surgical progression' by grade or stage, or 'any progression' on repeat biopsy or surgery. We evaluated the associations between each nomogram probability and each progression outcome using logistic regression with (area under the receiver-operating characteristic curve (AUC) values and decision curve analysis.

RESULTS

The nomogram probabilities of indolent disease were lower in patients with biopsy progression (P < 0.01) and any progression on repeat biopsy or surgical pathology (P < 0.05). In regression analyses, nomograms showed a modest ability to predict biopsy progression, adjusted for total number of biopsies (AUC range 0.52-0.67) and any progression (AUC range 0.52-0.70). Decision curve analyses showed that all the nomograms, except for the Kattan base model, have similar value in predicting biopsy progression and any progression. Nomogram probabilities were not associated with surgical progression in a subgroup of 58 men who underwent delayed RP.

CONCLUSIONS

Existing nomograms have only modest accuracy in predicting the outcomes of patients undergoing AS. Improvements to existing nomograms should be made before they are implemented in clinical practice and used to select patients for AS.

Tumor percentage but not number of tumor foci predicts disease-free survival after radical prostatectomy especially in high-risk patients

OBJECTIVE

To evaluate the predictive value of tumor volume (TV), tumor percentage (TP), and number of tumor foci (NF) in patients with prostate cancer. The prognostic relevance of TV, TP, and NF as predictors of biochemical recurrence (BCR) following radical prostatectomy (RPE) is controversial.

PATIENTS AND METHODS

The cohort consisted of 758 referred subjects who underwent RPE between 2000 and 2005 at the University of Muenster. The mean time of follow-up was 62 months. TV, TP, and NF were estimated visually with the assistance of a pathologic mapping grid for embedded whole-mount RPE specimens. In addition, TV and TP were assessed in a categorized fashion by using quartiles as cutoff points. Subgroup analyses for high- and low-risk patients using univariate and multivariate Cox proportional hazard analyses for BCR were performed.

RESULTS

TV, TP, and NF were strongly related to tumor stage, Gleason score, surgical margin status, and preoperative prostate-specific antigen (PSA). In univariate analysis, all pathologic parameters including TV, TP, and NF were predictive for BCR. In multivariate analysis, only TP, tumor stage, and PSA level were independent predictors. In subgroup analysis, TP was an independent predictor for BCR in the high-risk group but not in the low-risk group.

CONCLUSIONS

TP, but not TV or NF, was found to be an independent predictor for BCR in patients after RPE. TP seems to be more relevant in high-risk patients (i.e., any of the following: > pT2, Gleason score > 6, or PSA > 20 ng/ml).

Percentage of high-grade tumour volume does not meaningfully improve prediction of early biochemical recurrence after radical prostatectomy compared with Gleason score

OBJECTIVE

To examine whether percentage of tumour volume (%TV) and percentage of high-grade tumour volume (%HGTV) help to better identify men at higher risk of early biochemical recurrence (BCR) after radical prostatectomy (RP) for non-metastatic high-risk prostate cancer, as early BCR after RP might be associated with higher risk of metastases and cancer-specific mortality.

PATIENTS AND METHODS

We examined the data of 595 men treated with RP for non-metastatic high-risk prostate cancer between 1992 and 2011 at two European tertiary care centres. Kaplan-Meier analyses were used to graphically depict 2-year BCR-free survival. Multivariable Cox regression models addressed early BCR. We tested whether addition of %TV and %HGTV to a multivariable Cox regression model helps to increase a model's predictive accuracy (PA) for prediction of early BCR.

RESULTS

In all, 32 men (10%) with specimen-confined prostate cancer (pT2-pT3a, negative surgical margin, pN0) and 67 men (24%) with non-specimen-confined prostate cancer had early BCR. After stratification according to %HGTV (%HGTV threshold: ≤33.33 vs >33.33%), the 2-year BCR-free survival rates were respectively 93 vs 60% (log-rank P < 0.001). In multivariable Cox regression models %HGTV emerged as an independent predictor of early BCR (P < 0.001), whereas %TV did not (P > 0.05). However, adding %HGTV (regardless of its coding) to other covariates in multivariable Cox regression analysis did not increase the model's PA in a meaningful fashion compared with the use of the detailed Gleason grading system (6 vs 7a vs 7b vs 8 vs 9-10).

CONCLUSIONS

In a large cohort of patients with high-risk prostate cancer, %HGTV and %TV did not improve prediction of early BCR after RP substantially, although %HGTV was an independent predictor of early BCR. Therefore, sophisticated TV/HGTV measurements do not seem to have additional benefit for early BCR prediction relative to the use of Gleason grading. However, these results need to be confirmed in larger, prospective studies.

High percent tumor volume predicts biochemical recurrence after radical prostatectomy in pathological stage T3a prostate cancer with a negative surgical margin

OBJECTIVES

To evaluate the impact of percent tumor volume and surgical margin status on biochemical recurrence in pT3-T4 prostate cancer.

METHODS

A total of 397 patients who had pT3-T4N0 diseases and did not receive neoadjuvant or adjuvant therapy were included for analysis.

RESULTS

In the entire cohort, prostate-specific antigen (per 1 ng/mL increase; hazard ratio 1.019; P = 0.002), pathological stage (T3b-T4 vs T3a; hazard ratio 2.283; P < 0.001), Gleason score (≥8 vs ≤6; hazard ratio 5.290; P = 0.005), surgical margin status (multiple positive vs negative; hazard ratio 1.839; P = 0.003) and lymphovascular invasion (present vs absent; hazard ratio 1.641; P = 0.008) were independent predictors of recurrence. Percent tumor volume was an independent predictor of recurrence in T3a diseases with negative surgical margins. In analysis using receiver operating characteristic curve, a threshold of 12% showed the best balance of sensitivity and specificity, 66% and 67%, respectively. The 5-year recurrence-free survival rates of pT3a diseases with negative surgical margin were 85.2% for percent tumor volume ≤12% and 57.7% for percent tumor volume >12% (P < 0.001). Patients with pT3a with negative surgical margins and percent tumor volume >12% showed comparable 5-year recurrence-free survival rate compared with those with pT3a with positive surgical margin (57.7% vs 57.6%; P = 0.763).

CONCLUSIONS

Despite having less impact on recurrence than other clinicopathological variables in pT3-T4 prostate cancer, percent tumor volume can further improve recurrence risk stratification in pT3a diseases with negative surgical margins.

Tumor volume adds prognostic value in patients with organ-confined prostate cancer

PURPOSE

This study was designed to assess the independent prognostic value of tumor volume (TV) and whether adding TV provides additional prognostic information for predicting biochemical recurrence (BCR) after radical prostatectomy.

METHODS

We reviewed the medical records of 1,129 patients who underwent radical prostatectomy between July 2005 and July 2011. TV was categorized as minimal (≤1.0 ml), moderate (1.1-5.0 ml), or extensive (>5.0 ml). Cox regression analysis was performed to identify independent predictors of BCR. The predictive accuracies of Cox's proportional hazard regression models with and without TV were quantified and compared using time-dependent receiver operating characteristic curve analysis.

RESULTS

Increasing TV was associated with higher prostate specific antigen, pathological Gleason score, and pathologic tumor stage. TV was an independent predictor of BCR in multivariate analysis (p<0.001). When patients were stratified by organ-confined and nonorgan-confined tumor groups, TV remained an independent predictor of BCR in organ-confined tumors (p<0.001). In the nonorgan-confined tumor group, a significant difference was found only between extensive versus minimal TV (p=0.023). The predictive accuracy of the Cox regression model increased significantly by adding TV in organ-confined tumor group (0.748 vs. 0.704, p<0.05) but not in nonorgan-confined group (0.742 vs. 0.734, p>0.05).

CONCLUSIONS

TV was an independent prognostic predictor of BCR in organ-confined prostate cancers and provided additional prognostic information with increased predictive accuracy. In contrast, TV did not increase the predictive accuracy in nonorgan-confined tumor. TV should be considered as a prognosticator in organ-confined tumors.

Active surveillance for low-risk prostate cancer worldwide: the PRIAS study

BACKGROUND

Overdiagnosis and subsequent overtreatment are important side effects of screening for, and early detection of, prostate cancer (PCa). Active surveillance (AS) is of growing interest as an alternative to radical treatment of low-risk PCa.

OBJECTIVE

To update our experience in the largest worldwide prospective AS cohort.

DESIGN, SETTING, AND PARTICIPANTS

Eligible patients had clinical stage T1/T2 PCa, prostate-specific antigen (PSA) ≤ 10 ng/ml, PSA density <0.2 ng/ml per milliliter, one or two positive biopsy cores, and Gleason score ≤ 6. PSA was measured every 3-6 mo, and volume-based repeat biopsies were scheduled after 1, 4, and 7 yr. Reclassification was defined as more than two positive cores or Gleason >6 at repeat biopsy. Recommendation for treatment was triggered in case of PSA doubling time <3 yr or reclassification.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Multivariate regression analysis was used to evaluate predictors for reclassification at repeat biopsy. Active therapy-free survival (ATFS) was assessed with a Kaplan-Meier analysis, and Cox regression was used to evaluate the association of clinical characteristics with active therapy over time.

RESULTS AND LIMITATIONS

In total, 2494 patients were included and followed for a median of 1.6 yr. One or more repeat biopsies were performed in 1480 men, of whom 415 men (28%) showed reclassification. Compliance with the first repeat biopsy was estimated to be 81%. During follow-up, 527 patients (21.1%) underwent active therapy. ATFS at 2 yr was 77.3%. The strongest predictors for reclassification and switching to deferred treatment were the number of positive cores (two cores compared with one core) and PSA density. The disease-specific survival rate was 100%. Follow-up was too short to draw definitive conclusions about the safety of AS.

CONCLUSIONS

Our short-term data support AS as a feasible strategy to reduce overtreatment. Clinical characteristics and PSA kinetics during follow-up can be used for risk stratification. Strict monitoring is even more essential in men with high-risk features to enable timely recognition of potentially aggressive disease and offer curative intervention. Limitations of using surrogate end points and markers in AS should be recognized.

TRIAL REGISTRATION

The current program is registered at the Dutch Trial Register with ID NTR1718 (http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1718).

Trends in prostatic adenocarcinoma tumor volume by visual estimation in prostatectomy specimens

We retrospectively reviewed 1792 consecutive radical prostatectomies (RP) from 2003 to 2006 at a single institution to establish tumor volume reference values, to determine current trends in visually estimated prostate adenocarcinoma tumor volume, and to characterize cases with no residual cancer on RP. Tumor volumes were recorded and subsequently stratified as very low, 0-1%; low, 1.1-10%; intermediate, 10.1-20%; high, 20.1-50%; and very high, >50%, with incidences of 11.7%, 52.1%, 21.5%, 13.2%, and 1.5%, respectively. The incidence of very low volume tumors increased within the time period (p=0.04). Seminal vesicle involvement was detected in 5.0% of cases and lymph node metastasis occurred in 1.4%. Volume categories statistically correlated with seminal vesicle invasion (p=0) and lymph nodes metastases (p=0). Eleven cases of no residual cancer (0.6%) were identified with a non-statically significant increase during the study (p=0.07). The rising incidence of very low volume tumors should be considered by clinicians when discussing treatment options with patients. A discrete tumor volume should be provided for RP specimens as it may be an important prognostic factor.

Advances in imaging and in non-surgical salvage treatments after radiorecurrence in prostate cancer: what does the oncologist, radiotherapist and radiologist need to know?

OBJECTIVES

In this article the state of art the of prostate cancer (Pca) imaging and non-surgical salvage treatments (STs) is surveyed in order to explore the impact of imaging findings on the identification of radiorecurrent Pca after external beam radiotherapy (EBRT).

METHODS

A computerised search was performed to identify all relevant studies in Medline up to 2012. Additional articles were extracted based on recommendations from an expert panel of authors.

RESULTS

Definitive EBRT for Pca is increasingly used as treatment. After radiorecurrent Pca, non-surgical STs are emerging and shifting from investigational status to more established therapeutic options. Therefore, several scientific societies have published guidelines including clinical and imaging recommendations, even if the timing, efficacy and long-term toxicity of these STs have to be established. In some measure, accurately delineating the location and the extent of cancer is critical in selecting target lesions and in identifying patients who are candidates for STs. However, there is increasing awareness that anatomical approaches based on measurements of tumour size have substantial limitations, especially for tumours of unknown activity that persist or recur following irradiation

CONCLUSIONS

To date, the main focus for innovations in imaging is the combination of excellence in anatomical resolution with specific biological correlates that depict metabolic processes and hallmarks at the tumour level. The emergence of new molecular markers could favour the development of methods that directly determine their presence, thereby improving tumour detection.

KEY POINTS

Imaging may influence therapeutic decisions during non-surgical STs. MRI findings correlate with parametric maps derived from multiple functional techniques. Non-surgical salvage treatments allow local tumour control in patients with radiorecurrent PCa.

The prognostic significance of percentage of tumour involvement according to disease risk group in men treated with radical prostatectomy

We investigated the prognostic significance of percentage of tumour involvement (PTI) according to the clinicopathological features of prostate cancer among patients who underwent radical prostatectomy (RP). A retrospective study of 534 patients who underwent RP between September 2003 and March 2008 without any neoadjuvant or adjuvant therapy was performed. The associations of PTI with various clinicopathological features and biochemical recurrence-free survival were examined via uni- and multivariate analyses. The predictive accuracy of the multivariate model was assessed with a receiver operating characteristics-derived area under the curve. PTI was demonstrated to be significantly associated with preoperative prostate-specific antigen (PSA) level (P=0.001), pathological Gleason score (P<0.001), extraprostatic tumour extension (P<0.001), seminal vesicle invasion (P<0.001) and positive surgical margin (P<0.001) in univariate analyses. When patients were stratified into disease risk groups, PTI was an independent predictor of biochemical recurrence-free survival in multivariate analysis only among the low-risk group (P=0.033) but not the intermediate- (P=0.287) or the high-risk groups (P=0.828). The addition of the PTI did not significantly increase the accuracy of the multivariate model devised for the prediction of biochemical recurrence-free survival among both total patients (P=0.459) and the low-risk group (P=0.268), respectively. In conclusion, although PTI appeared to be a more significant prognostic factor among patients with low-risk disease than among those with higher risk diseases, overall, the PTI may not provide additional prognostic information beyond what can already be obtained via established prognostic factors.

Active surveillance for prostate cancer: progress and promise

Widespread prostate-specific antigen (PSA) -based screening and aggressive treatment of prostate cancer have reduced mortality rates substantially, but both remain controversial in large part because of high rates of overdiagnosis and overtreatment of otherwise indolent tumors. Active surveillance--or close monitoring of PSA levels combined with periodic imaging and repeat biopsies--is gaining acceptance as an alternative initial management strategy for men with low-risk prostate cancer. In reported series, rates of progression to active treatment with intermediate-term follow-up have ranged from 14% to 41%, and likelihood of subsequent cure with surgery or radiation does not seem to be compromised by an initial trial of surveillance. Two related challenges to broader acceptance of surveillance are better characterization at time of diagnosis of the risk of progression (including likelihood that given tumor may have been undersampled by diagnostic biopsy) and validation of optimal end points once surveillance begins. Both are subjects of intense ongoing investigation, with emerging biomarkers and novel imaging tests expected to facilitate decision making substantially. Recent reports have suggested active surveillance can be a cost-effective approach and preserve quality of life, but these questions must be assessed more definitively in prospective cohorts. Ultimately, by minimizing the harms of overtreating low-risk prostate cancer, active surveillance may help settle the controversy surrounding prostate cancer screening and management.

Prognostic significance of tumor volume in radical prostatectomy and needle biopsy specimens

PURPOSE

This review addresses the controversies that persist relating to the prognosis and reporting of tumor volume in adenocarcinoma of the prostate.

MATERIALS AND METHODS

A search was performed using the MEDLINE database and referenced lists of relevant studies to obtain articles addressing the quantification of cancer on radical prostatectomy and needle biopsy.

RESULTS

In the 2010 TNM classification system T2 tumor at radical prostatectomy is subdivided into pT2a (unilateral tumor occupying less than ½ a lobe), pT2b (unilateral tumor greater than ½ a lobe) and pT2c (bilateral tumor). This pathological substaging of T2 disease fails on several accounts. In most studies pT2b disease almost does not exist. By the time a tumor is so large that it microscopically occupies more than ½ a lobe, in the majority of cases there is bilateral (pT2c) tumor. An even greater flaw of the substaging system for stage pT2 disease is the lack of prognostic significance. In reporting pathologically organ confined cancer, it should be merely noted as pT2 without further subclassification. The data are conflicting as to the independent prognostic significance of objective measurements of tumor volume in radical prostatectomy specimens. The most likely explanation for the discordant results lies in the strong correlation of tumor volume with other prognostic markers such as extraprostatic extension and positive margins. In studies where it is statistically significant on multivariate analysis, it is unlikely that knowing tumor volume improves prediction of prognosis beyond routinely reported parameters to the degree that it would be clinically useful for an individual patient. An alternative is to record tumor volume as minimal, moderate or extensive, which gives some indication to the urologist as to the extent of disease. Not only does providing an objective measurement not add useful prognostic information beyond what is otherwise routinely reported by the pathologist, but many objective measurements done in routine practice will likely not be an accurate indicator of the true tumor volume. There is also a lack of consensus regarding the best method of measuring tumor length when there are multiple foci in a single core separated by benign intervening prostatic stroma. Some pathologists, this author included, consider discontinuous foci of cancer as if it was 1 uninterrupted focus, the rationale being that these discontinuous foci are undoubtedly the same cancer going in and out of the plane of section. Measuring the cancer from where it starts to where it ends on the core gives the minimal length of cancer in the prostate. Others measure each focus individually, and the sum of these measurements is considered the cancer length on the core. Quantifying cancer with an ocular micrometer to record the total length or percent length of cancer is time-consuming, and the data are conflicting whether this is superior to other, simpler methods and whether any potential differences in predictive accuracy would translate into changes in clinical management. It is recommended that at a minimum the number of positive cores be recorded, unless fragmented involved cores preclude evaluation, along with at least 1 other more detailed measurement such as the percent of core involvement or length of cancer.

CONCLUSIONS

Consensus has been reached on some of the issues relating to quantifying tumor volume in prostate cancer, such as the lack of utility of substaging pT2 disease. Other questions such as whether to include or subtract intervening benign prostate tissue on prostate needle cores will require additional studies. Finally, matters such as the need to quantify cancer at radical prostatectomy or which method of quantifying cancer on needle biopsy is superior will likely remain contentious due to the close interrelationship and redundancy of prognostic variables.

Prostate volume has prognostic value only in pathologic T2 radical prostatectomy specimens

The objective of this study was to evaluate the prognostic roles of the prostate volume, tumor volume, and tumor percentage as a function of the pathologic T stage in radical prostatectomy specimens. This study included 259 patients who underwent radical prostatectomy between 2005 and 2010. The mean follow-up period was 41.2 months. In all of the specimens, prostate volume (P = 0.021), the Gleason score (P = 0.035), and seminal vesicle invasion (P = 0.012) were independent predictors of biochemical recurrence (BCR). In the T2 group, multivariate analysis showed that the BCR was significantly associated with prostate specific antigen (PSA) (P = 0.028), a lower prostate volume (P = 0.004), and the Gleason score (P = 0.040). The Kaplan-Meier survival curve showed that a smaller prostate volume was significantly associated with a greater risk of BCR (< 30 vs ≥ 30 mL; P = 0.010). In the T3 group, patients with seminal vesicle invasion had a significantly shorter mean BCR-free survival (P = 0.030). In this study, tumor volume and tumor percentage did not predict BCR. Notably, a lower prostate volume is an independent predictor for BCR only in the organ-confined radical prostatectomy specimens. But, prostate volume could not predict BCR in most locally advanced tumors.

Tumor volume as a predictor of adverse pathologic features and biochemical recurrence (BCR) in radical prostatectomy specimens: a tale of two methods

PURPOSE

The prognostic value of tumor volume in predicting biochemical recurrence after prostatectomy has been debated. Our aim in this study was to (a) evaluate tumor volume as an independent predictor of adverse pathologic outcomes and BCR and (b) determine the effect of two different methods of tumor volume estimation.

METHODS

We reviewed the charts of 3,087 patients who underwent radical prostatectomy at Vanderbilt University Medical Center between 2000 and 2008; of which 1,747 patients had data sufficient for analysis. Prostate specimens were processed as whole mount between 2000 and 2003 and then via systematic sampling from 2003 to 2008, with tumor volume measured by planimetry in the whole-mount group and tumor volume estimated by percent tumor involvement in the systematic sampling group.

RESULTS

Tumor volume estimates were higher with SS than with WM. There were significant associations between larger tumor volume and adverse pathological outcomes, regardless of pathologic method (all with P<0.001). Controlling for other pathologic parameters, tumor volume was an independent predictor of PGS, EPE, and SM in logistic regression models (P<0.001 for TV in all models). Tumor volume was demonstrated to be an independent predictor of BCR in the WM group (1.06, 95% CI 1.01-1.11, P=0.013), though tumor volume was not a significant predictor of BCR in the SS group.

CONCLUSIONS

Though the prognostic value of tumor volume is debated, our data demonstrate that tumor volume, when calculated via planimetry on whole-mount pathologic sectioning, is a significant predictor of biochemical recurrence after prostatectomy.

A critical analysis of the tumor volume threshold for clinically insignificant prostate cancer using a data set of a randomized screening trial

PURPOSE

The identification of clinically insignificant prostate cancer could help avoid overtreatment. Current criteria for insignificant prostate cancer use a tumor volume threshold of less than 0.5 ml for the index tumor. In this study we reassess this tumor volume threshold for clinically insignificant prostate cancer using an independent data set.

MATERIALS AND METHODS

The rate of insignificant prostate cancer was calculated by modeling lifetime risk estimates of prostate cancer diagnosis in screened and nonscreened participants in a randomized prostate cancer screening trial. Using lifetime risk estimates 50.8% of screen detected prostate cancer was calculated to be clinically insignificant and the 49.2% largest tumor volume of 325 prostatectomy specimens was used to determine the threshold tumor volume for insignificant prostate cancer. Because stage and grade represent the strongest determinants of cancer aggressiveness, we also calculated the tumor volume threshold for insignificant cancer after the selection of patients with organ confined prostate cancer without Gleason pattern 4/5. The analyses were performed for total tumor volume and for index tumor volume.

RESULTS

The minimum threshold tumor volume of the index tumor and total tumor was 0.55 and 0.70 ml, respectively. After accounting for tumor stage and grade we obtained a threshold volume for the index tumor and total tumor of 1.3 and 2.5 ml, respectively.

CONCLUSIONS

We confirmed the original value of the index tumor volume threshold of 0.5 ml for insignificant prostate cancer, and we demonstrated that clinically insignificant prostate cancer may include index Gleason score 6, pT2 tumors with volumes up to at least 1.3 ml. These results suggest a reconsideration of current methods and nomograms used for pretreatment risk assessment.