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

Tumor Location and a Tumor Volume over 2.8 cc Predict the Prognosis for Japanese Localized Prostate Cancer

(1) Objective: Our study investigated the prognostic value of tumor volume and location in prostate cancer patients who received radical prostatectomy (RP). (2) Methods: The prognostic significance of tumor volume and location, together with other clinical factors, was studied using 557 patients who received RP. (3) Results: The receiver operating characteristic (ROC) curve identified the optimal cutoff value of tumor volume as 2.8 cc for predicting biochemical recurrence (BCR). Cox regression analysis revealed that a tumor in the posterior area (p = 0.031), peripheral zone (p = 0.0472), and tumor volume ≥ 2.8 cc (p < 0.0001) were predictive factors in univariate analysis. After multivariate analysis, tumor volume ≥ 2.8 cc (p = 0.0225) was an independent predictive factor for BCR. Among them, a novel risk model was established using tumor volume and location in the posterior area and peripheral zone. The progression-free survival (PFS) of patients who met the three criteria (unfavorable group) was significantly worse than other groups (p ≤ 0.001). Furthermore, multivariate analysis showed that the unfavorable risk was an independent prognostic factor for BCR. The prognostic significance of our risk model was observed in low- to intermediate-risk patients, although it was not observed in high-risk patients. (4) Conclusion: Tumor volume (≥2.8 cc) and localization (posterior/peripheral zone) may be a novel prognostic factor in patients undergoing RP.

Predicting Biochemical Failure in Irradiated Patients With Prostate Cancer by Tumour Volume Measured by Multiparametric MRI

BACKGROUND/AIM

We examined the prognostic value of intraprostatic gross tumour volume (GTV) as measured by multiparametric MRI (mpMRI) in patients with prostate cancer following (primary) external beam radiation therapy (EBRT).

PATIENTS AND METHODS

In a retrospective monocentric study, we analysed patients with prostate cancer (PCa) after EBRT. GTV was delineated in pre-treatment mpMRI (GTV-MRI) using T2-weighted images. Cox-regression analyses were performed considering biochemical failure recurrence-free survival (BRFS) as outcome variable.

RESULTS

Among 131 patients, after a median follow-up of 57 months, biochemical failure occurred in 27 (21%). GTV-MRI was not correlated with % of positive biopsy cores, Gleason score and initial PSA (all r<0.2) and only moderately correlated with cT stage (r=0.32). In univariate analysis, cT stage, Gleason score and GTV-MRI were higher in subjects with shorter BRFS (p<0.05). GTV-MRI remained a significant predictor for BRFS in multivariate analyses, independent of Gleason score and cT stage.

CONCLUSION

GTV, defined using mpMRI, provides incremental prognostic value for BRFS, independent of established risk factors. This supports the implementation of imaging-based GTV for risk-stratification, although further validation is needed.

Specific spatial distribution patterns of tumor foci are associated with a low risk of biochemical recurrence in pT2pN0R0 prostate cancer

BACKGROUND

The previous attempts for pT2 substaging of prostate cancer (PCa) were insufficient in providing prognostic subgroups and the search for new prognostic parameters to subcategorize pT2 PCa is, therefore, needed. Therefore, the current study investigated the association between tumor distribution patterns and the biochemical recurrence (BCR)-free survival rate in pT2pN0R0 PCa.

METHODS

Following radical prostatectomy, the anatomical distribution of PCa in 743 men with pT1-pT3pN0 disease was analyzed to determine 20 types of PCa distribution patterns. Then, 245 men with pT2pN0R0 PCa was considered for prognostic evaluation with a mean follow-up period of 60 months. The spatial distribution patterns of PCa were evaluated using a cMDX^©-based map model of the prostate. An analysis including 552,049 comparison operations was performed to assist in the evaluation of the similarity levels of the distribution patterns. A k-mean cluster analysis was applied to determine groups with similar distribution patterns. A decision-tree analysis was performed to divide these groups according to frequency of BCR. The BCR-free survival rate was analyzed using Kaplan-Meier curves. Predictors of progression were investigated using a Cox proportional hazards model.

RESULTS

BCR occurred in 8.2% of the 245 men with pT2pN0R0 PCa. The median time of recurrence was 60 months (interquartile range [IQR]: 42-77). In univariate and multivariate analyses, the prostate volume and the distribution patterns were independent predictors for BCR, whereas the sub-staging of pT2 tumors, Gleason grading, prostate-specific antigen (PSA) level, and relative tumor volume were not. In the patients with pT2pN0R0 disease, PCa distribution patterns with the apical involvement were significantly associated with the risk of BCR (P = 0.001).

CONCLUSION

The spread tumor patterns with the apical involvement are associated with a high-risk of BCR in the pT2 tumor stage. The vertical tumor spread could be considered in developing improved prognostic pT2 sub-categories.

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.

Effect of observation size and apparent diffusion coefficient (ADC) value in PI-RADS v2.1 assessment category 4 and 5 observations compared to adverse pathological outcomes

OBJECTIVE

To compare observation size and apparent diffusion coefficient (ADC) values in Prostate Imaging Reporting and Data System (PI-RADS) v2.1 category 4 and 5 observations to adverse pathological features.

MATERIALS AND METHODS

With institutional review board approval, 267 consecutive men with 3-T MRI before radical prostatectomy (RP) between 2012 and 2018 were evaluated by two blinded radiologists who assigned PI-RADS v2.1 scores. Discrepancies were resolved by consensus. A third blinded radiologist measured observation size and ADC (ADC.mean, ADC.min [lowest ADC within an observation], ADC.ratio [ADC.mean/ADC.peripheral zone {PZ}]). Size and ADC were compared to pathological stage and Gleason score (GS) using t tests, ANOVA, Pearson correlation, and receiver operating characteristic (ROC) analysis.

RESULTS

Consensus review identified 267 true positive category 4 and 5 observations representing 83.1% (222/267) PZ and 16.9% (45/267) transition zone (TZ) tumors. Inter-observer agreement for PI-RADS v2.1 scoring was moderate (K = 0.45). Size was associated with extra-prostatic extension (EPE) (19 ± 8 versus 14 ± 6 mm, p < 0.001) and seminal vesicle invasion (SVI) (24 ± 9 versus 16 ± 7 mm, p < 0.001). Size ≥ 15 mm optimized the accuracy for EPE with area under the ROC curve (AUC) and sensitivity/specificity of 0.68 (CI 0.62-0.75) and 63.2%/65.6%. Size ≥ 19 mm optimized the accuracy for SVI with AUC/sensitivity/specificity of 0.75 (CI 0.66-0.83)/69.4%/70.6%. ADC metrics were not associated with pathological stage. Larger observation size (p = 0.032), lower ADC.min (p = 0.010), and lower ADC.ratio (p = 0.010) were associated with higher GS. Size correlated better to higher Gleason scores (p = 0.002) compared to ADC metrics (p = 0.09-0.11).

CONCLUSION

Among PI-RADS v2.1 category 4 and 5 observations, size was associated with higher pathological stage whereas ADC metrics were not. Size, ADC.minimum, and ADC.ratio differed in tumors stratified by Gleason score.

KEY POINTS

• Among PI-RADS category 4 and 5 observations, size but not ADC can differentiate between tumors by pathological stage. • An observation size threshold of 15 mm and 19 mm optimized the accuracy for diagnosis of extra-prostatic extension and seminal vesicle invasion. • Among PI-RADS category 4 and 5 observations, size, ADC.minimum, and ADC.ratio differed comparing tumors by Gleason score.

The prognostic impact of downgrading and upgrading from biopsy to radical prostatectomy among men with Gleason score 7 prostate cancer

BACKGROUND

Recently, a new prostate cancer (PC) grading system was introduced, where Gleason score (GS) 7 was divided into 3 + 4 = 7 and 4 + 3 = 7 due to the different prognoses associated with each tumor type. However, whether downgrading or upgrading from needle biopsy (NB) to radical prostatectomy (RP) affects oncologic outcomes is currently unknown. Herein, we investigated the prognostic impact of downgrading and upgrading from NB to RP among men with GS 7 PC.

METHODS

We retrospectively reviewed the medical records of 3003 patients with localized PC who underwent RP between 2005 and 2014. We included 692 patients with GS 7 PC on both NB and RP specimens. We analyzed the data using Kaplan-Meier methods and Cox proportional hazard models.

RESULTS

Of the 692 patients enrolled in this study, 389 (56.2%) and 303 (43.8%) patients had RP GS 3 + 4 = 7 and RP GS 4 + 3 = 7 PC, respectively. On the basis of NB and RP GS, 264 (38.1%), 125 (18.1%), 142 (20.5%), and 161 (23.3%) patients were classified as 3 + 4/3 + 4, 4 + 3/3 + 4, 3 + 4/4 + 3, and 4 + 3/4 + 3, respectively. Kaplan-Meier curves showed significant differences in biochemical recurrence (BCR)-free survival across the groups (P < .001). In the multivariate analyses, these groups were significantly associated with BCR (4 + 3/3 + 4: hazard ratio [HR], 1.675; 3 + 4/4 + 3: HR, 1.908; and 4 + 3/4 + 3: HR, 2.699).

CONCLUSIONS

Downgrading and upgrading from NB to RP was an independent predictor of BCR in men with GS 7 PC, which could be due to the amount of Gleason pattern 4.

Tumor Volume Index as a Prognostic Factor in Patients after Curative Esophageal Cancer Resection

BACKGROUND

The tumor, node, metastasis classification system for staging esophageal cancer does not include tumor volume although it may be an important prognostic factor. We evaluated the prognostic value of tumor volume in esophageal cancer.

METHODS

We performed a retrospective study in patients with histologically confirmed primary esophageal cancer who underwent curative esophagectomy at our facility between April 1992 and December 2013. The Tumor Depth Parameter (TDP) was defined as mucosa = 1, submucosa = 2, muscularis propria = 3, adventitia = 4, and invasion into adjacent organs = 5. The pathological Tumor Volume Index (TVI) was defined as the major axis × the minor axis × TDP. The appropriate tumor diameter and TVI cutoff values were determined by the Youden index obtained from the receiver operating characteristic curve. Prognostic factors for overall survival were evaluated by univariate analysis and Cox proportional hazards regression models.

RESULTS

We enrolled 302 patients. In the univariate analysis, patient age and sex, thoracoscopic surgery, tumor depth of invasion and diameter, lymph node metastasis, and the TVI were significantly associated with overall survival. In our multivariate analysis, patient age and sex, thoracoscopic surgery, lymph node metastasis, and the TVI were independently associated with overall survival.

CONCLUSIONS

The pathological TVI was an independent prognostic factor in patients with esophageal carcinoma and could be included in the staging system of esophageal cancer.

Prospective comparison of PI-RADS version 2 and qualitative in-house categorization system in detection of prostate cancer

BACKGROUND

Prostate Imaging-Reporting and Data System v. 2 (PI-RADSv2) provides standardized nomenclature for interpretation of prostate multiparametric MRI (mpMRI). Inclusion of additional features for categorization may provide benefit to stratification of disease.

PURPOSE

To prospectively compare PI-RADSv2 to a qualitative in-house system for detecting prostate cancer on mpMRI.

STUDY TYPE

Prospective.

POPULATION

In all, 338 patients who underwent mpMRI May 2015-May 2016, with subsequent MRI/transrectal ultrasound fusion-guided biopsy.

FIELD STRENGTH

3T mpMRI (T2 W, diffusion-weighted [DW], apparent diffusion coefficient [ADC] map, b-2000 DWI acquisition, and dynamic contrast-enhanced [DCE] MRI).

ASSESSMENT

One genitourinary radiologist prospectively read mpMRIs using both in-house and PI-RADSv2 5-category systems.

STATISTICAL TEST

In lesion-based analysis, overall and clinically significant (CS) tumor detection rates (TDR) were calculated for all PI-RADSv2 and in-house categories. The ability of each scoring system to detect cancer was assessed by area under receiver operator characteristic curve (AUC). Within each PI-RADSv2 category, lesions were further stratified by their in-house categories to determine if TDRs can be increased by combining features of both systems.

RESULTS

In 338 patients (median prostate-specific antigen [PSA] 6.5 [0.6-113.6] ng/mL; age 64 [44-84] years), 733 lesions were identified (47% tumor-positive). Predictive abilities of both systems were comparable for all (AUC 76-78%) and CS cancers (AUCs 79%). The in-house system had higher overall and CS TDRs than PI-RADSv2 for categories 3 and 4 (P < 0.01 for both), with the greatest difference between the scoring systems seen in lesions scored category 4 (CS TDRs: in-house 65%, PI-RADSv2 22.1%). For lesions categorized as PI-RADSv2 = 4, characterization of suspicious/indeterminate extraprostatic extension (EPE) and equivocal findings across all mpMRI sequences contributed to significantly different TDRs for both systems (TDR range 19-75%, P < 0.05).

DATA CONCLUSION

PI-RADSv2 behaves similarly to an existing validated system that relies on the number of sequences on which a lesion is seen. This prospective evaluation suggests that sequence positivity and suspicion of EPE can enhance PI-RADSv2 category 4 cancer detection.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:1326-1335.

A prospective study evaluating indirect MRI-signs for the prediction of extraprostatic disease in patients with prostate cancer: tumor volume, tumor contact length and tumor apparent diffusion coefficient

OBJECTIVE

The aim of this study was to evaluate three indirect MRI signs for predicting extraprostatic disease in patients referred to radical prostatectomy: index tumor volume (MTV), apparent diffusion coefficient (ADC) and tumor contact length (TCL).

MATERIALS AND METHODS

This prospective study included 183 patients with biopsy proven prostate cancer. In all patients the MTV (ml), ADC (× 10^-5 mm²/s) and TCL (mm) of the index tumor were registered at the preoperative MRI. Whole-mounted microscopical examination classified each patient as having either localized- or extraprostatic disease. The Youden index was used to identify the optimal cut-off values for predicting extraprostatic disease. Univariate regression analyses were conducted to estimate the odds ratio (OR) with 95% confidence intervals (CI). Results were stratified upon zonal location of the index tumor.

RESULTS

Extraprostatic disease was identified in 103 (56%) patients. The risk of extraprostatic disease was nine times higher in peripheral zone tumors with ADC ≤ 89 (OR 9.1, 95% CI 4.2-19.6), five times higher in MTV ≥ 0.9 ml (OR 5.5, 95% CI 2.6-11.4) and five times higher in case of TCL ≥ 14 mm (OR 4.9, 95% CI 2.3-10.2). None of the indirect MRI signs could predict extraprostatic disease for transition zone tumors.

CONCLUSION

The MTV, ADC and TCL are all significant predictors of extraprostatic disease for peripheral zone tumors, while none of the indirect signs were useful for transition zone tumors.

Association between very small tumour size and increased cancer-specific mortality after radical prostatectomy in lymph node-positive prostate cancer

OBJECTIVE

To determine whether very small prostate cancers present in patients who also have lymph node (LN) metastases represent a particularly aggressive disease variant compared with larger LN-positive tumours.

PATIENTS AND METHODS

We identified 37 501 patients diagnosed with prostate cancer between 1988 and 2001 treated with radical prostatectomy within the Surveillance, Epidemiology, and End Results database. The primary study variables were tumour size by largest dimension (stratified into: (i) microscopic focus only or 1 mm; (ii) 2-15 mm; (iii) 16-30 mm; (iv) >30 mm), regional LN involvement, and the corresponding interaction term. We evaluated the risk of 10-year prostate cancer-specific mortality (PCSM) using the Fine and Gray model for competing risks after controlling for race, tumour grade, T stage, receipt of radiation, number of dissected LNs, number of positive LNs, year of diagnosis, and age at diagnosis.

RESULTS

The median follow-up was 11.8 years. There was a significant interaction between tumour size and LN involvement (P-interaction <0.001). In the absence of LN involvement (36 561 patients), the risk of 10-year PCSM increased monotonically with increasing tumour size. Among patients with LN involvement (940), those with the smallest tumours had increased 10-year PCSM compared with patients with tumours sized 2-15 mm (24.7% vs 11.8%; adjusted hazard ratio [AHR] 2.84, 95% confidence interval [CI] 1.21-6.71; P = 0.017) or 16-30 mm (24.7% vs 15.5%; AHR 3.12, 95% CI 1.51-6.49; P = 0.002), and similar 10-year PCSM as those with tumours >30 mm (24.7% vs 24.9%; P = 0.156).

CONCLUSION

In patients with prostate cancer with LN involvement, very small tumour size may predict for higher PCSM compared with some larger tumours, even after controlling for other prognostic variables. These tumours might be particularly aggressive, beyond what is captured by pathological assessment of tumour grade and stage.

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.

Prostate cancer risk alleles are associated with prostate cancer volume and prostate size

PURPOSE

Genome-wide association studies have identified an increasing number of single nucleotide polymorphisms associated with prostate cancer risk. Some of these genetic variants are also associated with serum prostate specific antigen levels and lower urinary tract symptoms, raising the question of whether they are truly prostate cancer biomarkers or simply lead to detection bias. Therefore, we determined whether single nucleotide polymorphisms associated with prostate cancer risk are more strongly associated with tumor or prostate volume.

MATERIALS AND METHODS

The genotypes of 38 validated prostate cancer risk single nucleotide polymorphisms were determined in 1,321 white men who underwent radical prostatectomy. Univariate and multivariate analyses were performed to compare the relationship of single nucleotide polymorphism frequency with total prostate and tumor volumes.

RESULTS

On multivariate analysis 2 single nucleotide polymorphisms on chromosome 8q24, rs16901979 (A) and rs6983267 (G), were significantly associated with increased tumor volume (p=0.01 and 0.02, respectively). In contrast, rs17632542 (T) near the PSA gene on 19q13 was associated with significantly lower tumor volume and rs10788160 (A) on 10q26 was associated with significantly larger prostate volume (p=0.02 and 0.01, respectively).

CONCLUSIONS

Analysis of 38 single nucleotide polymorphisms associated with prostate cancer risk revealed a significant association between several on chromosome 8q24 and increased tumor volume but not prostate volume. This suggests that they are bona fide markers of prostate cancer susceptibility and possibly more aggressive disease. Other prostate cancer risk alleles are associated with prostate specific antigen and increased prostate or decreased tumor volume, suggesting detection bias due to their phenotypic influence.