Whole-pelvis, “mini-pelvis,” or prostate-only external beam radiotherapy after neoadjuvant and concurrent hormonal therapy in patients treated in the Radiation Therapy Oncology Group 9413 trial

Six-degrees-of-freedom pelvic bone monitoring on 2D kV intrafraction images to enable multi-target tracking for locally advanced prostate cancer

BACKGROUND

Patients with locally advanced prostate cancer require the prostate and pelvic lymph nodes to be irradiated simultaneously during radiation therapy treatment. However, relative motion between treatment targets decreases dosimetric conformity. Current treatment methods mitigate this error by having large treatment margins and often prioritize the prostate at patient setup at the cost of lymph node coverage.

PURPOSE

Treatment accuracy can be improved through real-time multi-target adaptation which requires simultaneous motion monitoring of both the prostate and lymph node targets. This study developed and evaluated an intrafraction pelvic bone motion monitoring method as a surrogate for pelvic lymph node displacement to be combined with prostate motion monitoring to enable multi-target six-degrees-of-freedom (6DoF) tracking using 2D kV projections acquired during treatment.

MATERIAL AND METHODS

A method to monitor pelvic bone translation and rotation was developed and retrospectively applied to images from 20 patients treated in the TROG 15.01 Stereotactic Prostate Ablative Radiotherapy with Kilovoltage Intrafraction Monitoring (KIM) trial. The pelvic motion monitoring method performed template matching to calculate the 6DoF position of the pelvis from 2D kV images. The method first generated a library of digitally reconstructed radiographs (DRRs) for a range of imaging angles and pelvic rotations. The normalized 2D cross-correlations were then calculated for each incoming kV image and a subset of DRRs and the DRR with the maximum correlation coefficient was used to estimate the pelvis translation and rotation. Translation of the pelvis in the unresolved direction was calculated using a 3D Gaussian probability estimation method. Prostate motion was measured using the KIM marker tracking method. The pelvic motion monitoring method was compared to the ground truth obtained from a 6DoF rigid registration of the CBCT and CT.

RESULTS

The geometric errors of the pelvic motion monitoring method demonstrated sub-mm and sub-degree accuracy and precision in the translational directions (T LR ${{T}_{{\mathrm{LR}}}}$ ,T SI ${{T}_{{\mathrm{SI}}}}$ ,T AP ${{T}_{{\mathrm{AP}}}}$ ) and rotational directions (R LR ${{R}_{{\mathrm{LR}}}}$ ,R SI ${{R}_{{\mathrm{SI}}}}$ ,R AP ${{R}_{{\mathrm{AP}}}}$ ). The 3D relative displacement between the prostate and pelvic bones exceeded 2, 3, 5, and 7 mm for approximately 66%, 44%, 12%, and 7% of the images.

CONCLUSIONS

Accurate intrafraction pelvic bone motion monitoring in 6DoF was demonstrated on 2D kV images, providing a necessary tool for real-time multi-target motion-adapted treatment.

Assessing the toxicity after moderately hypofractionated prostate and whole pelvis radiotherapy compared to conventional fractionation

OBJECTIVE

To evaluate acute and late gastrointestinal (GI) and genitourinary (GU) toxicities after moderately hypofractionated (HF) or conventionally fractionated (CF) primary whole-pelvis radiotherapy (WPRT).

METHODS

Primary prostate-cancer patients treated between 2009 and 2021 with either 60 Gy at 3 Gy/fraction to the prostate and 46 Gy at 2.3 Gy/fraction to the whole pelvis (HF), or 78 Gy at 2 Gy/fraction to the prostate and 50/50.4 Gy at 1.8-2 Gy/fraction to the whole pelvis (CF). Acute and late GI and GU toxicities were retrospectively assessed.

RESULTS

106 patients received HF and 157 received CF, with a median follow-up of 12 and 57 months. Acute GI toxicity rates in the HF and CF groups were, respectively, grade 2: 46.7% vs. 37.6%, and grade 3: 0% vs. 1.3%, with no significant difference (p = 0.71). Acute GU toxicity rates were, respectively, grade 2: 20.0% vs. 31.8%, and grade 3: 2.9% vs. 0%, (p = 0.04). We compared prevalence of late GI and GU toxicities between groups after 3, 12, and 24 months and did not find any significant differences (respectively, p = 0.59, 0.22, and 0.71 for GI toxicity; p = 0.39, 0.58, and 0.90 for GU toxicity).

CONCLUSION

Moderate HF WPRT was well tolerated during the first 2 years. Randomized trials are needed to confirm these findings.

Radiotherapy after radical prostatectomy for prostate cancer: clinical outcomes and factors influencing biochemical recurrence

BACKGROUND

Radiotherapy (RT) after radical prostatectomy (RP) includes adjuvant radiotherapy (ART) and salvage radiotherapy (SRT), which can prevent or cure biochemical recurrence.

AIMS

To evaluate long-term outcomes of RT after RP and to examine factors affecting biochemical recurrence-free survival (bRFS).

METHODS

Sixty-six received ART and 73 received SRT between 2005 and 2012 were included. The clinical outcomes and late toxicities were evaluated. Univariate and multivariate analyses were performed to examine factors affecting bRFS.

RESULTS

Median follow-up from RP was 111 months. Five-year bRFS and 10-year distant metastasis-free survival from RP were 82.8% and 84.5% in ART, and 74.6% and 92.4% in SRT, respectively. The most frequent late toxicity was hematuria, which was higher in ART (p = .01). No recurrence within RT field was occurred. On univariate analysis, pelvic RT was associated with favorable bRFS in ART (p = .048). In SRT, post-RP prostate-specific antigen (PSA) level (< 0.05 ng/mL), PSA nadir after RT (≤ 0.01 ng/mL), and time to PSA nadir (≥ 10 months) were associated with favorable bRFS (p = .03, p < .001, and p = .002, respectively). On multivariate analysis, post-RP PSA level and time to PSA nadir were independent predictive factors for bRFS in SRT (p = .04 and p = .005).

CONCLUSIONS

ART and SRT had favorable outcomes with no recurrence within RT field. In SRT, the time to PSA nadir after RT (≥ 10 months) was found to be a new predictor for favorable bRFS and useful in assessing treatment efficacy.

A Randomized Feasibility Trial of Stereotactic Prostate Radiation Therapy With or Without Elective Nodal Irradiation in High-Risk Localized Prostate Cancer (SPORT Trial)

PURPOSE

The aim of this study was to establish the feasibility of a randomized clinical trial comparing SABR with prostate-only (P-SABR) or with prostate plus pelvic lymph nodes (PPN-SABR) in patients with unfavorable intermediate- or high-risk localized prostate cancer and to explore potential toxicity biomarkers.

METHODS AND MATERIALS

Thirty adult men with at least 1 of the following features were randomized 1:1 to P-SABR or PPN-SABR: clinical magnetic resonance imaging stage T3a N0 M0, Gleason score ≥7 (4+3), and prostate-specific antigen >20 ng/mL. P-SABR patients received 36.25 Gy/5 fractions/29 days, and PPN-SABR patients received 25 Gy/5 fractions to pelvic nodes, with the final cohort receiving a boost to the dominant intraprostatic lesion of 45 to 50 Gy. Phosphorylated gamma-H2AX (γH2AX) foci numbers, citrulline levels, and circulating lymphocyte counts were quantified. Acute toxicity information (Common Terminology Criteria for Adverse Events, version 4.03) was collected weekly at each treatment and at 6 weeks and 3 months. Physician-reported late Radiation Therapy Oncology Group (RTOG) toxicity was recorded from 90 days to 36 months postcompletion of SABR. Patient-reported quality of life (Expanded Prostate Cancer Index Composite and International Prostate Symptom Score) scores were recorded with each toxicity time point.

RESULTS

The target recruitment was achieved, and treatment was successfully delivered in all patients. A total of 0% and 6.7% (P-SABR) and 6.7% and 20.0% (PPN-SABR) experienced acute grade ≥2 gastrointestinal (GI) and genitourinary (GU) toxicity, respectively. At 3 years, 6.7% and 6.7% (P-SABR) and 13.3% and 33.3% (PPN-SABR) had experienced late grade ≥2 GI and GU toxicity, respectively. One patient (PPN-SABR) had late grade 3 GU toxicity (cystitis and hematuria). No other grade ≥3 toxicity was observed. In addition, 33.3% and 60% (P-SABR) and 64.3% and 92.9% (PPN-SABR) experienced a minimally clinically important change in late Expanded Prostate Cancer Index Composite bowel and urinary summary scores, respectively. γH2AX foci numbers at 1 hour after the first fraction were significantly higher in the PPN-SABR arm compared with the P-SABR arm (P = .04). Patients with late grade ≥1 GI toxicity had significantly greater falls in circulating lymphocytes (12 weeks post-radiation therapy, P = .01) and a trend toward higher γH2AX foci numbers (P = .09) than patients with no late toxicity. Patients with late grade ≥1 bowel toxicity and late diarrhea experienced greater falls in citrulline levels (P = .05).

CONCLUSIONS

A randomized trial comparing P-SABR with PPN-SABR is feasible with acceptable toxicity. Correlations of γH2AX foci, lymphocyte counts, and citrulline levels with irradiated volume and toxicity suggest potential as predictive biomarkers. This study has informed a multicenter, randomized, phase 3 clinical trial in the United Kingdom.

Effect of Brachytherapy With External Beam Radiation Therapy Versus Brachytherapy Alone for Intermediate-Risk Prostate Cancer: NRG Oncology RTOG 0232 Randomized Clinical Trial

PURPOSE

To determine whether addition of external beam radiation therapy (EBRT) to brachytherapy (BT) (COMBO) compared with BT alone would improve 5-year freedom from progression (FFP) in intermediate-risk prostate cancer.

METHODS

Men with prostate cancer stage cT1c-T2bN0M0, Gleason Score (GS) 2-6 and prostate-specific antigen (PSA) 10-20 or GS 7, and PSA < 10 were eligible. The COMBO arm was EBRT (45 Gy in 25 fractions) to prostate and seminal vesicles followed by BT prostate boost (110 Gy if 125-Iodine, 100 Gy if 103-Pd). BT arm was delivered to prostate only (145 Gy if 125-Iodine, 125 Gy if 103-Pd). The primary end point was FFP: PSA failure (American Society for Therapeutic Radiology and Oncology [ASTRO] or Phoenix definitions), local failure, distant failure, or death.

RESULTS

Five hundred eighty-eight men were randomly assigned; 579 were eligible: 287 and 292 in COMBO and BT arms, respectively. The median age was 67 years; 89.1% had PSA < 10 ng/mL, 89.1% had GS 7, and 66.7% had T1 disease. There were no differences in FFP. The 5-year FFP-ASTRO was 85.6% (95% CI, 81.4 to 89.7) with COMBO compared with 82.7% (95% CI, 78.3 to 87.1) with BT (odds ratio [OR], 0.80; 95% CI, 0.51 to 1.26; Greenwood T P = .18). The 5-year FFP-Phoenix was 88.0% (95% CI, 84.2 to 91.9) with COMBO compared with 85.5% (95% CI, 81.3 to 89.6) with BT (OR, 0.80; 95% CI, 0.49 to 1.30; Greenwood T P = .19). There were no differences in the rates of genitourinary (GU) or GI acute toxicities. The 5-year cumulative incidence for late GU/GI grade 2+ toxicity is 42.8% (95% CI, 37.0 to 48.6) for COMBO compared with 25.8% (95% CI, 20.9 to 31.0) for BT (P < .0001). The 5-year cumulative incidence for late GU/GI grade 3+ toxicity is 8.2% (95% CI, 5.4 to 11.8) compared with 3.8% (95% CI, 2.0 to 6.5; P = .006).

CONCLUSION

Compared with BT, COMBO did not improve FFP for prostate cancer but caused greater toxicity. BT alone can be considered as a standard treatment for men with intermediate-risk prostate cancer.

Management of Patients with Advanced Prostate Cancer. Part I: Intermediate-/High-risk and Locally Advanced Disease, Biochemical Relapse, and Side Effects of Hormonal Treatment: Report of the Advanced Prostate Cancer Consensus Conference 2022

BACKGROUND

Innovations in imaging and molecular characterisation and the evolution of new therapies have improved outcomes in advanced prostate cancer. Nonetheless, we continue to lack high-level evidence on a variety of clinical topics that greatly impact daily practice. To supplement evidence-based guidelines, the 2022 Advanced Prostate Cancer Consensus Conference (APCCC 2022) surveyed experts about key dilemmas in clinical management.

OBJECTIVE

To present consensus voting results for select questions from APCCC 2022.

DESIGN, SETTING, AND PARTICIPANTS

Before the conference, a panel of 117 international prostate cancer experts used a modified Delphi process to develop 198 multiple-choice consensus questions on (1) intermediate- and high-risk and locally advanced prostate cancer, (2) biochemical recurrence after local treatment, (3) side effects from hormonal therapies, (4) metastatic hormone-sensitive prostate cancer, (5) nonmetastatic castration-resistant prostate cancer, (6) metastatic castration-resistant prostate cancer, and (7) oligometastatic and oligoprogressive prostate cancer. Before the conference, these questions were administered via a web-based survey to the 105 physician panel members ("panellists") who directly engage in prostate cancer treatment decision-making. Herein, we present results for the 82 questions on topics 1-3.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Consensus was defined as ≥75% agreement, with strong consensus defined as ≥90% agreement.

RESULTS AND LIMITATIONS

The voting results reveal varying degrees of consensus, as is discussed in this article and shown in the detailed results in the Supplementary material. The findings reflect the opinions of an international panel of experts and did not incorporate a formal literature review and meta-analysis.

CONCLUSIONS

These voting results by a panel of international experts in advanced prostate cancer can help physicians and patients navigate controversial areas of clinical management for which high-level evidence is scant or conflicting. The findings can also help funders and policymakers prioritise areas for future research. Diagnostic and treatment decisions should always be individualised based on patient and cancer characteristics (disease extent and location, treatment history, comorbidities, and patient preferences) and should incorporate current and emerging clinical evidence, therapeutic guidelines, and logistic and economic factors. Enrolment in clinical trials is always strongly encouraged. Importantly, APCCC 2022 once again identified important gaps (areas of nonconsensus) that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference (APCCC) provides a forum to discuss and debate current diagnostic and treatment options for patients with advanced prostate cancer. The conference aims to share the knowledge of international experts in prostate cancer with health care providers and patients worldwide. At each APCCC, a panel of physician experts vote in response to multiple-choice questions about their clinical opinions and approaches to managing advanced prostate cancer. This report presents voting results for the subset of questions pertaining to intermediate- and high-risk and locally advanced prostate cancer, biochemical relapse after definitive treatment, advanced (next-generation) imaging, and management of side effects caused by hormonal therapies. The results provide a practical guide to help clinicians and patients discuss treatment options as part of shared multidisciplinary decision-making. The findings may be especially useful when there is little or no high-level evidence to guide treatment decisions.

Effects of gold fiducial marker implantation on tumor control and toxicity in external beam radiotherapy of prostate cancer

BACKGROUND

Evidence regarding the effects of fiducials in image-guided radiotherapy (IGRT) for tumor control and acute and late toxicity is sparse.

PATIENTS AND METHODS

Patients with primary low- and intermediate-risk prostate cancer, 40 with and 21 without gold fiducial markers (GFM), and treated between 2010 and 2015 were retrospectively included. The decision for or against GFM implantation took anaesthetic evaluation and patient choice into account. IGRT was performed using electronic portal imaging devices. The prescribed dose was 78 Gy, with 2 Gy per fraction. Biochemical no evidence of disease (bNED) failure was defined using the Phoenix criteria. Acute and late gastrointestinal (GI) and genitourinary toxicity (GU) were assessed using the Radiation Therapy Oncology Group criteria.

RESULTS

Most patients did not receive GFM due to contraindications for anaesthesia or personal choice (60% and 25%). Regarding tumor control, no significant differences were found regarding bNED and overall and disease-specific survival (p = 0.61, p = 0.56, and p > 0.9999, respectively). No significant differences in acute and late GI (p = 0.16 and 0.64) and GU toxicity (p = 0.58 and 0.80) were observed.

CONCLUSIONS

We were unable to detect significant benefits in bNED or in early or late GI and GU side effects after GFM implantation.

DNA-methylation and genomic copy number in primary tumors and corresponding lymph node metastases in prostate cancer from patients with low and high Gleason score

Purpose

In prostate cancer, the indication to irradiate the pelvic lymphatic pathways in clinical node-negative patients is solely based on clinical nomograms. To define biological risk patterns of lymphatic spread, we studied DNA-methylation and genomic copy number in primary tumors and corresponding lymph nodes metastases.

Methods/Patients

DNA-methylation and genomic copy number profiles of primary tumors (PT) and paired synchronous lymph node metastases (LN) from Gleason Score (GS)-6/7a (n = 20 LN-positive, n = 20 LN-negative) and GS-9/10 patients (LN-positive n = 20) after prostatectomy and lymphonodectomy were analyzed.

Results

GS-6/7a pN0 PTs and GS-6/7a pN1 PTs differed in histone H3K27me3/H3K9me3 mediated methylation. PTs compared to LNs, in both, GS-6/7a pN1 and GS-9/10 pN1 patients showed large differences in DNA-methylation mediated by histones H3K4me1/2, in addition to copy number changes of chromosomal regions 11q13.1, 14q11.2 and 15q26.1. Between GS-6/7a pN1 and GS-9/10 pN1 patients, methylation levels differed more when comparing LNs than PTs. 16q21-22.1 was specifically lost in GS-9/10 pN0 PTs. Immune system-related pathways characterized the differences between PTs and LNs in both GS-6/7a pN1 and GS-9/10 pN1 patients. Comparing PTs and LKs between GS-6/7a pN1 and GS-9/10 pN1 patients revealed altered transmembrane and G-protein-coupled receptor signaling.

Conclusions

Our data suggest that progression of prostate cancer, including lymphatic spread, is associated with histone-mediated DNA-methylation and we hypothesize a methylation signature predicting lymphatic spread in GS-6/7a patients from primary tumors. Lymphatic spread in GS-6/7a patients, flanked by DNA-methylation and CNA alterations, appears to be more complex than in GS-9/10 patients, in whom the primary tumors already appear to bear lymph node metastasis-enabling alterations.

Adjuvant Radiotherapy in Stage II Endometrial Cancer: Selective De-intensification of Adjuvant Treatment

AIMS

Risk stratification, including nodal assessment, allows for selective de-intensification of adjuvant radiotherapy in stage II endometrial cancer. Patterns of treatment and clinical outcomes, including the use of reduced volume 'mini-pelvis' radiotherapy fields, were evaluated in a population-based study.

MATERIALS AND METHODS

All patients diagnosed with pathological stage II endometrial cancer between 2000 and 2014, and received adjuvant radiotherapy in a regional healthcare jurisdiction were reviewed. Registry data were supplemented by a comprehensive review of patient demographics, disease characteristics and treatment details. The Charlson Comorbidity Score was calculated. Survival and recurrence data were analysed.

RESULTS

In total, 264 patients met the inclusion criteria. Most patients had endometrioid histology (83%); 41% of patients had International Federation of Gynecologists and Obstetricians grade 1 disease. Half (49%) had surgical nodal evaluation; 11% received chemotherapy. Most patients (59%) were treated with full pelvic radiotherapy fields ± brachytherapy. Seventeen per cent of patients received mini-pelvis radiotherapy ± brachytherapy, whereas 24% received brachytherapy alone. Five-year recurrence-free survival was 87% for the entire cohort, with no significant difference by adjuvant radiotherapy approach. Only one patient receiving mini-pelvis radiotherapy ± brachytherapy recurred in the pelvis but outside of the mini-pelvis field. Recorded late toxicity rates were highest for full pelvis radiotherapy + brachytherapy.

CONCLUSION

Risk stratification in a real-world setting allowed for selective de-intensification of adjuvant radiation with equivalent outcomes for stage II endometrial cancer. Mini-pelvis radiotherapy combined with brachytherapy is effective in highly selected patients, with the potential to decrease toxicity without compromising local control. Brachytherapy should be considered in low-risk stage II patients.

Comparative effectiveness of moderate hypofractionation with volumetric modulated arc therapy versus conventional 3D-radiotherapy after radical prostatectomy

PURPOSE

Hypofractionated radiotherapy for prostate cancer is well established for definitive treatment, but not well defined in the postoperative setting. The purpose of this analysis was to assess oncologic outcomes and toxicity in a large cohort of patients treated with conventionally fractionated three-dimensional (3D) conformal radiotherapy (CF) and hypofractionated volumetric modulated arc therapy (HF) after radical prostatectomy.

METHODS

Between 1994 and 2019, a total of 855 patients with prostate carcinoma were treated by postoperative radiotherapy using CF (total dose 65-72 Gy, single fraction 1.8-2 Gy) in 572 patients and HF (total dose 62.5-63.75 Gy, single fraction 2.5-2.55 Gy) in 283 patients. The association of treatment modality with biochemical control, overall survival (OS), and gastrointestinal (GI) and genitourinary (GU) toxicity was assessed using logistic and Cox regression analysis.

RESULTS

There was no difference between the two modalities regarding biochemical control rates (77% versus 81%, respectively, for HF and CF at 24 months and 58% and 64% at 60 months; p = 0.20). OS estimates after 5 years: 95% versus 93% (p = 0.72). Patients undergoing HF had less frequent grade 2 or higher acute GI or GU side effects (p = 0.03 and p = 0.005, respectively). There were no differences in late GI side effects between modalities (hazard ratio 0.99). Median follow-up was 23 months for HF and 72 months for CF (p < 0.001).

CONCLUSION

For radiation therapy of resected prostate cancer, our analysis of this largest single-centre cohort (n = 283) treated with hypofractionation with advanced treatment techniques compared with conventional fractionation did not yield different outcomes in terms of biochemical control and toxicities. Prospective investigating of HF is merited.

Common iliac node positive prostate cancer treated with curative radiotherapy: N1 or M1a?

PURPOSE

Common iliac (CI) nodes are staged as (oligo)metastatic M1a for prostate cancer. It is unclear if outcomes of pelvic node-positive (cN1) differ from CI node-positive (CI-M1a) prostate cancer after curative treatment. Present study compares outcomes in these patients treated with radical whole pelvic radiotherapy and long-term ADT.

MATERIALS AND METHODS

Patients with node positive adenocarcinoma prostate were identified, either CI-M1a or cN1, from a prospectively maintained database. Over 75% of these patients were staged with Ga68PSMA-PETCT at diagnosis. All patients received long-term ADT and moderately or extremely hypofractionated radiotherapy to the prostate and pelvis including the CI region. At biochemical failure (BCF), restaging was done with Ga68PSMA-PETCT to establish the patterns of failure. CI-M1a cohort was classified as proximal or distal CI nodal location and studied for outcomes.

RESULTS

Of the 130 patients analyzed, 87 had cN1 and 43 had CI-M1a stage. Median duration of ADT before RT was 7 months and total duration was atleast 24 months. Majority (65%) had Gleason grade group IV-V while 75% had ≥T3 disease. After a median FU of 61 months, BCF in the 2 groups were similar, cN1, 21/87 (24.1%); CI-M1a, 11/43 (25.6%), p=0.86. At BCF, restaging Ga68-PSMA-PET-CT located distant metastases in 20 (63%) of the 32 patients (57% in cN1, and 73% in CI-M1a, p=0.47). Five-year biochemical failure-free survival (cN1; 77.4% and CI-M1a; 70.4%, p=0.43), distant metastasis-free survival (cN1; 86.9% and CI-M1a; 79.4%, p=0.23) and overall survival (cN1 92.6% and CI-M1a 90.1%, p=0.80) were similar in the two groups. Outcomes within CI-M1a were similar for proximal versus distal CI nodal location, 5-year BFFS 73.6% vs 58.6% (p=0.81).

CONCLUSION

Oligometastatic CI-M1a and cN1 prostate cancer patients showed similar outcomes when treated with curative whole pelvic radiotherapy and long-term ADT. The treatment for these 'oligometastatic' patients should be prospectively evaluated and optimized accordingly.

Efficacy and Toxicity of Whole Pelvic Radiotherapy Versus Prostate-Only Radiotherapy in Localized Prostate Cancer: A Systematic Review and Meta-Analysis

Background

There is little level 1 evidence regarding the relative efficacy and toxicity of whole pelvic radiotherapy (WPRT) compared with prostate-only radiotherapy (PORT) for localized prostate cancer.

Methods

We used Cochrane, PubMed, Embase, Medline databases, and ClinicalTrials.gov to systematically search for all relevant clinical studies. The data on efficacy and toxicity were extracted for quality assessment and meta-analysis to quantify the effect of WPRT on biochemical failure-free survival (BFFS), progression-free survival (PFS), distant metastasis-free survival (DMFS), overall survival (OS), gastrointestinal (GI) toxicity, and genitourinary (GU) toxicity compared with PORT. The review is registered on PROSPERO, number: CRD42021254752.

Results

The results revealed that compared with PORT, WPRT significantly improved 5-year BFFS and PFS, and it was irrelevant to whether the patients had undergone radical prostatectomy (RP). In addition, for the patients who did not receive RP, the 5-year DMFS of WPRT was better than that of PORT. However, WPRT significantly increased not only the grade 2 or worse (G2+) acute GI toxicity of non-RP studies and RP studies, but also the G2+ late GI toxicity of non-RP studies. Subgroup analysis of non-RP studies found that, when the pelvic radiation dose was >49 Gy (equivalent-doses-in-2-Gy-fractions, EQD-2), WPRT was more beneficial to PFS than PORT, but significantly increased the risk of G2+ acute and late GU toxicity.

Conclusions

Meta-analysis demonstrates that WPRT can significantly improve BFFS and PFS for localized prostate cancer than PORT, but the increased risk of G2+ acute and late GI toxicity must be considered.

Systematic Review Registration

PROSPERO CRD42021254752.

Safety of accelerated hypofractionated whole pelvis radiation therapy prior to high dose rate brachytherapy or stereotactic body radiation therapy prostate boost

Background

To evaluate acute and late genitourinary and gastrointestinal toxicities and patient reported urinary and sexual function following accelerated, hypofractionated external beam radiotherapy to the prostate, seminal vesicles and pelvic lymph nodes and high dose rate (HDR) brachytherapy or stereotactic body radiation therapy (SBRT) prostate boost.

Methods

Patients at a single institution with NCCN intermediate- and high-risk localized prostate cancer with logistical barriers to completing five weeks of whole pelvic radiotherapy (WPRT) were retrospectively reviewed for toxicity following accelerated, hypofractionated WPRT (41.25 Gy in 15 fractions of 2.75 Gy). Patients also received prostate boost radiotherapy with either HDR brachytherapy (1 fraction of 15 Gy) or SBRT (19 Gy in 2 fractions of 9.5 Gy). The duration of androgen deprivation therapy was at the discretion of the treating radiation oncologist. Toxicity was evaluated by NCI CTCAE v 5.0.

Results

Between 2015 and 2017, 22 patients with a median age of 71 years completed accelerated, hypofractionated WPRT. Median follow-up from the end of radiotherapy was 32 months (range 2–57). 5%, 73%, and 23% of patients had clinical T1, T2, and T3 disease, respectively. 86% of tumors were Gleason grade 7 and 14% were Gleason grade 9. 68% and 32% of patients had NCCN intermediate- and high-risk disease, respectively. 91% and 9% of patients received HDR brachytherapy and SBRT prostate boost following WPRT, respectively. Crude rates of grade 2 or higher GI and GU toxicities were 23% and 23%, respectively. 3 patients (14%) had late or persistent grade 2 toxicities of urinary frequency and 1 patient (5%) had late or persistent GI toxicity of diarrhea. No patient experienced grade 3 or higher toxicity at any time. No difference in patient-reported urinary or sexual function was noted at 12 months.

Conclusions

Accelerated, hypofractionated whole pelvis radiotherapy was associated with acceptable GU and GI toxicities and should be further validated for those at risk for harboring occult nodal disease.

External radiotherapy for prostatic cancers

We present the update of the recommendations of the French society of oncological radiotherapy on external radiotherapy of prostate cancer. External radiotherapy is intended for all localized prostate cancers, and more recently for oligometastatic prostate cancers. The irradiation techniques are detailed. Intensity-modulated radiotherapy combined with prostate image-guided radiotherapy is the recommended technique. A total dose of 74 to 80Gy is recommended in case of standard fractionation (2Gy per fraction). Moderate hypofractionation (total dose of 60Gy at a rate of 3Gy per fraction over 4 weeks) in the prostate has become a standard of therapy. Simultaneous integrated boost techniques can be used to treat lymph node areas. Extreme hypofractionation (35 to 40Gy in five fractions) using stereotactic body radiotherapy can be considered a therapeutic option to treat exclusively the prostate. The postoperative irradiation technique, indicated mainly in case of biological recurrence and lymph node involvement, is detailed.

Ten Year Results of Extensive Nodal Radiotherapy and Moderately Hypofractionated Simultaneous Integrated Boost in Unfavorable Intermediate-, High-, and Very High-Risk Prostate Cancer

Simple Summary

Several phase III randomized trials of moderate hypofractionation, including a higher proportion of high-risk prostate cancer patients treated only to the prostate, failed to demonstrate the superiority of hypofractionated regimens. There is only one randomized phase III trial, of moderately hypofractionated high-dose radiotherapy to the prostate-only versus pelvic irradiation and prostate boost, with a sufficiently long follow-up. It demonstrated better biochemical and disease-free survival when lymph nodal radiotherapy was added. Here we present the 10-year results of our experience based on an Institutional protocol adopted after a phase I–II study, on patients with unfavorable intermediate- (UIR), high- (HR), and very high-risk (VHR) prostate cancer (PCa) treated with pelvic lymph nodal irradiation (WPRT) and moderately hypofractionated high-dose (HD) simultaneous integrated boost (SIB) to the prostate. Prognostic factors for relapse, as well as acute and late gastro-intestinal (GI) and genito-urinary (GU) toxicity were also analyzed.

Abstract

Aims: To report 10-year outcomes of WPRT and HD moderately hypofractionated SIB to the prostate in UIR, HR, and VHR PCa. Methods: From 11/2005 to 12/2015, 224 UIR, HR, and VHR PCa patients underwent WPRT at 51.8 Gy/28 fractions and SIB at 74.2 Gy (EQD2 88 Gy) to the prostate. Androgen deprivation therapy (ADT) was prescribed in up to 86.2% of patients. Results: Median follow-up was 96.3 months (IQR: 71–124.7). Median age was 75 years (IQR: 71.3–78.1). At last follow up, G3 GI–GU toxicity was 3.1% and 8%, respectively. Ten-year biochemical relapse-free survival (bRFS) was 79.8% (95% CI: 72.3–88.1%), disease-free survival (DFS) 87.8% (95% CI: 81.7–94.3%), overall survival (OS) 65.7% (95% CI: 58.2–74.1%), and prostate cancer-specific survival (PCSS) 94.9% (95% CI: 91.0–99.0%). Only two patients presented local relapse. At univariate analysis, VHR vs. UIR was found to be a significant risk factor for biochemical relapse (HR: 2.8, 95% CI: 1.17–6.67, p = 0.021). After model selection, only Gleason Score ≥ 8 emerged as a significant factor for biochemical relapse (HR = 2.3, 95% CI: 1.12–4.9, p = 0.023). Previous TURP (HR = 3.5, 95% CI: 1.62–7.54, p = 0.001) and acute toxicity ≥ G2 (HR = 3.1, 95% CI = 1.45–6.52, p = 0.003) were significant risk factors for GU toxicity ≥ G3. Hypertension was a significant factor for GI toxicity ≥ G3 (HR = 3.63, 95% CI: 1.06–12.46, p = 0.041). ADT (HR = 0.31, 95% CI: 0.12–0.8, p = 0.015) and iPsa (HR = 0.37, 95% CI: 0.16–0.83, p = 0.0164) played a protective role. Conclusions: WPRT and HD SIB to the prostate combined with long-term ADT, in HR PCa, determine good outcomes with acceptable toxicity.

A Critical Review of Radiation Therapy: From Particle Beam Therapy (Proton, Carbon, and BNCT) to Beyond

In this paper, we discuss the role of particle therapy—a novel radiation therapy (RT) that has shown rapid progress and widespread use in recent years—in multidisciplinary treatment. Three types of particle therapies are currently used for cancer treatment: proton beam therapy (PBT), carbon-ion beam therapy (CIBT), and boron neutron capture therapy (BNCT). PBT and CIBT have been reported to have excellent therapeutic results owing to the physical characteristics of their Bragg peaks. Variable drug therapies, such as chemotherapy, hormone therapy, and immunotherapy, are combined in various treatment strategies, and treatment effects have been improved. BNCT has a high dose concentration for cancer in terms of nuclear reactions with boron. BNCT is a next-generation RT that can achieve cancer cell-selective therapeutic effects, and its effectiveness strongly depends on the selective ¹⁰B accumulation in cancer cells by concomitant boron preparation. Therefore, drug delivery research, including nanoparticles, is highly desirable. In this review, we introduce both clinical and basic aspects of particle beam therapy from the perspective of multidisciplinary treatment, which is expected to expand further in the future.

Effective Organs-at-Risk Dose Sparing in Volumetric Modulated Arc Therapy Using a Half-Beam Technique in Whole Pelvic Irradiation

BACKGROUND

Although there are some controversies regarding whole pelvic radiation therapy (WPRT) due to its gastrointestinal and hematologic toxicities, it is considered for patients with gynecological, rectal, and prostate cancer. To effectively spare organs-at-risk (OAR) doses using multi-leaf collimator (MLC)'s optimal segments, potential dosimetric benefits in volumetric modulated arc therapy (VMAT) using a half-beam technique (HF) were investigated for WPRT.

METHODS

While the size of a fully opened field (FF) was decided to entirely include a planning target volume in all beam's eye view across arc angles, the HF was designed to use half the FF from the isocenter for dose optimization. The left or the right half of the FF was alternatively opened in VMAT-HF using a pair of arcs rotating clockwise and counterclockwise. Dosimetric benefits of VMAT-HF, presented with dose conformity, homogeneity, and dose-volume parameters in terms of modulation complex score, were compared to VMAT optimized using the FF (VMAT-FF). Consequent normal tissue complication probability (NTCP) by reducing the irradiated volumes was evaluated as well as dose-volume parameters with statistical analysis for OAR. Moreover, beam-on time and MLC position precision were analyzed with log files to assess plan deliverability and clinical applicability of VMAT-HF as compared to VMAT-FF.

RESULTS

While VMAT-HF used 60%-70% less intensity modulation complexity than VMAT-FF, it showed superior dose conformity. The small intestine and colon in VMAT-HF showed a noticeable reduction in the irradiated volumes of up to 35% and 15%, respectively, at an intermediate dose of 20-45 Gy. The small intestine showed statistically significant dose sparing at the volumes that received a dose from 15 to 45 Gy. Such a dose reduction for the small intestine and colon in VMAT-HF presented a significant NTCP reduction from that in VMAT-FF. Without sacrificing the beam delivery efficiency, VMAT-HF achieved effective OAR dose reduction in dose-volume histograms.

CONCLUSIONS

VMAT-HF led to deliver conformal doses with effective gastrointestinal-OAR dose sparing despite using less modulation complexity. The dose of VMAT-HF was delivered with the same beam-on time with VMAT-FF but precise MLC leaf motions. The VMAT-HF potentially can play a valuable role in reducing OAR toxicities associated with WPRT.

Intensity-Modulated Radiation Therapy with Simultaneous Integrated Boost for Clinically Node-Positive Prostate Cancer: A Single-Institutional Retrospective Study

Simple Summary

Recently, it has been shown that radiation therapy (RT) together with androgen-depletion therapy (ADT) might be more beneficial compared with ADT alone for clinically node-positive (cN1) prostate cancer. However, there are a limited number of studies that have addressed specific RT techniques and analyzed their clinical results. The present study was a retrospective analysis of cN1 prostate cancer patients treated with intensity-modulated radiation therapy with simultaneous integrated boost (SIB-IMRT), in addition to ADT, in our hospital. The present study suggests that ADT plus SIB-IMRT for cN1 prostate cancer treatment was safe and effective, was well tolerated, and had acceptable rates of late toxicity. Further prospective multicenter studies would be required to confirm the robustness of the present results.

Abstract

This study aimed to evaluate clinical outcomes and the toxicity of intensity-modulated radiation therapy with simultaneous integrated boost (SIB-IMRT) combined with androgen-deprivation therapy for clinically node-positive (cN1) prostate cancer. We retrospectively analyzed 97 patients with cN1 prostate cancer who received SIB-IMRT between June 2008 and October 2017 at our hospital. The prescribed dosages delivered to the prostate and seminal vesicle, elective node area, and residual lymph nodes were 69, 54, and 60 Gy in 30 fractions, respectively. Kaplan–Meier analysis was used to determine 5-year biochemical relapse-free survival (bRFS), relapse-free survival (RFS), overall survival (OS), and prostate cancer-specific survival (PCSS). Toxicity was evaluated using the Common Terminology Criteria for Adverse Events ver. 4.0. Over a median follow-up duration of 60 months, the 5-year bRFS, RFS, OS, and PCSS were 85.1%, 88.1%, 92.7% and 95.0%, respectively. Acute Grade 2 genito-urinary (GU) and gastro-intestinal (GI) toxicities were observed in 10.2% and 2.1%, respectively, with no grade ≥3 toxicities being detected. The cumulative incidence rates of 5-year Grade ≥2 late GU and GI toxicities were 4.7% and 7.4%, respectively, with no Grade 4 toxicities being detected. SIB-IMRT for cN1 prostate cancer demonstrated favorable 5-year outcomes with low incidences of toxicity.

Prostate-Only Versus Whole-Pelvic Radiation Therapy in High-Risk and Very High-Risk Prostate Cancer (POP-RT): Outcomes From Phase III Randomized Controlled Trial

PURPOSE

We report the clinical outcomes of a randomized trial comparing prophylactic whole-pelvic nodal radiotherapy to prostate-only radiotherapy (PORT) in high-risk prostate cancer.

METHODS

This phase III, single center, randomized controlled trial enrolled eligible patients undergoing radical radiotherapy for node-negative prostate adenocarcinoma, with estimated nodal risk ≥ 20%. Randomization was 1:1 to PORT (68 Gy/25# to prostate) or whole-pelvic radiotherapy (WPRT, 68 Gy/25# to prostate, 50 Gy/25# to pelvic nodes, including common iliac) using computerized stratified block randomization, stratified by Gleason score, type of androgen deprivation, prostate-specific antigen at diagnosis, and prior transurethral resection of the prostate. All patients received image-guided, intensity-modulated radiotherapy and minimum 2 years of androgen deprivation therapy. The primary end point was 5-year biochemical failure-free survival (BFFS), and secondary end points were disease-free survival (DFS) and overall survival (OS).

RESULTS

From November 2011 to August 2017, a total of 224 patients were randomly assigned (PORT = 114, WPRT = 110). At a median follow-up of 68 months, 36 biochemical failures (PORT = 25, WPRT = 7) and 24 deaths (PORT = 13, WPRT = 11) were recorded. Five-year BFFS was 95.0% (95% CI, 88.4 to 97.9) with WPRT versus 81.2% (95% CI, 71.6 to 87.8) with PORT, with an unadjusted hazard ratio (HR) of 0.23 (95% CI, 0.10 to 0.52; P < .0001). WPRT also showed higher 5-year DFS (89.5% v 77.2%; HR, 0.40; 95% CI, 0.22 to 0.73; P = .002), but 5-year OS did not appear to differ (92.5% v 90.8%; HR, 0.92; 95% CI, 0.41 to 2.05; P = .83). Distant metastasis-free survival was also higher with WPRT (95.9% v 89.2%; HR, 0.35; 95% CI, 0.15 to 0.82; P = .01). Benefit in BFFS and DFS was maintained across prognostic subgroups.

CONCLUSION

Prophylactic pelvic irradiation for high-risk, locally advanced prostate cancer improved BFFS and DFS as compared with PORT, but OS did not appear to differ.

NRG Oncology Updated International Consensus Atlas on Pelvic Lymph Node Volumes for Intact and Postoperative Prostate Cancer

PURPOSE

In 2009, the Radiation Therapy Oncology Group (RTOG) genitourinary members published a consensus atlas for contouring prostate pelvic nodal clinical target volumes (CTVs). Data have emerged further informing nodal recurrence patterns. The objective of this study is to provide an updated prostate pelvic nodal consensus atlas.

METHODS AND MATERIALS

A literature review was performed abstracting data on nodal recurrence patterns. Data were presented to a panel of international experts, including radiation oncologists, radiologists, and urologists. After data review, participants contoured nodal CTVs on 3 cases: postoperative, intact node positive, and intact node negative. Radiation oncologist contours were analyzed qualitatively using count maps, which provided a visual assessment of controversial regions, and quantitatively analyzed using Sorensen-Dice similarity coefficients and Hausdorff distances compared with the 2009 RTOG atlas. Diagnostic radiologists generated a reference table outlining considerations for determining clinical node positivity.

RESULTS

Eighteen radiation oncologists' contours (54 CTVs) were included. Two urologists' volumes were examined in a separate analysis. The mean CTV for the postoperative case was 302 cm3, intact node positive case was 409 cm3, and intact node negative case was 342 cm3. Compared with the original RTOG consensus, the mean Sorensen-Dice similarity coefficient for the postoperative case was 0.63 (standard deviation [SD] 0.13), the intact node positive case was 0.68 (SD 0.13), and the intact node negative case was 0.66 (SD 0.18). The mean Hausdorff distance (in cm) for the postoperative case was 0.24 (SD 0.13), the intact node positive case was 0.23 (SD 0.09), and intact node negative case was 0.33 (SD 0.24). Four regions of CTV controversy were identified, and consensus for each of these areas was reached.

CONCLUSIONS

Discordance with the 2009 RTOG consensus atlas was seen in a group of experienced NRG Oncology and international genitourinary radiation oncologists. To address areas of variability and account for new data, an updated NRG Oncology consensus contour atlas was developed.

Incidental testicular doses during volumetric-modulated arc radiotherapy in prostate cancer patients

PURPOSE

To compare the incidental testicular doses during volumetric-modulated arc therapy (VMAT) in patients receiving prostate-only and pelvic lymphatic irradiation.

MATERIALS AND METHODS

Testicular doses in 40 intermediate- and high-risk prostate cancer patients were determined on treatment planning system (TPS) using the VMAT technique at 6 MV. Scattered testicular doses were also measured by MOSFET detectors placed on testis surface. The testicular doses of patients treated with prostate-only and pelvic field irradiation were compared.

RESULTS

The median testicular doses measured per 200 cGy fraction by TPS and MOSFET detectors were 1.7 cGy (0.7-4.1 cGy) and 4.8 cGy (3.6-8.8 cGy), respectively. The TPS doses and MOSFET readings showed a significant strong correlation (Pearson r = 0.848, p < 0.001). The testicular doses measured by TPS (1.34 ± 0.36 cGy vs. 2.60 ± 0.95 cGy; p < 0.001) and MOSFET (4.52 ± 0.64 cGy vs. 6.56 ± 1.23 cGy; p < 0.001) were significantly lower in patients with prostate-only irradiation than in those with pelvic field irradiation. The mean cumulative scattered dose for prostate-only field delivering 78 Gy was 1.8 Gy and that for pelvic field irradiation was 2.6 Gy, consistent with the reported findings.

CONCLUSIONS

The patients with prostate-only irradiation received lower testicular doses than those with additional pelvic field irradiation possibly due to the increased scattered doses in large field irradiation using the VMAT technique. The clinical response to increased incidental testicular doses due to pelvic field irradiation remains unknown, and it warrants further investigation.

Prostate cancer with low burden skeletal disease at diagnosis: outcome of concomitant radiotherapy on primary tumor and metastases

OBJECTIVE

To evaluate toxicity and clinical outcome in synchronous bone only oligometastatic (≤2 lesions) prostate cancer patients, simultaneously irradiated to prostate/prostatic bed, lymph nodes and bone metastases.

METHODS

From 2/2009 to 6/2015, 39 bone only prostate cancer patients underwent radiotherapy (RT) at "radical" doses to bone metastases (median 2 Gy equivalent dose, EQD2>40Gy, α/β = 1,5), nodes, and prostate/prostatic bed, within the same RT course, in association with androgen deprivation therapy (ADT).Biochemical relapse-free survival, clinical relapse-free survival, freedom from distant metastases and overall survival were evaluated.

RESULTS

After a median follow-up of 46.5 (1.2-103.6) months, 5 patients died from disease progression, 10 experienced biochemical relapse, 19, still in ADT, presented undetectable prostate-specific antigen (PSA) at the last follow-up. Five patients who discontinued ADT after a median of 34 months (5.8-41) are free from biochemical relapse.The 4 year Kaplan-Meier estimates of biochemical relapse-free survival, clinical relapse-free survival, freedom from distant metastases and overall survival were 53.3%, 65.7%, 73.4% and 82.4% respectively.No Grade > 2 acute events and only two severe late urinary events were recorded, not due to the concomitant treatment of primary and metastatic disease.

CONCLUSION

Our results suggest that "radical" and synchronous irradiation of primitive tumor and metastatic disease may be a valid approach in synchronous bone only prostate cancer patients, showing mild toxicity profile and promising survival results.

ADVANCES IN KNOWLEDGE

To the best of our knowledge, this is the first analysis of clinical outcome in synchronous bone-only metastasis (neither nodal nor visceral) patients at diagnosis, treated with radical RT to all disease, associated to ADT.

[Prophylactic nodal radiotherapy in prostate cancer]

The risk of lymph node invasion, in case of prostate cancer, increases with the clinical stage of the disease, the Gleason score of prostate biopsies and the value of PSA at diagnosis. Historically, beyond 15% risk of lymph node involvement, irradiation of the pelvic areas was performed with prostate radiotherapy (RT) to take into account the risk of occult lymph node metastasis in patients at risk, but the benefit of this therapeutic approach remains to be demonstrated. The data from surgical lymph node dissection seem to question the risk levels, the escalation of the dose on the prostate increases the survival without relapse, the contribution of image-guided radiotherapy, (IGRT) and modulation of intensity (IMRT), decreases the toxicity of pelvic RT. This article reviews the principles of prophylactic ganglion irradiation for prostate cancer and discusses its relevance, current uncertainties, and prospective trials.

Treatment-Related Toxicity Using Prostate-Only Versus Prostate and Pelvic Lymph Node Intensity-Modulated Radiation Therapy: A National Population-Based Study

PURPOSE

There is a debate about the effectiveness and toxicity of pelvic lymph node (PLN) irradiation for the treatment of men with high-risk prostate cancer. This study compared the toxicity of intensity-modulated radiation therapy (IMRT) to the prostate and the pelvic lymph nodes (PPLN-IMRT) with prostate-only IMRT (PO-IMRT).

MATERIALS AND METHODS

Patients with high-risk localized or locally advanced prostate cancer treated with IMRT in the English National Health Service between 2010 and 2013 were identified by using data from the Cancer Registry, the National Radiotherapy Dataset, and Hospital Episode Statistics, an administrative database of all hospital admissions. Follow-up was available up to December 31, 2015. Validated indicators were used to identify patients with severe toxicity according to the presence of both a procedure code and diagnostic code in patient Hospital Episode Statistics records. A competing risks regression analysis, with adjustment for patient and tumor characteristics, estimated subdistribution hazard ratios (sHRs) by comparing GI and genitourinary (GU) complications for PPLN-IMRT versus PO-IMRT.

RESULTS

Three-year cumulative incidence in the PPLN-IMRT (n = 780) and PO-IMRT (n = 3,065) groups was 14% for both groups for GI toxicity, and 9% and 8% for GU toxicity, respectively. Patients receiving PPLN-IMRT and PO-IMRT had similar levels of severe GI (adjusted sHR, 1.00; 95% CI, 0.80 to 1.24; P = .97) and GU (adjusted sHR, 1.10; 95% CI, 0.83 to 1.46; P = .50) toxicity rates.

CONCLUSION

Including PLNs in radiation fields for high-risk or locally advanced prostate cancer is not associated with increased GI or GU toxicity at 3 years. Additional follow-up is required to answer questions about its impact on late GU toxicity. Results from ongoing trials will provide insight into the anticancer effectiveness of PLN irradiation.

Particle therapy for prostate cancer: The past, present and future

Although prostate cancer control using radiotherapy is dose‐dependent, dose–volume effects on late toxicities in organs at risk, such as the rectum and bladder, have been observed. Both protons and carbon ions offer advantageous physical properties for radiotherapy, and create favorable dose distributions using fewer portals compared with photon‐based radiotherapy. Thus, particle beam therapy using protons and carbon ions theoretically seems suitable for dose escalation and reduced risk of toxicity. However, it is difficult to evaluate the superiority of particle beam radiotherapy over photon beam radiotherapy for prostate cancer, as no clinical trials have directly compared the outcomes between the two types of therapy due to the limited number of facilities using particle beam therapy. The Japanese Society for Radiation Oncology organized a joint effort among research groups to establish standardized treatment policies and indications for particle beam therapy according to disease, and multicenter prospective studies have been planned for several common cancers. Clinical trials of proton beam therapy for intermediate‐risk prostate cancer and carbon‐ion therapy for high‐risk prostate cancer have already begun. As particle beam therapy for prostate cancer is covered by the Japanese national health insurance system as of April 2018, and the number of facilities practicing particle beam therapy has increased recently, the number of prostate cancer patients treated with particle beam therapy in Japan is expected to increase drastically. Here, we review the results from studies of particle beam therapy for prostate cancer and discuss future developments in this field.

Impact of daily soft-tissue image guidance to prostate on pelvic lymph node (PLN) irradiation for prostate patients receiving SBRT

PURPOSE

To determine the impact of using fiducial match for daily image-guidance on pelvic lymph node (PLN) coverage for prostate cancer patients receiving stereotactic body radiation therapy (SBRT).

METHODS

Thirty patients underwent SBRT treatment to the prostate and PLN from 2014 to 2016. Each patient received either 800cGy × 5 or 500cGy × 5 to the prostate and 500cGy × 5 to the PLN. A 5 mm clinical target volume (CTV)-to-planning target volume (PTV) margin around the PLN was used for planning. Two registrations with planning computed tomography (PCT) for each of the daily cone beam CTs (CBCTs) were performed: a rigid registration to fiducials and to the bony anatomy. The average translational difference between fiducial and bony match as well as percentage of fractions with differences > 5mm were calculated. Changes in bladder and rectal volume as well as center-of-mass (COM) position from simulation parameters, and their correlation with translational difference were also evaluated. The dosimetric impact of the translational differences was calculated by shifting the plan isocenter.

RESULTS

The average translational difference between fiducial and bony match was 0.06 ± 0.82, 2.1 ± 4.1, -2.8 ± 4.3, and 5.5 ± 4.2 mm for lateral, vertical, longitudinal, and vector directions. The average change in bladder and rectal volume from simulation was -67.2 ± 163.04 cc (-12 ± 52%) and -1.6 ± 18.75 (-2 ± 30%) cc. The average change in COM of bladder from the simulation position was 0.34 ± 2.49, 4.4 ± 8.1, and -3.9 ± 7.5 mm along the LR, AP, and SI directions. The corresponding COM change for the rectum was 0.17 ± 1.9, 1.34 ± 3.5, and -0.6 ± 5.2 mm.

CONCLUSIONS

The 5 mm margin covered ~75% of fractions receiving PLN irradiation with SBRT, daily CBCT and fiducial-guided setup. The dosimetric impact on PLN coverage was significant in 19% of fractions or 25% of patients. A larger translational shift was due to variation in rectal volume and changes in COM position of the bladder and rectum. A consistent bladder positioning and/or rectum filling compared with presimulation volume were essential for adequate coverage of PLN in a hypofractionated treatment regime.

Genomic Risk Predicts Molecular Imaging-detected Metastatic Nodal Disease in Prostate Cancer

BACKGROUND

The Decipher genomic classifier (GC) is increasingly being used to determine metastasis risk in men with localized prostate cancer (PCa). Whether GCs predict for the presence of occult metastatic disease at presentation or subsequent metastatic progression is unknown.

OBJECTIVE

To determine if GC scores predict extraprostatic ⁶⁸Ga prostate-specific membrane antigen (⁶⁸Ga-PSMA-11) positron emission tomography (PET) positivity at presentation.

DESIGN, SETTING, AND PARTICIPANTS

Between December 2015 and September 2018, 91 PCa patients with both GC scores and pretreatment ⁶⁸Ga-PSMA-11 PET scans were identified. Risk stratification was performed using the National Comprehensive Cancer Network (NCCN), Cancer of the Prostate Risk Assessment (CAPRA), and GC scores.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Logistic regression was used to identify factors correlated with PSMA-positive disease.

RESULTS AND LIMITATIONS

The NCCN criteria identified 23 (25.3%) and 68 patients (74.7%) as intermediate and high risk, while CAPRA scores revealed 28 (30.8%) and 63 (69.2%) as low/intermediate and high risk, respectively. By contrast, only 45 patients (49.4%) had high-risk GC scores. PSMA-avid pelvic nodal involvement was identified in 27 patients (29.7%). Higher GC score was significantly associated with pelvic nodal involvement (odds ratio [OR] 1.38 per 0.1 units; p=0.009) and any PSMA-avid nodal involvement (pelvic or distant; OR 1.40 per 0.1 units; p=0.007). However, higher GC score was not significantly associated with PSMA-avid osseous metastases (OR 1.11 per 0.1 units; p=0.50). Limitations include selection bias for patients able to receive both tests and the sample size.

CONCLUSIONS

Each 0.1-unit increase in GC score was associated with an approximate 40% increase in the odds of PSMA-avid lymph node involvement. These data suggest that patients with GC high risk might benefit from more nodal imaging and treatment intensification, potentially via pelvic nodal dissection, pelvic nodal irradiation, and/or the addition of chemohormonal agents.

PATIENT SUMMARY

Patients with higher genomic classifier scores were found to have more metastatic lymph node involvement on prostate-specific membrane antigen imaging.

[Radiation therapy of locally advanced prostate cancer]

The risk classification for localized prostate cancer is based on the groups "low", "intermediate", and "high-risk" prostate cancer. Following this established risk group definition, locally advanced prostate cancer (cT3/4N0M0) has to be classified as "high-risk" prostate cancer. Radical prostatectomy or high-dose radiotherapy, which is combined with androgen deprivation, are the only curative standard treatments for locally advanced prostate cancer. Particularly adequate radiation doses, modern radiotherapy techniques like IMRT/IGRT, as well as long-term androgen suppression are essential for an optimal treatment outcome. In combination with definitive radiotherapy, androgen deprivation therapy should be started neoadjuvant/simultaneous to radiotherapy and is recommended to be continued after radiotherapy. Previous data suggest that 2‑year long-term androgen deprivation in this setting may not be inferior to 3‑year long-term androgen deprivation in high-risk patients. An additional radiation therapy of the lymphatic pathways in men with cN0 locally advanced/high-risk prostate cancer is still a matter of research. Ongoing trials may define selected subgroups with a suggested benefit at its best.

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.

Risk factors for late bowel and bladder toxicities in NRG Oncology prostate cancer trials of high-risk patients: A meta-analysis of physician-rated toxicities

Purpose

A meta-analysis of sociodemographic variables and their association with late (>180 days from start of radiation therapy[RT]) bowel, bladder, and clustered bowel and bladder toxicities was conducted in patients with high-risk (clinical stages T2c-T4b or Gleason score 8-10 or prostate-specific antigen level >20) prostate cancer.

Methods and materials

Three NRG trials (RTOG 9202, RTOG 9413, and RTOG 9406) that accrued from 1992 to 2000 were used. Late toxicities were measured with the Radiation Therapy Oncology Group Late Radiation Morbidity Scale. After controlling for study, age, Karnofsky Performance Status, and year of accrual, sociodemographic variables were added to the model for each outcome variable of interest in a stepwise fashion using the Fine-Gray regression models with an entry criterion of 0.05.

Results

A total of 2432 patients were analyzed of whom most were Caucasian (76%), had a KPS score of 90 to 100 (92%), and received whole-pelvic RT+HT (67%). Of these patients, 13 % and 16% experienced late grade ≥2 bowel and bladder toxicities, respectively, and 2% and 3% experienced late grade ≥3 bowel and bladder toxicities, respectively. Late grade ≥2 clustered bowel and bladder toxicities were seen in approximately 1% of patients and late grade ≥3 clustered toxicities were seen in 2 patients (<1%). The multivariate analysis showed that patients who received prostate-only RT+HT had a lower risk of experiencing grade ≥2 bowel toxicities than those who received whole-pelvic RT+long-term (LT) HT (hazard ratio: 0.36; 95% confidence interval, 0.18-0.73; P = .0046 and hazard ratio: 0.43; 95% confidence interval, 0.23-0.80; P = .008, respectively). Patients who received whole-pelvic RT had similar chances of having grade ≥2 bowel or bladder toxicities no matter whether they received LT or short-term HT.

Conclusions

Patients with high-risk prostate cancer who receive whole-pelvic RT+LT HT are more likely to have a grade ≥2 bowel toxicity than those who receive prostate-only RT. LT bowel and bladder toxicities were infrequent. Future studies will need to confirm these findings utilizing current radiation technology and patient-reported outcomes.

Prognostic impact of nodal relapse in definitive prostate-only irradiation

BACKGROUND

Whole pelvic irradiation in prostate cancer patients might prevent metastatic spread of cancer cells through lymphatic drainages in patients eligible for definitive radiotherapy, but its use has declined in the last decades in favor of prostate-only irradiation (POI). The aim of our study is to assess the incidence of pelvic lymph nodal relapse and outcome in prostate cancer patients receiving POI.

MATERIALS AND METHODS

Data from 207 consecutive patients were collected. Clinical and treatment variables were collected. Biochemical relapse-free survival (BRFS), pelvic nodal relapse-free survival (PNRFS), distant metastasis-free survival (DMFS), disease-specific survival (DSS) and overall survival (OS) were calculated; analysis of prognostic variables was performed.

RESULTS

Five-year BRFS, PNRFS, DMFS, DSS and OS were, respectively, 90, 98, 96, 97 and 91%. On multivariate analysis, independent negative predictors of BRFS were Gleason score ≥ 7 (HR: 3.25) and PSA nadir ≥ 0.08 (HR: 4.86). Pelvic nodal relapse was not correlated to impaired outcome.

CONCLUSIONS

Lymph nodal pelvic relapse occurs in 2% of patients at 5 years and does not correlate with impaired outcome, suggesting the lack of theoretical benefit of a prophylactic nodal irradiation. Tumor biology and response to treatment are the main determinants of outcome.

Conformal Radiotherapy of Clinically Localized Prostate Cancer: Analysis of Rectal and Urinary Toxicity and Correlation with Dose-Volume Parameters

Aims and background

Rectal and urinary toxicities are the principal limiting factors in delivering a high target dose to patients affected by prostate cancer. The verification of such toxicity is an important step before starting a dose-escalation program. The present observational study reports on the acute and late rectal and urinary toxicity in relation with dose-volume parameters in 104 patients with localized prostate cancer treated with 3-dimensional conformal radiation therapy.

Methods and study design

One hundred and four patients with stage T1b-T3b prostate cancer were treated with three-dimensional conformal radiation therapy to a total dose of 74 Gy, 2 Gy per fraction. Rigid dose constraints were applied for rectum and bladder. Acute and late rectal and urinary toxicities were analyzed also in relation to dose-volume histograms. Biochemical relapse-free survival was defined according to the American Society of Therapeutic Radiation Oncology (ASTRO) criteria and to the RTOG-ASTRO Phoenix Consensus Conference Recommendations using the Kaplan-Meier method.

Results

No grade 3 toxicity was observed. Acute and late grade 2 toxicity rates were 5.8% and 9.0% for rectum and 12.5% and 2.0% for bladder, respectively. Rectal V70 influenced the occurrence of late grade 2 toxicity. A relationship between acute and late urinary toxicity was also found. After a median follow-up of 30 months (range, 20–50), the actuarial overall and biochemical relapse-free survival rates were 84% and 77%, respectively, with a significant difference between low-intermediate and high-risk patients.

Conclusions

Conformal radiotherapy to the dose of 74 Gy was administered with good compliance. The incidence of acute and late toxicity was relatively low in accord with our dose constraints. Rectal V70 proved to be a reliable prognosticator of late toxicity. Overall survival and biochemical relapse-free survival rates were more favorable for low and intermediate-risk and significantly less favorable for high-risk patients.

Clinical outcome and toxicity evaluation of simultaneous integrated boost pelvic IMRT/VMAT at different dose levels combined with androgen deprivation therapy in prostate cancer patients

Background

The role of dose escalation in patients receiving long-term androgen deprivation therapy (ADT) is still a controversial issue. The aim of the current study was to evaluate whether dose escalation for ≥76–80 Gy had any advantage in terms of biochemical disease-free survival (BDFS), distant metastasis-free survival (DMFS), or overall survival outcomes over the dose levels from 70 to <76 Gy.

Patients and methods

The study included a cohort of 24 patients classified with high- and intermediate-risk localized prostate cancer. All patients received ADT, starting at 4–6 months before radiation therapy and continued for a total period of 12–24 months in high-risk patients. The treatment plan was given in two phases. In the first phase, the nodal planning target volume (PTV) and the prostate PTV received 48.6 and 54 Gy, respectively, over 27 fractions. The treatment was applied through intensity-modulated radiation therapy or volumetric modulated arc therapy with a simultaneous integrated boost technique.

Results

More than half of the patients were in T3–T4 stage, 79.1% of the patients were in the high-risk category, and all patients received ADT. The rate of acute grade II gastrointestinal and genitourinary toxicities in all patients were 41.7% and 62.5%, respectively. The rate of freedom from grade II rectal toxicity at 2 years was 89% and 83% for patients treated with dose levels <76 and ≥76 Gy, respectively. The rate of BDFS at 2 years was 90% and 85% for doses <76 and ≥76 Gy, respectively. The DMFS at 2 years was 100% and 76% for dose levels <76 and ≥76 Gy, respectively.

Conclusion

In the current study, there were no significant differences in the BDFS and DMFS between patients treated with a dose of <76 and ≥76 Gy, including elective pelvic lymph nodes irradiation combined with ADT.

Incidental Dose to Pelvic Nodal Regions in Prostate-Only Radiotherapy

OBJECTIVES

Pelvic lymph nodal regions receive an incidental dose from conformal treatment of the prostate. This study was conducted to investigate the doses received by the different pelvic nodal regions with varying techniques used for prostate radiotherapy.

METHODS AND MATERIALS

Twenty patients of high-risk node-negative prostate cancer treated with intensity-modulated radiotherapy to the prostate alone were studied. Replanning was done for intensity-modulated radiotherapy, 3-dimensional conformal treatment, and 2-dimensional conventional radiotherapy with additional delineation of the pelvic nodal regions, namely, common iliac (upper and lower), presacral, internal iliac, obturator, and external iliac. Dose-volume parameters such as Dmean, D100%, D66%, D33%, V40, and V50 to each of the nodal regions were estimated for all patients.

RESULTS

The obturator nodes received the highest dose among all nodal regions. The mean dose received by obturator nodal region was 44, 29, and 22 Gy from 2-dimensional conventional radiotherapy, 3-dimensional conformal treatment, and intensity-modulated radiotherapy, respectively. The mean dose was significantly higher when compared between 2-dimensional conventional radiotherapy and 3-dimensional conformal treatment ( P < .001), 2-dimensional conventional radiotherapy and intensity-modulated radiotherapy ( P < .001), and 3-dimensional conformal treatment and intensity-modulated radiotherapy ( P < .001). The D33% of the obturator region was 64, 39, and 37 Gy from 2-dimensional conventional radiotherapy, 3-dimensional conformal treatment, and intensity-modulated radiotherapy, respectively. The dose received by all other pelvic nodal regions was low and not clinically relevant.

CONCLUSION

The incidental dose received by obturator regions is significant especially with 2-dimensional conventional radiotherapy and 3-dimensional conformal treatment techniques as used in the trials studying elective pelvic nodal irradiation. However, with intensity-modulated radiotherapy, this dose is lower, making elective pelvic irradiation more relevant. Advances in Knowledge: This study highlights that incidental dose received by obturator regions is significant especially with 2-dimensional conventional radiotherapy and 3-dimensional conformal treatment techniques.

Prostate cancer outcomes for men who present with symptoms at diagnosis

OBJECTIVE

To compare clinical features, treatments and outcomes in men with non-metastatic prostate cancer (PCa) according to whether they were referred for symptoms or elevated prostate-specific antigen (PSA) level.

PATIENTS AND METHODS

This study used data from the South Australia Prostate Cancer Clinical Outcomes Collaborative database; a multi-institutional clinical registry covering both the public and private sectors. We included all non-metastatic cases from 1998 to 2013 referred for urinary/prostatic symptoms or elevated PSA level. Multivariate Poisson regression was used to identify characteristics associated with symptomatic presentation and compare treatments according to reason for referral. Outcomes (i.e. overall survival, PCa-specific survival, metastasis-free survival and disease-free survival) were compared using multivariate Cox proportional hazards and competing risk regression.

RESULTS

Our analytical cohort consisted of 4 841 men with localized PCa. Symptomatic men had lower-risk disease (incidence ratio [IR] 0.70, 95% confidence interval [CI] 0.61-0.81 for high vs low risk), fewer radical prostatectomies (IR 0.64, CI: 0.56-0.75) and less radiotherapy (IR 0.86, CI: 0.77-0.96) than men presenting with elevated PSA level. All-cause mortality (hazard ratio [HR] 1.31, CI: 1.16-1.47), disease-specific mortality (HR 1.42, CI: 1.13-1.77) and risk of metastases (HR 1.36, CI: 1.13-1.64) were higher for men presenting with symptoms, after adjustment for other clinical characteristics; however, risk of disease progression did not differ (HR 0.90, CI: 0.74-1.07) amongst those treated curatively. Subgroup analyses indicated poorer PCa survival for symptomatic referral among men undergoing radical prostatectomy (HR 3.4, CI: 1.3-8.8), those aged >70 years (HR 1.4, CI: 1.0-1.8), men receiving private treatment (HR 2.1, CI: 1.3-3.3), those diagnosed via biopsy (HR 1.3, CI: 1.0-1.7) and those diagnosed before 2006 (HR 1.6, CI: 1.2-2.7).

CONCLUSION

Our results suggest that symptomatic presentation may be an independent negative prognostic indicator for PCa survival. More complete assessment of disease grade and extent, more definitive treatment and increased post-treatment monitoring among symptomatic cases may improve outcomes. Further research to determine any pathophysiological basis for poor outcomes in symptomatic men is warranted.