Long-Term Analysis of NRG Oncology RTOG 0415: A Randomized Phase III Noninferiority Study Comparing Two Fractionation Schedules in Patients With Low-Risk Prostate Cancer

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.NRG Oncology RTOG 0415 is a randomized phase III noninferiority (NI) clinical trial comparing conventional fractionation (73.8 Gy in 41 fractions) radiotherapy (C-RT) with hypofractionation (H-RT; 70 Gy in 28) in patients with low-risk prostate cancer. The study included 1,092 protocol-eligible patients initially reported in 2016 with a median follow-up of 5.8 years. Updated results with median follow-up of 12.8 years are now presented. The estimated 12-year disease-free survival (DFS) is 56.1% (95% CI, 51.5 to 60.5) for C-RT and 61.8% (95% CI, 57.2 to 66.0) for H-RT. The DFS hazard ratio (H-RT/C-RT) is 0.85 (95% CI, 0.71 to 1.03), confirming NI (P < .001). Twelve-year cumulative incidence of biochemical failure (BF) was 17.0% (95% CI, 13.8 to 20.5) for C-RT and 9.9% (95% CI, 7.5 to 12.6) for H-RT. The HR (H-RT/C-RT) comparing biochemical recurrence between the two arms was 0.55 (95% CI, 0.39 to 0.78). Late grade ≥3 GI adverse event (AE) incidence is 3.2% (C-RT) versus 4.4% (H-RT), with relative risk (RR) for H-RT versus C-RT 1.39 (95% CI, 0.75 to 2.55). Late grade ≥3 genitourinary (GU) AE incidence is 3.4% (C-RT) versus 4.2% (H-RT), RR 1.26 (95% CI, 0.69 to 2.30). Long-term DFS is noninferior with H-RT compared with C-RT. BF is less with H-RT. No significant differences in late grade ≥3 GI/GU AEs were observed between assignments (ClinicalTrials.gov identifier: NCT00331773).

Radiation technique and outcomes following moderately hypofractionated treatment of low risk prostate cancer: a secondary analysis of RTOG 0415

BACKGROUND

While moderately hypofractionated radiotherapy (MHRT) for prostate cancer (PC) is commonly delivered by intensity modulated radiation therapy, IMRT has not been prospectively compared to three-dimensional conformal radiotherapy (3D-CRT) in this context. We conducted a secondary analysis of the phase III RTOG 0415 trial comparing survival and toxicity outcomes for low-risk PC following MHRT with IMRT versus 3D-CRT.

METHODS

RTOG 0415 was a phase III, non-inferiority trial randomizing low-risk PC patients to either MHRT or conventionally fractionated radiation with stratification by RT technique. A secondary analysis for differences in overall survival (OS), biochemical recurrence free survival (BRFS), or toxicity by EPIC scores and Common Terminology Criteria for Adverse Events (CTCAE) was performed.

RESULTS

1079 patients received the allocated intervention with a median follow up of 5.8 years. 79.1% of patients were treated with IMRT and radiation technique was balanced between arms. Across all patients, RT technique was not associated with significant differences in BRFS, OS, or rates of acute and late toxicities. For patients completing MHRT, there was a difference in the late GU toxicity distribution between 3D-CRT and IMRT but no difference in late grade 2 or greater GU or GI toxicity. Stratifying patients by RT technique and fractionation, no significant differences were observed in the minimal clinically important difference (MCID) in EPIC urinary and bowel scores following RT.

CONCLUSIONS

RT technique did not impact clinical outcomes following MHRT for low-risk PC. Despite different late GU toxicity distributions in patients treated with MHRT by IMRT or 3D-CRT, there was no difference in late Grade 2 or greater GU or GI toxicity or patient reported toxicity. Increases in late GU and GI toxicity following MHRT compared to CFRT, as demonstrated in the initial publication of RTOG 0415, do not appear related to a 3D-CRT treatment technique.

Updated 5-year results for short course abiraterone acetate and LHRH agonist for unfavorable intermediate and favorable high-risk prostate cancer

Combined androgen deprivation therapy (ADT) and radiotherapy (RT) improves outcomes for intermediate and high-risk prostate cancer. Treatment intensification with abiraterone acetate/prednisone (AAP) provides additional benefit for high-risk disease. We previously reported 3-year outcomes of a single-arm prospective multicenter trial (AbiRT trial) of 33 patients with unfavorable intermediate risk (UIR) and favorable high risk (FHR) prostate cancer undergoing short course, combination therapy with ADT, AAP, and RT. Here we report the final analysis demonstrating a high rate of testosterone recovery (97%) and excellent biochemical progression-free survival (97%) at 5 years. These data support comparative prospective studies of shorter, more potent ADT courses in favorable high-risk prostate cancer.

Long-Term Follow-Up Analysis of NRG Oncology RTOG 0415: A Randomized Phase III Non-Inferiority Study Comparing Two Fractionation Schedules in Patients with Favorable-Risk Prostate Cancer

PURPOSE/OBJECTIVE(S)

To assess whether the efficacy of a hypofractionated (H) schedule is no worse than a conventional (C) schedule in men with low-risk prostate cancer.

MATERIALS/METHODS

Accrual began April 2006 and ended in December 2009. 1115 men with favorable-risk prostate cancer were randomly assigned 1:1 to a conventional (C) schedule (73.8 Gy in 41 fractions over 8.2 weeks) or to a hypofractionated (H) schedule (70 Gy in 28 fractions over 5.6 weeks). The trial was designed to establish with 90% power and alpha = 0.05 that (H) results in 5-year disease-free survival (DFS) that is not lower than (C) by more than 7% (hazard ratio (HR) < 1.52). Protocol specified secondary endpoints evaluated for noninferiority include: biochemical recurrence (BR), local progression, disease-specific survival, and overall survival.

RESULTS

One thousand ninety-two protocol eligible men were analyzed: 542 to C and 550 to H. Median follow-up is 12.75 years. Baseline characteristics were not different according to treatment arm. The estimated 12-year DFS is 56.1% (95% CI 51.5, 60.5) in the C arm and 61.8% (57.2, 66.0) in the H arm. The DFS hazard ratio (H/C) is 0.85 (0.71-1.03), confirming non-inferiority (p<0.001). Twelve-year cumulative incidence of biochemical recurrence (BR) was 17.0% (CI 13.8, 20.5) in the C-RT and 9.9% (CI 7.5, 12.6) in the H-RT arm; (HR = 0.56, (0.40-0.78) suggesting improved efficacy with H. Additional pre-specified secondary endpoints were non-inferior Late Grade ≥ 3 GI toxicity is 3.2% (C) vs. 4.4% (H), Relative risk (RR) for H vs. C 1.39 (CI 0.75, 2.55) Late Grade ≥ 3 GU toxicity is 3.4% (C) vs. 4.2% (H), RR = 1.26 (CI 0.69, 2.30).

CONCLUSION

In men with favorable-risk prostate cancer, long-term disease-free survival is non-inferior with 70 Gy in 28 fractions compared to 73.8 Gy in 41 fractions. The risk of BR is reduced with moderate hypofractionation. No differences in late Grade ≥3 GI/GU toxicity were observed between the arms. (ClinicalTrials.gov identifier: NCT00331773).

Toxicity and Outcomes of Moderately Hypofractionated Radiation for Prostate Cancer With Seminal Vesicle Involvement

Purpose

The aim of this study was to assess the toxicity and outcomes following treatment of prostate cancer with seminal vesicle involvement (SVI) evident on magnetic resonance imaging or clinical examination with moderately hypofractionated radiation therapy (MHRT).

Methods and Materials

Forty-one patients treated with MHRT to the prostate and 1 or both seminal vesicles from 2013 to 2021 at a single institution were identified and propensity score matched to 82 patients treated during the same period with prescription dose given to the prostate alone. Dosimetry of the planning target volume, bladder, and rectum were compared. Urinary and bowel toxicity were scored by National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0. Clinical outcomes including freedom from biochemical recurrence, prostate cancer-specific survival, and overall survival were assessed.

Results

Of the 41 patients identified with SVI, 26.8% had SVI by clinical examination and 95.1% had high-risk prostate cancer. Compared with the cohort without SVI, treatment plans to include SVI had a larger planning target volume (152.2 vs 109.9 cc; P < .001), maximum point dose (107.9% vs 105.8%; P < .001), and volume receiving 100% of the prescription dose (143.1 vs 95.9 cc; P < .001). No difference in bladder dosimetric variables between cohorts was observed, but there was an increase in the rectal maximum point dose (103.9% vs 102.8%; P = .030) and rectal volume receiving 100% of the prescription dose (1.8 vs 1.2 cc; P = .016). Despite these differences, there was no difference in the cumulative incidence of grade 2+ urinary (hazard ratio [HR], 0.73; 95% CI, 0.39-1.35; P = .31) or bowel (HR, 0.35; 95% CI, 0.04-3.03; P = .34) toxicity. Freedom from biochemical recurrence (HR, 0.47; 95% CI, 0.16-1.38; P = .17), prostate cancer-specific survival (HR, 0.31; 95% CI, 0.04-2.49; P = .31), and overall survival (HR, 0.35; 95% CI, 0.10-1.16; P = .09) also did not differ with or without SVI, respectively.

Conclusions

Treatment of SVI to prescription dose with MHRT for localized prostate cancer does not increase bowel or urinary toxicity. Similar clinical outcomes were also observed with or without SVI.

Neighborhood Deprivation and Rurality Associated With Patient-Reported Outcomes and Survival in Men With Prostate Cancer in NRG Oncology RTOG 0415

PURPOSE

Rurality and neighborhood deprivation can contribute to poor patient-reported outcomes, which have not been systematically evaluated in patients with specific cancers in national trials. Our objective was to examine the effect of rurality and neighborhood socioeconomic and environmental deprivation on patient-reported outcomes and survival in men with prostate cancer in NRG Oncology RTOG 0415.

METHODS AND MATERIALS

Data from men with prostate cancer in trial NRG Oncology RTOG 0415 were analyzed; 1,092 men were randomized to receive conventional radiation therapy or hypofractionated radiation therapy. Rurality was categorized as urban or rural. Neighborhood deprivation was assessed using the area deprivation index and air pollution indicators (nitrogen dioxide and particulate matter with a diameter less than 2.5 micrometers) via patient ZIP codes. Expanded Prostate Cancer Index Composite measured cancer-specific quality of life. The Hopkins symptom checklist measured anxiety and depression. EuroQoL-5 Dimension assessed general health.

RESULTS

We analyzed 751 patients in trial NRG Oncology RTOG 0415. At baseline, patients from the most deprived neighborhoods had worse bowel (P = .011), worse sexual (P = .042), and worse hormonal (P = .015) scores; patients from the most deprived areas had worse self-care (P = .04) and more pain (P = .047); and patients from rural areas had worse urinary (P = .03) and sexual (P = .003) scores versus patients from urban areas. Longitudinal analyses showed that the 25% most deprived areas (P = .004) and rural areas (P = .002) were associated with worse EuroQoL-5 Dimension visual analog scale score. Patients from urban areas (hazard ratio, 1.81; P = .033) and the 75% less-deprived neighborhoods (hazard ratio, 0.68; P = .053) showed relative decrease in risk of recurrence or death (disease-free survival).

CONCLUSIONS

Patients with prostate cancer from the most deprived neighborhoods and rural areas had low quality of life at baseline, poor general health longitudinally, and worse disease-free survival. Interventions should screen populations from deprived neighborhoods and rural areas to improve patient access to supportive care services.

Second generation anti-androgens and androgen deprivation therapy with radiation therapy in the definitive management of high-risk prostate cancer

BACKGROUND

Evolving data suggest that men with high-risk localized prostate cancer may benefit from more potent androgen receptor inhibition in the context of curative intent radiotherapy. Recently updated American Society for Clinical Oncology (ASCO) evidence-based guidelines and the National Comprehensive Cancer Network (NCCN) Guidelines have updated recommendations for the consideration of adding second generation anti-androgens to androgen deprivation therapy (ADT) in men receiving radiation therapy (RT) for noncastrate locally advanced high and very high risk nonmetastatic or node positive prostate cancer.

METHODS AND RESULTS

We conducted a comprehensive review of existing published and abstract presented evidence behind RT with ADT for the definitive management of high-risk prostate cancer, particularly focused on the current phase II and III trial evidence for the addition of second generation anti-androgens to ADT in definitive RT treatment of high-risk prostate cancer and specifically focused on the recent STAMPEDE trial results with abiraterone acetate. We review the biological mechanisms in which second generation anti-androgens may help mitigate ADT resistance and provide radiosensitization through inhibition of DNA repair. Finally, we discuss ongoing clinical trials of potent androgen receptor (AR) inhibitors with ADT in this non-metastatic high-risk radiotherapy setting that may inform on future treatment guidelines.

CONCLUSIONS

Recent data suggest an overall survival benefit as well as increased probabilities of disease free and metastasis free survival in men with high and very high-risk localized, node positive, and oligometastatic hormone sensitive prostate cancer with abiraterone acetate and prednisone and support the use of potent AR inhibitors in this setting after informed decision making.

The Influence of the Pretreatment Immune State on Response to Radiation Therapy in High-Risk Prostate Cancer: A Validation Study From NRG/RTOG 0521

PURPOSE

The immunoinflammatory state has been shown to be associated with poor outcomes after radiation therapy (RT). We conducted an a priori designed validation study using serum specimens from Radiation Therapy Oncology Group (RTOG) 0521. It was hypothesized the pretreatment inflammatory state would correlate with clinical outcomes.

METHODS AND MATERIALS

Patients on RTOG 0521 had serum banked for biomarker validation. This study was designed to validate previous findings showing an association between elevations in C-reactive protein (CRP) and shorter biochemical disease free survival (bDFS). CRP levels were measured in pretreatment samples. An exploratory panel of related cytokines was also measured including: monocyte chemotactic protein-1, granulocyte-macrophage colony-stimulating factor, interferon-γ, interleukin (IL)-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IL-17A, IL-23, and tumor necrosis factor. The primary endpoint examined was bDFS. Additional exploratory endpoints included overall survival, distant metastases, and toxicity events attributed to RT.

RESULTS

Two hundred and two patients in RTOG/NRG 0521 had serum samples available. Median age was 66 years (48-83), and 90% of patients were White. There was not an association between CRP and bDFS (adjusted hazard ratio [HR], 1.07 per 1 log increase in CRP; 95% confidence interval, 0.83-1.38; P = .60). In the exploratory, unplanned analysis, pretreatment IL-10 was significantly associated with worse bDFS (adjusted HR, 1.61 per log increase; P = .0027) and distant metastases (HR, 1.55 per log increase; P = .028). The association of IL-10 with bDFS was maintained on a multiplicity adjustment. The exploratory analyses of pretreatment levels of interferon-γ, IL-1b, IL-2, IL-13, IL-23 were negatively associated with grade 2 or higher pollakiuria (adjusted odds ratio, 0.64, 0.65, 0.71, 0.72, and 0.74, respectively, all P < .05), and IL-6 was negatively associated with grade 2 or higher erectile dysfunction (odds ratio, 0.62; P = .027).

CONCLUSIONS

Pretreatment CRP was not associated with a poorer bDFS after RT. In a hypothesis- generating analysis, higher baseline levels of IL-10 were associated with lower rates of bDFS. These findings require additional prospective evaluation.

Impact of Race on Outcomes of High-Risk Patients With Prostate Cancer Treated With Moderately Hypofractionated Radiotherapy in an Equal Access Setting

BACKGROUND

Moderately hypofractionated radiotherapy (MHRT) is an accepted treatment for localized prostate cancer; however, limited MHRT data address high-risk prostate cancer (HRPC) and/or African American patients. We report clinical outcomes and toxicity profiles for individuals with HRPC treated in an equal access system.

METHODS

We identified patients with HRPC treated with MHRT at a US Department of Veterans Affairs referral center. Exclusion criteria included < 12 months follow-up and elective nodal irradiation. MHRT included 70 Gy over 28 fractions or 60 Gy over 20 fractions. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicities were graded using Common Terminology Criteria for Adverse Events, version 5.0. Clinical endpoints, including biochemical recurrence-free survival (BRFS), distant metastases-free survival (DMFS), overall survival (OS), and prostate cancer-specific survival (PCSS) were estimated using Kaplan-Meier methods. Clinical outcomes, acute toxicity, and late toxicity-free survival were compared between African American and White patients with logistic regression and log-rank testing.

RESULTS

Between November 2008 and August 2018, 143 patients with HRPC were treated with MHRT and followed for a median of 38.5 months; 82 (57%) were African American and 61 were White patients. Concurrent androgen deprivation therapy (ADT) was provided for 138 (97%) patients for a median duration of 24 months. No significant differences between African American and White patients were observed for 5-year OS (73% [95% CI, 58%-83%] vs 77% [95% CI, 60%-97%]; P = .55), PCSS (90% [95% CI, 79%-95%] vs 87% [95 % CI, 70%-95%]; P = .57), DMFS (91% [95% CI, 80%-96%] vs 81% [95% CI, 62%-91%]; P = .55), or BRFS (83% [95% CI, 70%-91%] vs 71% [95% CI, 53%-82%]; P = .57), respectively. Rates of acute grade 3+ GU and GI were low overall (4% and 1%, respectively). Late toxicities were similarly favorable with no significant differences by race.

CONCLUSIONS

Individuals with HRPC treated with MHRT in an equal access setting demonstrated favorable clinical outcomes that did not differ by race, alongside acceptable rates of acute and late toxicities.

Methodological Comparison of Mapping the Expanded Prostate Cancer Index Composite to EuroQoL-5D-3L Using Cross-Sectional and Longitudinal Data: Secondary Analysis of NRG/RTOG 0415

PURPOSE

To compare the predictive ability of mapping algorithms derived using cross-sectional and longitudinal data.

METHODS

This methodological assessment used data from a randomized controlled noninferiority trial of patients with low-risk prostate cancer, conducted by NRG Oncology (ClinicalTrials.gov identifier: NCT00331773), which examined the efficacy of conventional schedule versus hypofractionated radiation therapy (three-dimensional conformal external beam radiation therapy/IMRT). Health-related quality-of-life data were collected using the Expanded Prostate Cancer Index Composite (EPIC), and health utilities were obtained using EuroQOL-5D-3L (EQ-5D) at baseline and 6, 12, 24, and 60 months postintervention. Mapping algorithms were estimated using ordinary least squares regression models through five-fold cross-validation in baseline cross-sectional data and combined longitudinal data from all assessment periods; random effects specifications were also estimated in longitudinal data. Predictive performance was compared using root mean square error. Longitudinal predictive ability of models obtained using baseline data was examined using mean absolute differences in the reported and predicted utilities.

RESULTS

A total of 267 (and 199) patients in the estimation sample had complete EQ-5D and EPIC domain (and subdomain) data at baseline and at all subsequent assessments. Ordinary least squares models using combined data showed better predictive ability (lowest root mean square error) in the validation phase for algorithms with EPIC domain/subdomain data alone, whereas models using baseline data outperformed other specifications in the validation phase when patient covariates were also modeled. The mean absolute differences were lower for models using EPIC subdomain data compared with EPIC domain data and generally decreased as the time of assessment increased.

CONCLUSION

Overall, mapping algorithms obtained using baseline cross-sectional data showed the best predictive performance. Furthermore, these models demonstrated satisfactory longitudinal predictive ability.

Radiation technique and outcomes following moderately hypofractionated treatment of low risk prostate cancer: A secondary analysis of the NRG oncology RTOG 0415 randomized clinical trial

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Background: While intensity-modulated radiotherapy (IMRT) is commonly used to deliver moderately hypofractionated radiotherapy (MHRT) for prostate cancer (PC), IMRT has not been prospectively compared to three-dimensional conformal radiotherapy (3D-CRT) in the context of MHRT. This secondary analysis of the phase III RTOG 0415 trial compares survival outcomes and toxicity across RT technique between IMRT and 3D-CRT for low-risk PC. Methods: The phase III, non-inferiority trial RTOG 0415 randomized patients with low risk PC to either MHRT (70Gy at 2.5Gy/fraction) or conventionally fractionated radiation (CFRT; 73.8Gy at 1.8Gy/fraction) with stratification by RT technique. A secondary analysis for differences in overall (OS), biochemical recurrence free survival (BRFS), or toxicity by EPIC scores and Common Terminology Criteria for Adverse Events (CTCAE) was performed. For patient and tumor characteristics, continuous data were compared with Wilcoxon rank sum test and categorical data with Chi-squared test, as appropriate. Rates of BRFS and overall survival (OS) were calculated using the Kaplan-Meier method. Results: 1079 patients received the allocated intervention with a median follow up of 5.8 years. RT technique was balanced between treatment arms, with 79.1% of patients receiving IMRT. RT protocol compliance was > 95% for both IMRT and 3D-CRT. There were no significant differences in BRFS between patients treated with 3D-CRT versus IMRT for all patients (p = 0.33), those randomized to CFRT (p = 0.78), or those randomized to MHRT (p = 0.24). Overall survival did not differ by RT technique as well. For all patients, there was no difference in acute and late GI and GU toxicity rates across RT technique. For patients treated with MHRT, late grade 2 GU toxicity was more common with IMRT than 3D-CRT (31.3% vs 23.4%; p = 0.004). On logistic regression analysis, only poor baseline urinary function, defined as an EPIC score of 90 or below, correlated with acute (p < 0.001) or late (p < 0.001) GU toxicity. Baseline bowel function did not correlate to GI toxicity. Conclusions: RT technique did not impact survival outcomes or toxicity rates following MHRT for low risk PC. Higher rates of late CTCAE grade 2+ GU and GI toxicity observed within the RTOG 0415 MHRT arm were not disproportionally observed following 3D-CRT than IMRT. These data highlight the need for careful consideration of target delineation and normal tissue constraints in the selection and delivery of appropriate RT technique.

Comparison of Response to Definitive Radiotherapy for Localized Prostate Cancer in Black and White Men: A Meta-analysis

IMPORTANCE

Black men have a 2-fold increased risk of dying from prostate cancer compared with White men. However, race-specific differences in response to initial treatment remain unknown.

OBJECTIVE

To compare overall and treatment-specific outcomes of Black and White men with localized prostate cancer receiving definitive radiotherapy (RT).

DATA SOURCES

A systematic search was performed of relevant published randomized clinical trials conducted by the NRG Oncology/Radiation Therapy Oncology Group between January 1, 1990, and December 31, 2010. This meta-analysis was performed from July 1, 2019, to July 1, 2021.

STUDY SELECTION

Randomized clinical trials of definitive RT for patients with localized prostate cancer comprising a substantial number of Black men (self-identified race) enrolled that reported on treatment-specific and overall outcomes.

DATA EXTRACTION AND SYNTHESIS

Individual patient data were obtained from 7 NRG Oncology/Radiation Therapy Oncology Group randomized clinical trials evaluating definitive RT with or without short- or long-term androgen deprivation therapy. Unadjusted Fine-Gray competing risk models, with death as a competing risk, were developed to evaluate the cumulative incidences of end points. Cox proportional hazards models were used to evaluate differences in all-cause mortality and the composite outcome of distant metastasis (DM) or death. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was followed.

MAIN OUTCOMES AND MEASURES

Subdistribution hazard ratios (sHRs) of biochemical recurrence (BCR), DM, and prostate cancer-specific mortality (PCSM).

RESULTS

A total of 8814 patients (1630 [18.5%] Black and 7184 [81.5%] White) were included; mean (SD) age was 69.1 (6.8) years. Median follow-up was 10.6 (IQR, 8.0-17.8) years for surviving patients. At enrollment, Black men were more likely to have high-risk disease features. However, even without adjustment, Black men were less likely to experience BCR (sHR, 0.88; 95% CI, 0.58-0.91), DM (sHR, 0.72; 95% CI, 0.58-0.91), or PCSM (sHR, 0.72; 95% CI, 0.54-0.97). No significant differences in all-cause mortality were identified (HR, 0.99; 95% CI, 0.92-1.07). Upon adjustment, Black race remained significantly associated with improved BCR (adjusted sHR, 0.79; 95% CI, 0.72-0.88; P < .001), DM (adjusted sHR, 0.69; 95% CI, 0.55-0.87; P = .002), and PCSM (adjusted sHR, 0.68; 95% CI, 0.50-0.93; P = .01).

CONCLUSIONS AND RELEVANCE

The findings of this meta-analysis suggest that Black men enrolled in randomized clinical trials present with more aggressive disease but have better BCR, DM, and PCSM with definitive RT compared with White men, suggesting that other determinants of outcome, such as access to care, are important factors of achieving racial equity.

Mapping expanded prostate cancer index composite to EQ5D utilities to inform economic evaluations in prostate cancer: Secondary analysis of NRG/RTOG 0415

PURPOSE

The Expanded Prostate Cancer Index Composite (EPIC) is the most commonly used patient reported outcome (PRO) tool in prostate cancer (PC) clinical trials, but health utilities associated with the different health states assessed with this tool are unknown, limiting our ability to perform cost-utility analyses. This study aimed to map EPIC tool to EuroQoL-5D-3L (EQ5D) to generate EQ5D health utilities.

METHODS AND MATERIALS

This is a secondary analysis of a prospective, randomized non-inferiority clinical trial, conducted between 04/2006 and 12/2009 at cancer centers across the United States, Canada, and Switzerland. Eligible patients included men >18 years with a known diagnosis of low-risk PC. Patient HRQoL data were collected using EPIC and health utilities were obtained using EQ5D. Data were divided into an estimation sample (n = 765, 70%) and a validation sample (n = 327, 30%). The mapping algorithms that capture the relationship between the instruments were estimated using ordinary least squares (OLS), Tobit, and two-part models. Five-fold cross-validation (in-sample) was used to compare the predictive performance of the estimated models. Final models were selected based on root mean square error (RMSE).

RESULTS

A total of 565 patients in the estimation sample had complete information on both EPIC and EQ5D questionnaires at baseline. Mean observed EQ5D utility was 0.90±0.13 (range: 0.28-1) with 55% of patients in full health. OLS models outperformed their counterpart Tobit and two-part models for all pre-determined model specifications. The best model fit was: "EQ5D utility = 0.248541 + 0.000748*(Urinary Function) + 0.001134*(Urinary Bother) + 0.000968*(Hormonal Function) + 0.004404*(Hormonal Bother)- 0.376487*(Zubrod) + 0.003562*(Urinary Function*Zubrod)"; RMSE was 0.10462.

CONCLUSIONS

This is the first study to identify a comprehensive set of mapping algorithms to generate EQ5D utilities from EPIC domain/ sub-domain scores. The study results will help estimate quality-adjusted life-years in PC economic evaluations.

Longitudinal predictive ability of mapping algorithms: Secondary analysis of NRG Oncology/RTOG 0415

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Background: Mapping algorithms informing economic evaluations are often derived using baseline data from clinical trials. It is unclear if these algorithms can predict health utilities accurately in post-intervention data. Thus, this study examines the longitudinal predictive ability of mapping algorithms derived from baseline trial data and explores the factors associated with prediction errors. Methods: This methodological study utilized data from an international, multicenter, randomized controlled trial of patients with low-risk prostate cancer (PC), conducted by NRG Oncology (NCT00331773). In addition to patient demographic and clinical data, this study utilized PRO data collected at baseline and 6, 12 and 24 months post-intervention. The Expanded Prostate Cancer Index Composite (EPIC) questionnaire measures health-related quality-of-life (HRQoL) and has four domains (urinary, sexual, hormonal, and bowel) and two subdomains per domain (function and bother); EuroQOL-5D-3L (EQ5D) captures health utilities. Ordinary Least Squares (OLS) regression models were used to map EPIC scores to EQ5D utilities in the baseline data through 5-fold cross-validation. Predictive performance was tested in the post-intervention data; predicted and reported utilities were compared using t-tests, and the absolute prediction error was modeled using fixed effects, as a function of baseline demographic and clinical covariates, as well as observed and predicted EQ5D utilities. Results: A total of 267 (199) patients had complete EQ5D and EPIC domain (or subdomain) data at baseline and all subsequent assessments. In the EPIC domain sample, mean ± standard deviation observed EQ5D utility was 0.90±0.13 at baseline, 0.92±0.11 at 6 months, 0.90±0.13 at 12 months and 0.89±0.14 at 24 months. Mean absolute differences (MDs) between reported and predicted were lower for models using EPIC subdomain data compared to EPIC domain data, and generally decreased as the time of assessment increased. The mapping functions over-predicted utilities for patients in perfect health while the prediction errors were increasingly negative for lower reported EQ5D scores. According to the fixed effects model for EPIC domain data, lower observed and predicted baseline EQ5D scores, and time of assessment were significant predictors of the absolute prediction error; for EPIC subdomain data, lower observed and predicted baseline EQ5D scores, hormonal bother and function, and bowel function significantly predicted the absolute prediction error. Conclusions: This study is the first to demonstrate the longitudinal validity of EPIC questionnaire, and builds upon existing research on longitudinal validity of mapping functions. The low MDs in prediction errors in post-intervention data indicate that the mapping functions are sensitive to treatment effect, thereby increasing confidence in their use in economic evaluations in PC.

Implementation and Impact of a Risk-Stratified Prostate Cancer Screening Algorithm as a Clinical Decision Support Tool in a Primary Care Network

BACKGROUND

Implementation methods of risk-stratified cancer screening guidance throughout a health care system remains understudied.

OBJECTIVE

Conduct a preliminary analysis of the implementation of a risk-stratified prostate cancer screening algorithm in a single health care system.

DESIGN

Comparison of men seen pre-implementation (2/1/2016-2/1/2017) vs. post-implementation (2/2/2017-2/21/2018).

PARTICIPANTS

Men, aged 40-75 years, without a history of prostate cancer, who were seen by a primary care provider.

INTERVENTIONS

The algorithm was integrated into two components in the electronic health record (EHR): in Health Maintenance as a personalized screening reminder and in tailored messages to providers that accompanied prostate-specific antigen (PSA) results.

MAIN MEASURES

Primary outcomes: percent of men who met screening algorithm criteria; percent of men with a PSA result. Logistic repeated measures mixed models were used to test for differences in the proportion of individuals that met screening criteria in the pre- and post-implementation periods with age, race, family history, and PSA level included as covariates.

KEY RESULTS

During the pre- and post-implementation periods, 49,053 and 49,980 men, respectively, were seen across 26 clinics (20.6% African American). The proportion of men who met screening algorithm criteria increased from 49.3% (pre-implementation) to 68.0% (post-implementation) (p < 0.001); this increase was observed across all races, age groups, and primary care clinics. Importantly, the percent of men who had a PSA did not change: 55.3% pre-implementation, 55.0% post-implementation. The adjusted odds of meeting algorithm-based screening was 6.5-times higher in the post-implementation period than in the pre-implementation period (95% confidence interval, 5.97 to 7.05).

CONCLUSIONS

In this preliminary analysis, following implementation of an EHR-based algorithm, we observed a rapid change in practice with an increase in screening in higher-risk groups balanced with a decrease in screening in low-risk groups. Future efforts will evaluate costs and downstream outcomes of this strategy.

Prostate Radiotherapy With Adjuvant Androgen Deprivation Therapy (ADT) Improves Metastasis-Free Survival Compared to Neoadjuvant ADT: An Individual Patient Meta-Analysis

PURPOSE

There remains a lack of clarity regarding the influence of sequencing of androgen deprivation therapy (ADT) and radiotherapy (RT) on outcomes in prostate cancer (PCa). Herein, we evaluate the optimal sequencing of ADT with prostate-directed RT in localized PCa.

METHODS

MEDLINE (1966-2018), Embase (1982-2018), ClinicalTrials.gov, and conference proceedings (1990-2018) were searched to identify randomized trials evaluating the sequencing, but not duration, of ADT with RT. Two randomized phase III trials were identified, and individual patient data were obtained: Ottawa 0101 and NRG Oncology's Radiation Therapy Oncology Group 9413. Ottawa 0101 randomly assigned patients to neoadjuvant or concurrent versus concurrent or adjuvant short-term ADT. Radiation Therapy Oncology Group 9413, a 2 × 2 factorial trial, included a random assignment of neoadjuvant or concurrent versus adjuvant short-term ADT. The neoadjuvant or concurrent ADT arms of both trials were combined into the neoadjuvant group, and the arms receiving adjuvant ADT were combined into the adjuvant group. The primary end point of this meta-analysis was progression-free survival (PFS).

RESULTS

The median follow-up was 14.9 years. Overall, 1,065 patients were included (531 neoadjuvant and 534 adjuvant). PFS was significantly improved in the adjuvant group (15-year PFS, 29% v 36%, hazard ratio [HR], 1.25 [95% CI, 1.07 to 1.47], P = .01). Biochemical failure (subdistribution HR [sHR], 1.37 [95% CI, 1.12 to 1.68], P = .002), distant metastasis (sHR, 1.40 [95% CI, 1.00 to 1.95], P = .04), and metastasis-free survival (HR, 1.17 [95% CI, 1.00 to 1.37], P = .050) were all significantly improved in the adjuvant group. There were no differences in late grade ≥ 3 gastrointestinal (2% v 3%, P = .33) or genitourinary toxicity (5% v 5%, P = .76) between groups.

CONCLUSION

The sequencing of ADT with prostate-directed RT has significant association with long-term PFS and MFS in localized PCa. Our findings favor use of an adjuvant over a neoadjuvant approach, without any increase in long-term toxicity.

Combination of Radiation Therapy and Short-Term Androgen Blockade With Abiraterone Acetate Plus Prednisone for Men With High- and Intermediate-Risk Localized Prostate Cancer

PURPOSE

Long-term androgen-deprivation therapy (ADT) is the standard of care in combination with radiation therapy (RT) in high-risk prostate cancer (PC), despite substantial toxicity from the resulting hypogonadism. We hypothesized that a combination of more potent but shorter-term androgen inhibition in men with intermediate- or high-risk localized PC would synergize with definitive RT to provide short-term testosterone recovery and improve disease control.

METHODS AND MATERIALS

This prospective phase 2 single-arm trial enrolled men with low-volume unfavorable intermediate or high-risk localized PC. Treatment included 6 months of ADT concurrent with abiraterone acetate plus prednisone (AAP) once daily and RT to prostate and seminal vesicles. The primary endpoint was the proportion of men with an undetectable prostate-specific antigen (PSA) at 12-months; secondary objectives included biochemical progression-free survival (PFS), testosterone recovery, toxicity, and sexual and hormonal quality of life.

RESULTS

We enrolled 37 men between January 2014 and August 2016, 45% of whom were high risk. All patients had T1-2 disease and PSA < 20 ng/mL. Median follow-up is 37 months (95% confidence interval [CI], 35.7-39.1). Treatment noted 32% grade 3 toxicities related to AAP, predominantly hypertension, with no toxicities ≥G4. The rate of undetectable PSA at 12 months was 55% (95% CI, 36%-72%). With 46 months of median follow-up, 2 of 37 patients developed PSA progression (36-month PFS = 96%; 95% CI, 76%-99%), and 81% of patients recovered testosterone with a median time to recovery of 9.2 months. Hormonal or sexual function declined at 6 months with subsequent improvement by 24 months.

CONCLUSIONS

The combination of RT and 6 months of ADT and AAP demonstrated acceptable toxicity and a high rate of testosterone recovery with restoration of quality of life and excellent disease control in men with low-volume, intermediate- or high-risk localized prostate cancer. Prospective comparative studies are justified.

Short-term adjuvant versus neoadjuvant hormone therapy in localized prostate cancer: A pooled individual patient analysis of two phase III trials

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Background: The timing of systemic therapy in relation to radiotherapy (RT) is important in most malignancies. In contrast, androgen deprivation therapy (ADT) has largely been investigated in relation to its duration rather than its sequencing with RT. Herein, we conduct the first combined individual patient analysis of two phase III randomized trials to determine the optimal timing of ADT with RT in localized prostate cancer (PCa). Methods: Individual patient data was obtained from the Malone et al trial (JCO 2019), which randomized patients to receive neoadjuvant/concurrent or concurrent/adjuvant ADT for 6 months with prostate only RT. This was combined with the prostate only RT arms of RTOG 9413 that randomized patients to 4 months of neoadjuvant/concurrent or adjuvant ADT. The neoadjuvant/concurrent arms of both trials were combined into the “neoadjuvant” group, and the concurrent/adjuvant (Malone) and adjuvant arm (RTOG 9413) were combined in the “adjuvant” group. The Kaplan-Meier method was used to estimate overall survival (OS) and progression-free survival (PFS). Cumulative incidence of distant metastasis (DM), PCa-specific mortality (PCSM) and biochemical failure (BF) were calculated using the Fine-Gray method with non-PCa deaths as competing events. Late genitourinary (GU) and gastrointestinal (GI) toxicity are also reported. Results: The median follow-up was 14.9 years (yrs) and 1065 patients were included (n=531 neoadjuvant, 534 adjuvant). Groups were well balanced for all baseline characteristics. Adjuvant ADT was superior to neoadjuvant ADT in terms of BF (15yr: 33% vs 43%, HR: 1.37 (95%CI: 1.12-1.68), p=0.002), DM (15yr: 12% vs 18%, HR: 1.40 (95%CI: 1.00-1.95), p=0.04), and PFS (15yr: 36% vs 29%, HR: 1.25 (95%CI: 1.07-1.47), p=0.01). Adjuvant ADT yielded lower PCSM (15yr: 15% vs 20%, HR: 1.29 (95%CI: 0.95-1.75), p=0.10), but did not reach statistical significance. This approached statistical significance in high risk PCa (HR 1.39 (95%CI 1.00-1.93), p=0.053). OS was not significantly different between arms (15yr: 39% vs 34%, HR: 1.11 (95%CI: 0.95-1.30), p=0.20). There was no significant difference in either late grade ≥3 GI (p=0.21) or GU (p=0.98) toxicity. Conclusions: We demonstrate for the first time that sequencing of ADT with RT significantly impacts long-term oncologic outcomes in localized PCa, favoring an adjuvant rather than neoadjuvant approach, without increasing late toxicity. This data has important implications to ongoing and future clinical trial design. Clinical trial information: NCT00769548 .