Sequence of hormonal therapy and radiotherapy field size in unfavourable, localised prostate cancer (NRG/RTOG 9413): long-term results of a randomised, phase 3 trial.

BACKGROUND: The NRG/RTOG 9413 study showed that whole pelvic radiotherapy (WPRT) plus neoadjuvant hormonal therapy (NHT) improved progression-free survival in patients with intermediate-risk or high-risk localised prostate cancer compared with prostate only radiotherapy (PORT) plus NHT, WPRT plus adjuvant hormonal therapy (AHT), and PORT plus AHT. We provide a long-term update after 10 years of follow-up of the primary endpoint (progression-free survival) and report on the late toxicities of treatment. METHODS: The trial was designed as a 2 × 2 factorial study with hormonal sequencing as one stratification factor and radiation field as the other factor and tested whether NHT improved progression-free survival versus AHT, and NHT plus WPRT versus NHT plus PORT. Eligible patients had histologically confirmed, clinically localised adenocarcinoma of the prostate, an estimated risk of lymph node involvement of more than 15% and a Karnofsky performance status of more than 70, with no age limitations. Patients were randomly assigned (1:1:1:1) by permuted block randomisation to receive either NHT 2 months before and during WPRT followed by a prostate boost to 70 Gy (NHT plus WPRT group), NHT 2 months before and during PORT to 70 Gy (NHT plus PORT group), WPRT followed by 4 months of AHT (WPRT plus AHT group), or PORT followed by 4 months of AHT (PORT plus AHT group). Hormonal therapy was combined androgen suppression, consisting of goserelin acetate 3·6 mg once a month subcutaneously or leuprolide acetate 7·5 mg once a month intramuscularly, and flutamide 250 mg twice a day orally for 4 months. Randomisation was stratified by T stage, Gleason Score, and prostate-specific antigen concentration. NHT was given 2 months before radiotherapy and was continued until radiotherapy completion; AHT was given at the completion of radiotherapy for 4 months. The primary endpoint progression-free survival was analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00769548. The trial has been terminated to additional follow-up collection and this is the final analysis for this trial. FINDINGS: Between April 1, 1995, and June 1, 1999, 1322 patients were enrolled from 53 centres and randomly assigned to the four treatment groups. With a median follow-up of 8·8 years (IQR 5·07-13·84) for all patients and 14·8 years (7·18-17·4) for living patients (n=346), progression-free survival across all timepoints continued to differ significantly across the four treatment groups (p=0·002). The 10-year estimates of progression-free survival were 28·4% (95% CI 23·3-33·6) in the NHT plus WPRT group, 23·5% (18·7-28·3) in the NHT plus PORT group, 19·4% (14·9-24·0) in the WPRT plus AHT group, and 30·2% (25·0-35·4) in the PORT plus AHT group. Bladder toxicity was the most common grade 3 or worse late toxicity, affecting 18 (6%) of 316 patients in the NHT plus WPRT group, 17 (5%) of 313 in the NHT plus PORT group, 22 (7%) of 317 in the WPRT plus AHT group, and 14 (4%) of 315 in the PORT plus AHT group. Late grade 3 or worse gastrointestinal adverse events occurred in 22 (7%) of 316 patients in the NHT plus WPRT group, five (2%) of 313 in the NHT plus PORT group, ten (3%) of 317 in the WPRT plus AHT group, and seven (2%) of 315 in the PORT plus AHT group. INTERPRETATION: In this cohort of patients with intermediate-risk and high-risk localised prostate cancer, NHT plus WPRT improved progression-free survival compared with NHT plus PORT and WPRT plus AHT at long-term follow-up albeit increased risk of grade 3 or worse intestinal toxicity. Interactions between radiotherapy and hormonal therapy suggests that WPRT should be avoided without NHT. FUNDING: National Cancer Institute.

Prostate-specific antigen response after short-term hormone therapy plus external-beam radiotherapy and outcome in patients treated on Radiation Therapy Oncology Group study 9413.

BACKGROUND: The objective of this study was to assess the impact of a prostate-specific antigen (PSA) complete response (PSA-CR), measured at the end of external-beam radiotherapy and short-term hormone therapy, on treatment outcomes. METHODS: The phase 3 Radiation Therapy Oncology Group 9413 trial, as part of its original protocol, used the assessment of PSA-CR (ie, PSA ≤0.3 ng/mL) at the end of short-term HT as a secondary endpoint. Short-term HT consisted of futamide plus a lutenizing hormone-releasing hormone agonist for 4 months. The Kaplan-Meier method was used to estimate overall survival (OS) and disease-free survival. Cumulative incidence was used to estimate biochemical failure, distant metastasis, and disease-specific survival. Univariate and multivariate analyses were performed to correlate PSA-CR after short-term hormone therapy with all endpoints, and the following variables were considered for analysis: PSA at baseline, Gleason score, treatment arm, age, and baseline testosterone status. Phoenix consensus definition was used to define PSA failure. RESULTS: For 1070 evaluable patients, the median PSA at the end of short-term hormone therapy was 0.2 ng/mL. In total, 744 patients (70%) had a PSA-CR. At a median follow-up of 7.2 years, failure to obtain a PSA-CR was associated significantly with worse disease-specific survival (P = .0003; hazard ratio [HR], 2.03; 95% confidence interval [CI], 1.38-2.97), with worse disease-free survival (P = .003; HR, 1.28; 95% CI, 1.09-1.50), and with a higher incidence of distant metastasis (P = .0002; HR, 1.92; 95% CI, 1.37-2.69) and biochemical failure (P < .0001; HR, 1.57; 95% CI, 1.29-1.91). Other factors that were associated with worse disease-specific survival were Gleason scores from 8 to 10 (P = .0002; HR, 3.06; 95% CI, 1.71-5.47) and PSA levels >20 ng/mL (P = .04; HR, 1.55; 95% CI, 1.02-2.30). CONCLUSIONS: The current results indicated that failure to obtain a PSA-CR (PSA ≤0.3 ng/mL) after short-term hormone therapy and external-beam radiotherapy appears to be an independent predictor of unfavorable outcomes and could help identify patients who may benefit from the addition of long-term androgen ablation.

Quality of Life Implications of Dose-Escalated External Beam Radiation for Localized Prostate Cancer: Results of a Prospective Randomized Phase 3 Clinical Trial, NRG/RTOG 0126.

PURPOSE: External beam radiation therapy (EBRT) dose escalation has been tested in multiple prospective trials. However, the impact on patient reported outcomes (PROs) associated with higher doses of EBRT remain poorly understood. We sought to assess the differences in PROs between men treated with a dose of 70.2 Gy versus 79.2 Gy of EBRT for prostate cancer. METHODS AND MATERIALS: The phase 3 clinical trial RTOG 0126 randomized 1532 patients with prostate cancer between March 2002 and August 2008 to 79.2 Gy over 44 fractions versus 70.2 Gy over 39 fractions. Eligible patients participated in the PRO data collection. PROs completed included the International Index of Erectile Function Questionnaire (IIEF), Functional Alterations due to Changes in Elimination (FACE), and the Spitzer Quality of Life Index (SQLI). The timepoints for the IIEF were collected pre-entry and at 6, 12, and 24 months. The FACE and SQLI were collected pre-entry and at 3, 6, 12, 18, and 24 months. The impact of EBRT dose to normal structures (penile bulb, rectum, and bladder) on PROs was also examined. Mixed effects models were used to analyze trends across time. RESULTS: In total, 1144 patients completed baseline IIEF forms and of these, 56%, 64%, and 61% completed the IIEF at 6, 12, and 24 months, respectively; 1123 patients completed the FACE score at baseline and 50%, 61%, 73%, 61%, and 65% completed all 15 items for the FACE metric at timepoints of 3, 6, 12, 18, and 24 months, respectively. Erectile dysfunction at 12 months based on the single question was not significantly different between arms (38.1% for the standard dose radiation therapy arm vs 49.7% for the dose escalated radiation therapy arm; P = .051). Treatment arm (70.2 vs 79.2) had no significant impact on any PRO metrics measured across all collected domains. Comprehensive dosimetric analyses are presented and reveal multiple significant differences to regional organs at risk. CONCLUSIONS: Compliance with PRO data collection was lower than anticipated in this phase 3 trial. Examining the available data, dose escalated EBRT did not appear to be associated with any detriment to PROs across numerous prospectively collected domains. These data, notwithstanding limitations, add to our understanding of the implications of EBRT dose escalation in prostate cancer. Furthermore, these results illustrate challenges associated with PRO data collection.

Randomized phase III trial to evaluate radiopharmaceuticals and zoledronic acid in the palliation of osteoblastic metastases from lung, breast, and prostate cancer: report of the NRG Oncology RTOG 0517 trial.

BACKGROUND: Skeletal-related events (SREs), common sequelae of metastatic cancer, are reduced by bisphosphonates. In this study, it was postulated that radiopharmaceuticals, added to bisphosphonates, could further decrease the incidence of SREs. METHODS: NRG Oncology RTOG 0517 randomized patients with breast, lung, and prostate cancer and blastic bone metastases to either zoledronic acid (ZA) alone or ZA plus radiopharmaceuticals (Sr-89 or Sm-153). The primary endpoint was time to development of SREs. Secondary objectives included quality of life (QOL), pain control, overall survival (OS), and toxicity. RESULTS: 261 patients (median age 68; 62% male; 55% prostate, 35% breast, 10% lung) were accrued between July 2006 and February 2011. The study closed early due to a lower than expected rate of SREs. 52 (42%) patients in the ZA arm and 49 (40%) in the radiopharmaceutical arm experienced an SRE. Median time free of SREs was 29.9 and 27.4 months, respectively (p = 0.84). Median OS in the ZA arm and radiopharmaceutical arms was 32.1 and 26.9 months, respectively (p = 0.37). Cox proportional hazards regression model showed that primary disease site (lung) and number of bone metastases (> 2) had a negative impact on OS (p < 0.0001, p = 0.01, respectively). The addition of radiopharmaceuticals to ZA led to a significant reduction in pain at 1 month based on BPI worst score (p = 0.02). No other group differences were noted for QOL or toxicity. CONCLUSION: The addition of radiopharmaceuticals to bisphosphonates did not alter time to SREs or OS for patients with breast, lung, prostate cancers and blastic bone metastases, although it was associated with significant pain reduction at 1 month. CLINICAL TRIAL REGISTRY: This protocol (RTOG 0517) is registered with ClinicalTrials.gov (NCT00365105), and may be viewed online at http://www.clinicaltrials.gov/ct2/show/NCT00365105?term=RTOG+0517&rank=1 .

Quantifying Unnecessary Normal Tissue Complication Risks due to Suboptimal Planning: A Secondary Study of RTOG 0126.

PURPOSE: The purpose of this study was to quantify the frequency and clinical severity of quality deficiencies in intensity modulated radiation therapy (IMRT) planning in the Radiation Therapy Oncology Group 0126 protocol. METHODS AND MATERIALS: A total of 219 IMRT patients from the high-dose arm (79.2 Gy) of RTOG 0126 were analyzed. To quantify plan quality, we used established knowledge-based methods for patient-specific dose-volume histogram (DVH) prediction of organs at risk and a Lyman-Kutcher-Burman (LKB) model for grade ≥2 rectal complications to convert DVHs into normal tissue complication probabilities (NTCPs). The LKB model was validated by fitting dose-response parameters relative to observed toxicities. The 90th percentile (22 of 219) of plans with the lowest excess risk (difference between clinical and model-predicted NTCP) were used to create a model for the presumed best practices in the protocol (pDVH0126,top10%). Applying the resultant model to the entire sample enabled comparisons between DVHs that patients could have received to DVHs they actually received. Excess risk quantified the clinical impact of suboptimal planning. Accuracy of pDVH predictions was validated by replanning 30 of 219 patients (13.7%), including equal numbers of presumed "high-quality," "low-quality," and randomly sampled plans. NTCP-predicted toxicities were compared to adverse events on protocol. RESULTS: Existing models showed that bladder-sparing variations were less prevalent than rectum quality variations and that increased rectal sparing was not correlated with target metrics (dose received by 98% and 2% of the PTV, respectively). Observed toxicities were consistent with current LKB parameters. Converting DVH and pDVH0126,top10% to rectal NTCPs, we observed 94 of 219 patients (42.9%) with ≥5% excess risk, 20 of 219 patients (9.1%) with ≥10% excess risk, and 2 of 219 patients (0.9%) with ≥15% excess risk. Replanning demonstrated the predicted NTCP reductions while maintaining the volume of the PTV receiving prescription dose. An equivalent sample of high-quality plans showed fewer toxicities than low-quality plans, 6 of 73 versus 10 of 73 respectively, although these differences were not significant (P=.21) due to insufficient statistical power in this retrospective study. CONCLUSIONS: Plan quality deficiencies in RTOG 0126 exposed patients to substantial excess risk for rectal complications.

Duration of androgen suppression before radiotherapy for localized prostate cancer: radiation therapy oncology group randomized clinical trial 9910.

PURPOSE: To determine whether prolonged androgen suppression (AS) duration before radiotherapy improves survival and disease control in prostate cancer. PATIENTS AND METHODS: One thousand five hundred seventy-nine men with intermediate-risk prostate cancer were randomly assigned to 8 weeks of AS followed by radiotherapy with an additional 8 weeks of concurrent AS (16 weeks total) or to 28 weeks of AS followed by radiotherapy with an additional 8 weeks of AS (36 weeks total). The trial sought primarily to detect a 33% reduction in the hazard of prostate cancer death in the 28-week assignment. Time-to-event end points are reported for up to 10 years of follow-up. RESULTS: There were no between-group differences in baseline characteristics of 1,489 eligible patients with follow-up. For the 8- and 28-week assignments, 10-year disease-specific survival rates were 95% (95% CI, 93.3% to 97.0%) and 96% (95% CI, 94.6% to 98.0%; hazard ratio [HR], 0.81; P = .45), respectively, and 10-year overall survival rates were 66% (95% CI, 62.0% to 69.9%) and 67% (95% CI, 63.0% to 70.8%; HR, 0.95; P = .62), respectively. For the 8- and 28-week assignments, 10-year cumulative incidences of locoregional progression were 6% (95% CI, 4.3% to 8.0%) and 4% (95% CI, 2.5% to 5.7%; HR, 0.65; P = .07), respectively; 10-year distant metastasis cumulative incidences were 6% (95% CI, 4.0% to 7.7%) and 6% (95% CI, 4.0% to 7.6%; HR, 1.07; P = .80), respectively; and 10-year prostate-specific antigen-based recurrence cumulative incidences were 27% (95% CI, 23.1% to 29.8%) and 27% (95% CI, 23.4% to 30.3%; HR, 0.97; P = .77), respectively. CONCLUSION: Extending AS duration from 8 weeks to 28 weeks before radiotherapy did not improve outcomes. A lower than expected prostate cancer death rate reduced ability to detect a between-group difference in disease-specific survival. The schedule of 8 weeks of AS before radiotherapy plus 8 weeks of AS during radiotherapy remains a standard of care in intermediate-risk prostate cancer.

Development of RTOG consensus guidelines for the definition of the clinical target volume for postoperative conformal radiation therapy for prostate cancer.

PURPOSE: To define a prostate fossa clinical target volume (PF-CTV) for Radiation Therapy Oncology Group (RTOG) trials using postoperative radiotherapy for prostate cancer. METHODS AND MATERIALS: An RTOG-sponsored meeting was held to define an appropriate PF-CTV after radical prostatectomy. Data were presented describing radiographic failure patterns after surgery. Target volumes used in previous trials were reviewed. Using contours independently submitted by 13 radiation oncologists, a statistical imputation method derived a preliminary "consensus" PF-CTV. RESULTS: Starting from the model-derived CTV, consensus was reached for a CT image-based PF-CTV. The PF-CTV should extend superiorly from the level of the caudal vas deferens remnant to >8-12 mm inferior to vesicourethral anastomosis (VUA). Below the superior border of the pubic symphysis, the anterior border extends to the posterior aspect of the pubis and posteriorly to the rectum, where it may be concave at the level of the VUA. At this level, the lateral border extends to the levator ani. Above the pubic symphysis, the anterior border should encompass the posterior 1-2 cm of the bladder wall; posteriorly, it is bounded by the mesorectal fascia. At this level, the lateral border is the sacrorectogenitopubic fascia. Seminal vesicle remnants, if present, should be included in the CTV if there is pathologic evidence of their involvement. CONCLUSIONS: Consensus on postoperative PF-CTV for RT after prostatectomy was reached and is available as a CT image atlas on the RTOG website. This will allow uniformity in defining PF-CTV for clinical trials that include postprostatectomy RT.