Clinical significance of unfavorable findings in intermediate-risk prostate cancer patients for predicting treatment outcomes after contemporary, dose-escalated multimodal radiotherapy.

PURPOSE: Few studies have documented the long-term oncological outcomes of favorable and unfavorable intermediate-risk (IR) prostate cancer patients treated via contemporary high-dose irradiation. We analyzed the ultimate clinical outcomes of such patients using the current risk sub-stratification schema. PATIENTS AND METHODS: We included 693 patients with localized IR prostate cancer treated via low-dose-rate brachytherapy (LDR-BT) with or without external beam radiation (EBRT) and with or without androgen-deprivation therapy (ADT) in a single institution. Treatment outcomes (biochemical recurrence-free survival [BCRFS] and clinical progression-free survival [CPFS]) were compared according to the numbers of unfavorable findings. RESULTS: Out of the 693 IR patients, 292 (42.1%) exhibited favorable disease; the remaining 401 (57.9%) exhibited unfavorable disease. Compared with favorable IR status, unfavorable IR status was associated with shorter BCRFS and CPFS (p < 0.001 and p < 0.001, respectively). Patients with two to three unfavorable factors experienced the worst oncological outcomes (p < 0.001 and p < 0.001). Although patients with one or no unfavorable factors responded similarly to LDR-BT monotherapy, this treatment modality was insufficient for preventing biochemical and clinical progression in patients with multiple unfavorable findings. CONCLUSION: Long-term treatment outcomes indicate that patients with IR disease scheduled for LDR-BT should undergo multimodal irradiation if they exhibit two or more unfavorable factors at diagnosis.

Detectable end of radiation prostate specific antigen assists in identifying men with unfavorable intermediate-risk prostate cancer at high risk of distant recurrence and cancer-specific mortality.

BACKGROUND: Undetectable End of Radiation PSA (EOR-PSA) has been shown to predict improved survival in prostate cancer (PCa). While validating the unfavorable intermediate-risk (UIR) and favorable intermediate-risk (FIR) stratifications among Johns Hopkins PCa patients treated with radiotherapy, we examined whether EOR-PSA could further risk stratify UIR men for survival. METHODS: A total of 302 IR patients were identified in the Johns Hopkins PCa database (178 UIR, 124 FIR). Kaplan-Meier curves and multivariable analysis was performed via Cox regression for biochemical recurrence free survival (bRFS), distant metastasis free survival (DMFS), and overall survival (OS), while a competing risks model was used for PCa specific survival (PCSS). Among the 235 patients with known EOR-PSA values, we then stratified by EOR-PSA and performed the aforementioned analysis. RESULTS: The median follow-up time was 11.5 years (138 months). UIR was predictive of worse DMFS and PCSS (P = 0.008 and P = 0.023) on multivariable analysis (MVA). Increased radiation dose was significant for improved DMFS (P = 0.016) on MVA. EOR-PSA was excluded from the models because it did not trend towards significance as a continuous or binary variable due to interaction with UIR, and we were unable to converge a multivariable model with a variable to control for this interaction. However, when stratifying by detectable versus undetectable EOR-PSA, UIR had worse DMFS and PCSS among detectable EOR-PSA patients, but not undetectable patients. UIR was significant on MVA among detectable EOR-PSA patients for DMFS (P = 0.021) and PCSS (P = 0.033), while RT dose also predicted PCSS (P = 0.013). CONCLUSIONS: EOR-PSA can assist in predicting DMFS and PCSS among UIR patients, suggesting a clinically meaningful time point for considering intensification of treatment in clinical trials of intermediate-risk men.

Number of Unfavorable Intermediate-Risk Factors Predicts Pathologic Upstaging and Prostate Cancer-Specific Mortality Following Radical Prostatectomy: Results From the SEARCH Database.

BACKGROUND: To validate and further improve the stratification of intermediate risk prostate cancer into favorable and unfavorable subgroups for patients undergoing radical prostatectomy. MATERIALS AND METHODS: The SEARCH database was queried for IR patients undergoing radical prostatectomy without adjuvant radiotherapy. UIR disease was defined any patient with at least one unfavorable risk factor (URF), including primary Gleason pattern 4, 50% of more biopsy cores containing cancer, or multiple National Comprehensive Cancer Network IR factors. RESULTS: One thousand five hundred eighty-six patients with IR prostate cancer comprised the study cohort. Median follow-up was 62 months. Patients classified as UIR were significantly more likely to have pathologic high-risk features, such as Gleason score 8 - 10, pT3-4 disease, or lymph node metastases, than FIR patients (P < 0.001). Furthermore, UIR patients had significantly higher rates of PSA-relapse (PSA, hazard ratio [HR] = 1.89, P < 0.001) and distant metastasis (DM, HR = 2.92, P = 0.001), but no difference in prostate cancer-specific mortality (PCSM) or all-cause mortality in multivariable analysis. On secondary analysis, patients with ≥2 URF had significantly worse PSA-RFS, DM, and PCSM than those with 0 or 1 URF. Moreover, 40% of patients with ≥2 URF had high-risk pathologic features. CONCLUSIONS: Patients with UIR prostate cancer are at increased risk of PSA relapse, DM, and pathologic upstaging following prostatectomy. However, increased risk of PCSM was only detected in those with ≥2 URF. This suggests that further refinement of the UIR subgroup may improve risk stratification. Prostate Prostate 77:154-163, 2017. © 2016 Wiley Periodicals, Inc.

Modified risk stratification grouping using standard clinical and biopsy information for patients undergoing radical prostatectomy: Results from SEARCH.

INTRODUCTION: Prostate cancer is a heterogeneous disease, and risk stratification systems have been proposed to guide treatment decisions. However, significant heterogeneity remains for those with unfavorable-risk disease. METHODS: This study included 3335 patients undergoing radical prostatectomy without adjuvant radiotherapy in the SEARCH database. High-risk patients were dichotomized into standard and very high-risk (VHR) groups based on primary Gleason pattern, percentage of positive biopsy cores (PPBC), number of NCCN high-risk factors, and stage T3b-T4 disease. Similarly, intermediate-risk prostate cancer was separated into favorable and unfavorable groups based on primary Gleason pattern, PPBC, and number of NCCN intermediate-risk factors. RESULTS: Median follow-up was 78 months. Patients with VHR prostate cancer had significantly worse PSA relapse-free survival (PSA-RFS, P < 0.001), distant metastasis (DM, P = 0.004), and prostate cancer-specific mortality (PCSM, P = 0.015) in comparison to standard high-risk (SHR) patients in multivariable analyses. By contrast, there was no significant difference in PSA-RFS, DM, or PCSM between SHR and unfavorable intermediate-risk (UIR) patients. Therefore, we propose a novel risk stratification system: Group 1 (low-risk), Group 2 (favorable intermediate-risk), Group 3 (UIR and SHR), and Group 4 (VHR). The c-index of this new grouping was 0.683 for PSA-RFS and 0.800 for metastases, compared to NCCN-risk groups which yield 0.666 for PSA-RFS and 0.764 for metastases. CONCLUSIONS: Patients classified as VHR have markedly increased rates of PSA relapse, DM, and PCSM in comparison to SHR patients, whereas UIR and SHR patients have similar prognosis. Novel therapeutic strategies are needed for patients with VHR, likely involving multimodality therapy.

Androgen deprivation therapy and the risk of death from prostate cancer among men with favorable or unfavorable intermediate-risk disease.

BACKGROUND: Radiotherapy (RT), short-course androgen deprivation therapy (ADT), and brachytherapy in various combinations are treatment options for patients with intermediate-risk prostate cancer (PC), but the question of which combination if any is necessary to minimize PC-specific mortality (PCSM) risk in patients with favorable or unfavorable intermediate-risk PC is unknown. The authors assessed PCSM risk after commonly used treatments. METHODS: The cohort consisted of 2510 men with favorable (1902 men; 75.78%) or unfavorable (608 men; 24.22%) intermediate-risk PC who were treated from 1997 to 2013. Treatment included brachytherapy with or without neoadjuvant ADT among men with favorable disease and brachytherapy with neoadjuvant RT or ADT among men with unfavorable disease. Fine and Gray's competing-risks regression model was used to assess whether ADT among men with favorable disease or RT or ADT among men with unfavorable disease decreased PCSM risk after adjusting for treatment propensity score, year of brachytherapy, and PC prognostic factors. RESULTS: After a median follow-up of 7.78 years, 366 deaths (14.58%) were observed, 29 of which (7.92%) were from PC. There was a significant reduction in PCSM risk in men with unfavorable disease who were treated with ADT versus RT (adjusted hazard ratio, 0.34; 95% confidence interval, 0.13-0.91 [P = .03]), but no significant difference in PCSM risk in men with favorable disease who received ADT and brachytherapy versus brachytherapy (adjusted hazard ratio, 0.67; 95% confidence interval, 0.18-2.57 [P =.56]). CONCLUSIONS: Neoadjuvant ADT does not appear to reduce PCSM risk in men undergoing brachytherapy for favorable intermediate-risk PC and should not be considered a standard; however, it appears superior to neoadjuvant RT in men with unfavorable intermediate-risk PC undergoing brachytherapy, making neoadjuvant ADT and brachytherapy a preferred option in these men.

LDR-Brachytherapy monotherapy appears unsuited for NCCN unfavorable intermediate-risk prostate cancer patients.

BACKGROUND: To validate the subdivision of intermediate-risk (IR) prostate cancer (PCa) into favorable intermediate-risk (FIR) and unfavorable intermediate-risk (UIR) PCa in a historical patient cohort and to compare 2 different radiotherapy regimens. METHODS: Patients with intermediate-risk (IR) PCa, treated either by 125J-LDR-brachytherapy monotherapy (BT) or by combined-modality radiation therapy (CRT), were retrospectively subclassified into FIR and UIR and reanalyzed with regard to biochemical recurrence-free survival (BRFS), metastasis-free survival (MFS), and prostate cancer-specific survival (CSS). Kaplan-Meier product-limit method and log-rank tests were applied to estimate survival probabilities and compare survival, respectively. Uni- and multivariable analyses were performed using Cox proportional hazard regression. RESULTS: Of 490 IR patients, 252 had received BT (86.5% FIR, 13.5% UIR), and 238 had received CRT (30% FIR, 70% UIR). Retrospective analysis revealed that BRFS at 10 years was 81% for BT, and 94% for CRT in FIR patients. For UIR patients, BRFS at 10 years was 37% for BT, and 89% for CRT. MFS at 10 years for FIR patients was 87% for BT, and 94% for CRT. For UIR patients MFS at 10 years was 78% for BT, and 95% for CRT. In multivariable analysis treatment (BT vs. CRT) was the single associated factor for biochemical recurrence, and for metastases in the UIR group (BFRS, P < 0.001, HR 16.07 (CI 4.23-61.10); MFS, P = 0.011, HR 8.43 (CI 1.62-43.9). CONCLUSIONS: Subclassification of IR prostate cancer into FIR and UIR subcategories appears mandatory. For FIR patients, outcomes after BT monotherapy were acceptable. However, clinical failure after 125J-LDR-BT in UIR patients was notably increased, suggesting that BT monotherapy was less successful in this risk group. In contrast, the outcome in UIR patients after CRT was excellent.

The Diagnostic Value of PSMA PET/CT in Men with Newly Diagnosed Unfavorable Intermediate-Risk Prostate Cancer.

Our objective was to determine the diagnostic value of prostate-specific membrane antigen (PSMA) PET/CT in staging men with newly diagnosed unfavorable intermediate-risk prostate cancer (PCa). Methods: Patients with newly diagnosed unfavorable intermediate-risk PCa, in whom PSMA PET/CT was performed as a primary staging modality, were retrospectively studied. PSMA PET/CT was performed at several diagnostic centers and reported by expert nuclear medicine physicians within 2 high-volume PCa centers. A multivariate logistic regression analysis, taking into account clinical, biochemical, pathologic, and radiologic variables, was performed to identify potential independent predictors for metastatic disease on PSMA PET/CT. Results: In total, 396 men with newly diagnosed unfavorable intermediate-risk PCa were studied. Metastatic disease was observed in 37 (9.3%) men, of whom 29 (7.3%) had molecular imaging locoregional lymph node metastases (miN1) and 16 (4.0%) had distant metastases (miM1). A radiologic tumor stage of at least T3 on MRI (odds ratio, 2.72 [95% CI, 1.27-5.83]; P = 0.01) and more than 50% positive prostate biopsies (odds ratio, 3.87 [95% CI, 1.74-8.62]; P = 0.001) were found to be independently associated with metastatic disease on PSMA PET/CT. Conclusion: Given that metastatic disease was observed in nearly 1 in 10 men with newly diagnosed unfavorable intermediate-risk PCa, PSMA PET/CT is considered to be of diagnostic value within this population. Further stratification using the radiologic tumor stage and the percentage of positive prostate biopsies could aid in identifying those patients at risk of having metastatic disease on PSMA PET/CT.

Assessing the impact of brachytherapy boost and androgen deprivation therapy on survival outcomes for patients with unfavorable intermediate-risk prostate cancer patients treated with external beam radiotherapy.

BACKGROUND: Current recommendations regarding radiotherapy treatment for unfavorable intermediate-risk prostate cancer (UIR-PCa) include external beam radiotherapy (EBRT) ± brachytherapy boost (BT) ± androgen deprivation therapy (ADT). The ideal radiotherapy treatment approach for UIR-PCa has not been well-defined. We hypothesized that EBRT+BT±ADT is associated with improved overall survival (OS) relative to EBRT±ADT in men with UIR-PCa. MATERIALS AND METHODS: The National Cancer Database (NCDB) was used to retrospectively identify 32,246 men diagnosed between 2004 and 2015 with UIR-PCa who received EBRT (n = 13,265), EBRT+ADT (n = 13,123), EBRT+BT (n = 3440), or EBRT+BT+ADT (n = 2418). OS was the primary outcome. Inverse probability of treatment weighting was used to adjust for covariable imbalances and weight-adjusted multivariable analysis using Cox regression modeling was used to compare OS hazard ratios. RESULTS: Median follow-up was 60 months (range: 3-168 months). EBRT+ADT correlated with improved OS relative to EBRT alone on multivariable analysis (Hazard Ratio (HR): 0.92, [95% Confidence Interval: 0.87-0.98], p = 0.005). Compared to EBRT+ADT, EBRT+BT (HR: 0.77 [0.69-0.85], p = 3 × 10-7) and EBRT+BT+ADT (HR: 0.75 [0.67-0.83], p = 6 × 10-8) were associated with improved OS. Eight-years OS for the EBRT+ADT versus EBRT+BT+ADT was 70% and 78% (p < 0.0001), which is similar to historical clinical trials (ASCENDE-RT 9-year OS: 74% vs. 78%, p = 0.29). Relative to EBRT+BT, EBRT+BT+ADT was not associated with improved OS (HR: 0.99 [0.87-1.11], p = 0.82). CONCLUSIONS: In a large retrospective cohort, the addition of brachytherapy to EBRT correlated with improved survival in men with UIR-PCa. Men receiving EBRT+ADT+BT had improved OS relative to EBRT+ADT. The addition of ADT to EBRT, but not to EBRT+BT, correlated with improved OS.

Assessing the role of external beam radiation therapy in combination with brachytherapy versus brachytherapy alone for unfavorable intermediate-risk prostate cancer.

BACKGROUND: Definitive treatment options for unfavorable intermediate-risk prostate cancer (UIR-PCa) include external beam radiotherapy (EBRT) ± brachytherapy boost ± androgen deprivation therapy (ADT). The role of brachytherapy ± ADT in the absence of EBRT is not well defined. We hypothesized that EBRT+BT±ADT is associated with improved overall survival (OS) relative to BT±ADT for UIR-PCa. METHODS AND MATERIALS: Men with UIR-PCa diagnosed between 2004 and 2015 were identified in the National Cancer Database (NCDB). Inverse propensity of treatment weighting was used to balance covariables that influenced treatment allocation and outcomes, and propensity-weighted multivariable analysis (MVA) using Cox regression modeling was used to compare OS hazard ratios. RESULTS: A total of 11,721 men were stratified into four treatment groups: (1) BT without ADT (n = 4,535), (2) BT+ADT (n = 1,303), (3) EBRT+BT (n = 3,446), or (4) EBRT+BT+ADT (n = 2,437). Relative to patients treated with BT alone, BT+ADT (Hazard Ratio (HR): 0.86 [95% Confidence Interval (CI): 0.76-0.99], p = 0.03), EBRT+BT (HR: 0.79 [0.70-0.88], p = 0.00002), and EBRT+BT+ADT (HR: 0.76 [0.67-0.85], p = 0.000003) were associated with improved OS on MVA. Relative to BT alone, EBRT+BT correlated with improved OS on weight-adjusted MVA (HR: 0.82 [0.75-0.89], p = 0.000005). 10-year OS for BT vs. EBRT+BT was 62.4% [60.1-64.7] vs. 69.3% [67.5-71.2], respectively (p < 0.0001). CONCLUSIONS: EBRT+BT correlated with improved OS relative to BT alone in men with UIR-PCa, reaffirming current NCCN recommendations recommending EBRT+BT over BT alone. While prior studies reported no benefit to adding EBRT to BT with optimal implant dosimetry, this study suggests men benefit from EBRT in a population of variable implant quality.

Stereotactic Radiotherapy and Androgen Deprivation Therapy for Localized Prostate Cancer: A Retrospective Mono-institutional Experience.

BACKGROUND/AIM: Stereotactic radiotherapy (SRT) is an effective treatment for localized prostate cancer. However, is it not clear whether the addition of androgen deprivation therapy (ADT) to SRT is beneficial. The aim of this study was to analyze the outcomes of a series of patients treated with SRT plus ADT for localized prostate cancer. PATIENTS AND METHODS: Patients were treated with SRT with 42 Gy in 7 fractions with volumetric-modulated arc therapy plus Image Guided Radiotherapy (V-MAT IGRT) technique. ADT was administered to patients with intermediate unfavorable- and high-risk disease. Study endpoints were biochemical disease-free survival (bDFS), overall survival (OS), acute and late toxicity and patient-reported outcomes (PROs) using international prostate cancer symptoms scale (IPSS) and international index of erectile function (IIEF). RESULTS: A total of 170 consecutive patients were identified, of which 49 (28.8%) with low-risk, 15 (8.8%) with favorable intermediate-risk 76 (44.7%) with unfavorable intermediate-risk and 30 (17.6%) with high-risk class. All patients of unfavorable intermediate- and high-risk groups were administered LHRH analogue concurrently to SRT and for at least 6 months. Patients with unfavorable intermediate- and high-risk presented a 5-year bDFS of 81.7% and 76.9%, respectively. CONCLUSION: SRT consisting of 42 Gy in seven fractions with short-term ADT represents a safe and effective treatment for unfavorable intermediate and high risk prostate cancer. Our results support the need of high quality studies to test the efficacy of ADT combined with SRT for unfavorable intermediate- and high-risk localized prostate cancer.

Propensity-Weighted Survival Analysis of SBRT vs. Conventional Radiotherapy in Unfavorable Intermediate-Risk Prostate Cancer.

BACKGROUND: Prostate stereotactic body radiotherapy (SBRT), which delivers high-dose precision treatment in ≤5 fractions, is a shorter, more convenient, and less expensive alternative to conventionally fractionated radiotherapy (CRFT; ∼44 fractions) or moderately hypofractionated radiotherapy (MFRT; 20-28 fractions). SBRT has not been widely adopted but may have radiobiologic advantages over CFRT/MFRT. We hypothesized that SBRT would be associated with improved overall survival (OS) versus CFRT or MFRT ± androgen deprivation therapy (ADT) for unfavorable-intermediate-risk prostate cancer (UIR-PCa). METHODS: Men with UIR-PCa treated with SBRT (35-40Gy in ≤5 fractions) or biologically equivalent doses of CFRT (72-86.4Gy in 1.8-2.0Gy/fraction) or MRFT (≥60Gy in 2.4-3.2Gy/fraction; biologically effective doses ≥120) were identified in the National Cancer Database (NCDB). Unweighted and propensity-weighted multivariable Cox analysis (MVA) was used to compare OS hazard ratios. RESULTS: Of 28,028 men with UIR-PCa who received CFRT with (n = 12,872) or without ADT (n = 12,984); MFRT with (n = 251) or without ADT (n = 281); and SBRT with (n = 212) or without ADT (n = 1,428) were identified. Relative to CFRT without ADT, CFRT+ ADT (HR 0.92, 95% CI 0.87-0.97, P = .002) and SBRT without ADT (HR 0.74, 95% CI 0.61-0.89, P = .002) were both associated with improved OS on MVA. Relative to CFRT+ADT, SBRT without ADT correlated with improved OS on MVA (HR:0.81, 95% CI 0.67-0.99, P = .04). Propensity-weighted MVA demonstrated that SBRT (HR:0.80, 95% CI 0.65-0.98, P = .036) and ADT (HR:0.91, 95% CI 0.86-0.97, P = .002) correlated with improved OS. SBRT was not associated with improved OS versus MFRT. CONCLUSION: SBRT, which offers a cheaper and shorter treatment course that mitigates COVID-19 exposure, was associated with improved OS versus CFRT for UIR-PCa. These results confirm guideline-based recommendations that SBRT is a viable option for UIR prostate cancer. The results from this large retrospective study require further validation in clinical trials.

Oncologic Outcomes of Radical Prostatectomy and High-Dose Intensity-Modulated Radiotherapy with Androgen-Deprivation Therapy for Relatively Young Patients with Unfavorable Intermediate-Risk Prostate Adenocarcinoma.

PURPOSE: To estimate the oncologic outcomes of radical prostatectomy (RP) and high-dose intensity-modulated radiotherapy (IMRT) with short-term androgen-deprivation therapy (ADT) in relatively young men with unfavorable intermediate-risk prostate cancer, as defined by the National Comprehensive Cancer Network (NCCN-UIR-PC). PATIENTS AND METHODS: We enrolled relatively young men (≤65 years) from the Taiwan Cancer Registry who had been diagnosed as having NCCN-UIR-PC and who had received RP or high-dose IMRT (at least ≥72 Gy) with short-term ADT (4-6 months). After propensity score matching of the confounders, Cox proportional regression was used to model the time from the index date (i.e., date of diagnosis) to all-cause death, biochemical failure (BF), locoregional recurrence (LRR), and distant metastasis (DM). RESULTS: The corresponding adjusted hazard ratios (95% confidence intervals) of the risk of all-cause death, BF, LRR, and DM were 2.76 (1.36-5.60, p = 0.0050), 2.74 (1.72-4.84, p < 0.0001), 1.28 (1.09-1.90, p = 0.0324), and 2.11 (1.40-4.88, p = 0.0052), respectively. CONCLUSIONS: RP is superior to high-dose IMRT with short-term ADT in terms of oncologic outcomes for relatively young men with UIR-PC.

Improving the Stratification of Patients With Intermediate-risk Prostate Cancer.

BACKGROUND: Intermediate-risk prostate cancer (IR PCa) phenotypes may vary from favorable to unfavorable. National Comprehensive Cancer Network (NCCN) criteria help distinguish between those groups. We studied and attempted to improve this stratification. PATIENTS AND METHODS: A total of 4048 (NCCN favorable: 2015 [49.8%] vs. unfavorable 2033 [50.2%]) patients with IR PCa treated with radical prostatectomy were abstracted from an institutional database (2000-2018). Multivariable logistic regression models predicting upstaging and/or upgrading (Gleason Grade Group [GGG] IV-V and/or ≥ pT3 or pN1) in IR PCa were developed, validated, and directly compared with the NCCN IR PCa stratification. RESULTS: All 4048 patients were randomly divided between development (n = 2024; 50.0%) and validation cohorts (n = 2024; 50.0%). The development cohort was used to fit basic (age, prostate-specific antigen, clinical T stage, biopsy GGG, and percentage of positive cores [all P < .001]) and extended models (age, prostate-specific antigen, clinical T stage, biopsy GGG, prostate volume, and percentage of tumor within all biopsy cores [all P < .001]). In the validation cohort, the basic and the extended models were, respectively, 71.4% and 74.7% accurate in predicting upstaging and/or upgrading versus 66.8% for the NCCN IR PCa stratification. Both models outperformed NCCN IR PCa stratification in calibration and decision curve analyses (DCA). Use of NCCN IR PCa stratification would have misclassified 20.1% of patients with ≥ pT3 or pN1 and/or GGG IV to V versus 18.3% and 16.4% who were misclassified using the basic or the extended model, respectively. CONCLUSION: Both newly developed and validated models better discriminate upstaging and/or upgrading risk than the NCCN IR PCa stratification.