Focal Boost to the Intraprostatic Tumor in External Beam Radiotherapy for Patients With Localized Prostate Cancer: Results From the FLAME Randomized Phase III Trial

The use of a thin guide-wire for urethral definition in prostate SBRT treatments with Cyberknife

PURPOSE

To study and analyze the effect of the use of a thin guide-wire instead of a Foley catheter for urethral definition in prostate stereotactic body radiation therapy (SBRT) treatments and to compare treatment parameters in both situations.

MATERIAL AND METHODS

Thirty-seven prostate SBRT patients were employed in this study. A Foley catheter was employed in nine of them, and a guide-wire was employed in the other 28 patients. For each of the 28 patients in which the guide-wire was employed, a comparison between urethral positions in both situations was performed, allowing for a margin definition of the urethra when a Foley catheter was employed. Displacements of the prostate during treatment were obtained, allowing for an analysis of prostate positions in both situations. Also, different treatment parameters such as the number of treatment interruptions, couch movements performed, and x-rays needed were gathered.

RESULTS

Large differences between urethral positions can be found in the anterior-posterior (AP) directions compared to those in the lateral (LAT) direction. Differences are also larger in areas closer to the base of the prostate, where margins applied in the case of using a Foley catheter are 16 mm with a mean displacement of 6 mm in the posterior direction. No differences in the treatment parameters were found during treatment in both situations. The difference found in absolute prostate pitch rotations suggests that the Foley catheter provokes a shift of the prostate position, which does not occur when employing the guide-wire.

CONCLUSIONS

Foley catheters shift the urethral position, making them a wrong surrogate of the urethra when no catheters are present. The margins needed to assess uncertainties introduced by the use of a Foley catheter are larger than those usually applied. The use of a Foley catheter did not present any additional difficulty during treatment delivery in terms of images employed or interruptions produced.

Safety and efficacy associated with single-fraction high-dose-rate brachytherapy in localized prostate cancer: a systematic review and meta-analysis

OBJECTIVE

Although single-fraction high-dose-rate brachytherapy (SFHDR) for localized prostate cancer has been tried in clinical trials, relevant medical evidence is currently lacking. It is necessary to systematically analyze the safety and efficacy of SFHDR.

METHODS

Comprehensive and systematic searches for eligible studies were performed in PubMed, Embase, and the Cochrane Library databases. The primary endpoints included safety and efficacy, represented by toxic effects and biochemical recurrence-free survival (bRFS), respectively. The proportion rates were used as the effect measure for each study and were presented with corresponding 95% confidence intervals (CI) and related 95% prediction interval (PI). Restricted maximum-likelihood estimator (REML) and the Hartung-Knapp method were used in the meta-analysis.

RESULTS

Twenty-five studies met the inclusion criteria for quantitative analysis, including 1440 patients. The median age of patients was 66.9 years old (62-73 years old) and the median follow-up was 47.5 months (12-75 months). The estimates of cumulative occurrence for severe gastrointestinal (GI) and genitourinary (GU) toxic effects were 0.1% (95% CI 0-0.2%) and 0.4% (95% CI 0-1.2%), and for grade 2 toxic effects were 1.6% (95% CI 0.1-4.7%) and 17.1% (95% CI 5.4-33.5%), respectively. The estimate of 3‑year bRFS was 87.5% (95% CI 84.4-90.3%) and 71.0% (95% CI 63.0-78.3%) for 5‑year bRFS. The pooled bRFS rates for low-risk patients were 99.0% (95% CI 85.2-100.0%) at 3 years and 80.9% (95% CI 75.4-85.9%) at 5 years, and the risk group was found to be statistically correlated with bRFS (3-year bRFS, P < 0.01; 5‑year bRFS, P = 0.04).

CONCLUSION

SFHDR is associated with favorable tolerability and suboptimal clinical benefit in patients with localized prostate cancer. Ongoing and planned high-quality prospective studies are necessary to verify its safety and efficacy.

Detecting and Locating the Site of Local Relapse Using 18F-PSMA-1007 Imaging After Primary Treatment of 135 Prostate Cancer Patients-Potential Impact on PSMA-Guided Radiation Therapy

PURPOSE

Due to limited imaging options, the visualization of a local relapse of prostate cancer used to pose a considerable challenge. However, since the integration of ¹⁸F-PSMA-1007-PET/CT into the clinic, a relapsed tumor can now easily be detected by hybrid imaging. The present study aimed to evaluate and map the allocate relapse in a large cohort of prostate cancer patients focusing on individual patient management conclusions for radiation therapy.

PROCEDURES

The current study included 135 men with prostate cancer after primary treatment who underwent ¹⁸F-PSMA-1007-PET/CT due to biochemical relapse detecting a local relapse. Imaging data were reassessed and analyzed with regard to relapse locations. For the correlation of tumor foci with clinical data, we used binary logistic regression models as well as the Kruskal-Wallis test and Mann-Whitney test.

RESULTS

In total, 69.6% of all patients (mean age: 65 years) underwent prostatectomy while 30.4% underwent radiation therapy. PET imaging detected most frequently a unifocal relapse (72.6%). There was a statistically significantly higher rate of ipsilateral cases among the relapsed tumors. Comparing both treatment approaches, tumors relapsed most commonly within the posterior region after surgery and transition/peripheral zone after radiation therapy, respectively.

CONCLUSIONS

The present study confirms that ¹⁸F-PSMA-1007-PET/CT is highly suitable for the localization and allocation of a local relapse in patients with prostate cancer. The data enable further optimizing dose prescriptions and target volume delineations of radiation therapy in the future.

An Updated Analysis of the Survival Endpoints of ASCENDE-RT

PURPOSE

Using the primary endpoint of time to biochemical progression (TTP), Androgen Suppression Combined with Elective Nodal and Dose Escalated Radiation Therapy (ASCENDE-RT) randomized National Comprehensive Cancer Network patients with intermediate and high-risk prostate cancer to low-dose-rate brachytherapy boost (LDR-PB) or dose-escalated external beam boost (DE-EBRT). Randomization to the LDR-PB arm resulted in a 2-fold reduction in biochemical progression compared with the DE-EBRT group at a median follow-up of 6.5 years (P < .001). Herein, the primary endpoint and secondary survival endpoints of the ASCENDE-RT trial are updated at a 10-year median follow-up.

METHODS

Patients were randomly assigned to either the LDR-PB or the DE-EBRT arm (1:1). All patients received 1 year of androgen deprivation therapy and 46 Gy in 23 fractions of pelvic RT. Patients in the DE-EBRT arm received an additional 32 Gy in 16 fractions, and those in the LDR-PB arm received an ¹²⁵I implant prescribed to a minimum peripheral dose of 115 Gy. Two hundred patients were randomized to the DE-EBRT arm and 198 to the LDR-PB arm.

RESULTS

The 10-year Kaplan-Meier TTP estimate was 85% ± 5% for LDR-PB compared with 67% ± 7% for DE-EBRT (log rank P < .001). Ten-year time to distant metastasis (DM) was 88% ± 5% for the LDR-PB arm and 86% ± 6% for the DE-EBRT arm (P = .56). There were 117 (29%) deaths. Ten-year overall survival (OS) estimates were 80% ± 6% for the LDR-PB arm and 75% ± 7% for the DE-EBRT arm (P = .51). There were 30 (8%) patients who died of prostate cancer: 12 (6%) in the LDR-PB arm, including 2 treatment-related deaths, and 18 (9%) in the DE-EBRT arm.

CONCLUSIONS

Men randomized to the LDR-PB boost arm of the ASCENDE-RT trial continue to experience a large advantage in TTP compared with those randomized to the DE-EBRT arm. ASCENDE-RT was not powered to detect differences in its secondary survival endpoints (OS, DM, and time to prostate cancer-specific death) and none are apparent.

Treatment planning comparison of high-dose-rate brachytherapy vs. robotic and conventional stereotactic body radiotherapy for ultrahypofractionated treatment of prostate cancer

Background and purpose

Ultrahypofractionated radiation therapy is increasingly used in the treatment of prostate cancer. High-dose-rate brachytherapy (HDR-BT) and stereotactic body radiotherapy (SBRT) are representative methods of ultrahypofractionation. This study was performed to compare clinically applied treatment plans for patients who had been treated using HDR-BT vs. conventional or robotic SBRT.

Materials and methods

Calculated dose-volume indices between HDR-BT without a perirectal spacer (n = 20), robotic SBRT without a spacer (n = 40), and conventional (non-robotic) SBRT with a spacer (n = 40) were compared. Percentages against the prescription dose regarding the planning target volume (PTV), bladder, rectum, and urethra were statistically compared.

Results

The D50% of the PTV with HDR-BT (140.5% ± 4.9%) was significantly higher than that with robotic or conventional SBRT (116.2% ± 1.6%, 101.0% ± 0.4%, p < 0.01). The D2cm³ of the bladder with HDR-BT (65.6% ± 6.4%) was significantly lower than those with SBRT (105.3% ± 2.9%, 98.0% ± 1.3%, p < 0.01). The D2cm³ of the rectum with HDR-BT (60.6% ± 6.2%) was also significantly lower than those with SBRT (85.1% ± 8.8%, 70.4% ± 9.6%, p < 0.01). By contrast, the D0.1cm³ of the urethra with HDR-BT (117.1% ± 3.6%) was significantly higher than those with SBRT (100.2% ± 0.7%, 104.5% ± 0.6%, p < 0.01).

Conclusions

HDR-BT could administer a higher dose to the PTV and a lower dose to the bladder and rectum, at the cost of a slightly higher dose to the urethra compared with SBRT.

Stereotactic Magnetic Resonance-Guided Adaptive and Non-Adaptive Radiotherapy on Combination MR-Linear Accelerators: Current Practice and Future Directions

Stereotactic body radiotherapy (SBRT) is an effective radiation therapy technique that has allowed for shorter treatment courses, as compared to conventionally dosed radiation therapy. As its name implies, SBRT relies on daily image guidance to ensure that each fraction targets a tumor, instead of healthy tissue. Magnetic resonance imaging (MRI) offers improved soft-tissue visualization, allowing for better tumor and normal tissue delineation. MR-guided RT (MRgRT) has traditionally been defined by the use of offline MRI to aid in defining the RT volumes during the initial planning stages in order to ensure accurate tumor targeting while sparing critical normal tissues. However, the ViewRay MRIdian and Elekta Unity have improved upon and revolutionized the MRgRT by creating a combined MRI and linear accelerator (MRL), allowing MRgRT to incorporate online MRI in RT. MRL-based MR-guided SBRT (MRgSBRT) represents a novel solution to deliver higher doses to larger volumes of gross disease, regardless of the proximity of at-risk organs due to the (1) superior soft-tissue visualization for patient positioning, (2) real-time continuous intrafraction assessment of internal structures, and (3) daily online adaptive replanning. Stereotactic MR-guided adaptive radiation therapy (SMART) has enabled the safe delivery of ablative doses to tumors adjacent to radiosensitive tissues throughout the body. Although it is still a relatively new RT technique, SMART has demonstrated significant opportunities to improve disease control and reduce toxicity. In this review, we included the current clinical applications and the active prospective trials related to SMART. We highlighted the most impactful clinical studies at various tumor sites. In addition, we explored how MRL-based multiparametric MRI could potentially synergize with SMART to significantly change the current treatment paradigm and to improve personalized cancer care.

Virtual HDR Boost for Prostate Cancer: Rebooting a Classic Treatment Using Modern Tech

Prostate cancer (PC) is the most common malignancy in men. Internal radiotherapy (brachytherapy) has been used to treat PC successfully for over a century. In particular, there is level-one evidence of the benefits of using brachytherapy to escalate the dose of radiotherapy compared with standard external beam radiotherapy approaches. However, the use of PC brachytherapy is declining, despite strong evidence for its improved cancer outcomes. A method using external beam radiotherapy known as virtual high-dose-rate brachytherapy boost (vHDRB) aims to noninvasively mimic a brachytherapy boost radiation dose plan. In this review, we consider the evidence supporting brachytherapy boosts for PC and the continuing evolution of vHDRB approaches, culminating in the current generation of clinical trials, which will help define the role of this emerging modality.

Brachytherapy boost improves survival and decreases risk of developing distant metastases compared to external beam radiotherapy alone in intermediate and high risk group prostate cancer patients

BACKGROUND AND PURPOSE

Despite several prospective trials showing a clinical benefit of combining external beam radiotherapy (EBRT) with brachytherapy boost (BTB) for the treatment of intermediate- and high-risk prostate cancer (PCa) patients, none of these trials were designed to test for a survival difference. In this study, we aimed to collect a large multi-institutional database to determine whether BT boost was associated with a statistically significant improvement in survival and a reduction of distant metastases based on real-world data.

MATERIAL AND METHODS

We collected the data of patients treated for intermediate- or high-risk PCa with definitive EBRT or BTB, with or without androgen deprivation therapy (ADT), between January 2003 and December 2014 at two tertiary institutions. The statistical endpoints included overall survival (OS), freedom from distant metastases (FFDM), and metastases-free survival (MFS). The impact of treatment modality was assessed using Cox regression models and log-rank testing after one-to-one propensity score matching.

RESULTS

A total of 1641 patients treated with EBRT (n=1148) or high-dose-rate BTB (n=493) were analyzed. The median survival and clinical follow-up were 117.8 (IQR 78-143.3) and 60.7 months, respectively. The radiotherapy modality (BTB) remained an independent prognostic factor for OS (HR 0.75; 95% CI 0.63-0.88; p<0.001), FFDM (HR 0.54; 95% CI 0.4-0.73; p<0.001), and MFS (HR 0.72; 95% CI 0.61-0.85; p<0.001). After propensity score matching, the remaining 986 patients were well-balanced in terms of age, maximum PSA, ISUP grade group, and TNM T stage. OS (p=0.001), FFDM (p<0.001) and MFS (p<0.001) were significantly higher in the BTB group.

CONCLUSIONS

There is a strong positive association between BTB and OS, FFDM, and MFS in PCa patients treated with definitive RT for intermediate- or high-risk PCa.

Toxicity of dose-escalated radiotherapy up to 84 Gy for prostate cancer

PURPOSE

The outcome of radiotherapy (RT) for prostate cancer (PCA) depends on the delivered dose. While the evidence for dose-escalated RT up to 80 gray (Gy) is well established, there have been only few studies examining dose escalation above 80 Gy. We initiated the present study to assess the safety of dose escalation up to 84 Gy.

METHODS

In our retrospective analysis, we included patients who received dose-escalated RT for PCA at our institution between 2016 and 2021. We evaluated acute genitourinary (GU) and gastrointestinal (GI) toxicity as well as late GU and GI toxicity.

RESULTS

A total of 86 patients could be evaluated, of whom 24 patients had received 80 Gy and 62 patients 84 Gy (35 without pelvic and 27 with pelvic radiotherapy). Regarding acute toxicities, no > grade 2 adverse events occurred. Acute GU/GI toxicity of grade 2 occurred in 12.5%/12.5% of patients treated with 80 Gy, in 25.7%/14.3% of patients treated with 84 Gy to the prostate only, and in 51.9%/12.9% of patients treated with 84 Gy and the pelvis included. Late GU/GI toxicity of grade ≥ 2 occurred in 4.2%/8.3% of patients treated with 80 Gy, in 7.1%/3.6% of patients treated with 84 Gy prostate only, and in 18.2%/0% of patients treated with 84 Gy pelvis included (log-rank test p = 0.358).

CONCLUSION

We demonstrated that dose-escalated RT for PCA up to 84 Gy is feasible and safe without a significant increase in acute toxicity. Further follow-up is needed to assess late toxicity and survival.

Beyond diagnosis: is there a role for radiomics in prostate cancer management?

The role of imaging in pretreatment staging and management of prostate cancer (PCa) is constantly evolving. In the last decade, there has been an ever-growing interest in radiomics as an image analysis approach able to extract objective quantitative features that are missed by human eye. However, most of PCa radiomics studies have been focused on cancer detection and characterisation. With this narrative review we aimed to provide a synopsis of the recently proposed potential applications of radiomics for PCa with a management-based approach, focusing on primary treatments with curative intent and active surveillance as well as highlighting on recurrent disease after primary treatment. Current evidence is encouraging, with radiomics and artificial intelligence appearing as feasible tools to aid physicians in planning PCa management. However, the lack of external independent datasets for validation and prospectively designed studies casts a shadow on the reliability and generalisability of radiomics models, delaying their translation into clinical practice.Key points• Artificial intelligence solutions have been proposed to streamline prostate cancer radiotherapy planning.• Radiomics models could improve risk assessment for radical prostatectomy patient selection.• Delta-radiomics appears promising for the management of patients under active surveillance.• Radiomics might outperform current nomograms for prostate cancer recurrence risk assessment.• Reproducibility of results, methodological and ethical issues must still be faced before clinical implementation.

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.

Multimodality Therapies for Localized Prostate Cancer

PURPOSE OF REVIEW

Multimodality therapy including radical prostatectomy, radiation therapy, and hormone therapy are frequently deployed in the management of localized prostate cancer. We sought to perform a critical appraisal of the most contemporary literature focusing on the multimodality management of localized prostate cancer.

RECENT FINDINGS

Men who are ideal candidates for multimodality therapy include those with unfavorable intermediate-risk disease, high-risk disease, and very high-risk disease. Enhancements in both systemic agents (including second-generation antiandrogens) as well as localized therapies (such as stereotactic body radiotherapy and brachytherapy) are refining the optimal balance between the use of systemic and local therapies for localized prostate cancer. Genomic predictors are emerging as critical tools for more precisely allocating treatment intensification with multimodality therapies as well as treatment de-intensification. Close collaboration among medical oncologists, surgeons, and radiation oncologists will be critical for coordinating evidence-based multimodality therapies when clearly indicated and for supporting shared decision-making in areas where the evidence is mixed.

Outcomes following brachytherapy boost for intermediate- and high-risk prostate cancer: A retrospective bicenter study by the SFRO brachytherapy group

INTRODUCTION

Radiotherapy dose escalation improves biochemical control in intermediate- or high-risk prostate cancer. Brachytherapy boost was shown to further improve biochemical control compared to radiotherapy alone in three randomized trials. The SFRO brachytherapy group sought to evaluate the efficacy and toxicity of BT-boost for intermediate and high-risk prostate cancer in real life, and to determine prognostic factors for efficacy and toxicity.

MATERIAL AND METHOD

A retrospective study was conducted, including all patients with intermediate- or high-risk prostate cancer treated with a combination of external beam radiotherapy (EBRT) and high dose-rate brachytherapy boost (HDR-BB), from 2006 until December 2019 at two centers. Patient characteristics, initial disease, treatment and follow-up were collected.

RESULTS

709 patients from two centers were analyzed given a short follow-up in the other centers. Out of those, 277 were intermediate risk (170 favorable and 107 unfavorable) and 432 were high risk. The median EBRT and HDR-BB doses were 46 Gy (35-50) and 14 Gy (10-20). After a median follow-up of 62 months, biochemical control at 5 years was 87.5 % for the overall population, 91 % and 85 % for intermediate- and high-risk cancers, respectively. At 5 years, biochemical and clinical relapse-free survival, metastasis-free survival and local control rates were 83 %, 90 % and 97 % respectively. 5-years overall survival was 94 %. Late grade 2 or higher GU or GI toxicity was found in 36 patients (5 %) and 9 patients (1.3 %).

CONCLUSION

This bicenter analysis shows the efficacy and tolerability of HDR-BB as a complement to external radiotherapy. Further improvements such as combination with new hormonal agents or new brachytherapy-radiotherapy fractionation regimens are warranted to improve further the outcomes and therapeutic ratio.

Advancing the treatment of localized prostate cancer with MR-guided radiotherapy

External beam radiotherapy (EBRT) is an important cornerstone in the treatment of localized prostate cancer. Current image-guided radiotherapy (IGRT) techniques allow for more accurate and precise delivery of radiation treatment by the use of imaging before each fraction. Magnetic resonance guided radiotherapy (MRgRT) is the next step in IGRT with hybrid systems combining linear accelerators with MRI-scanners. With MRgRT, it is possible to visualize pelvic anatomy in great detail and subsequently perform replanning of the radiation dose distribution before each radiotherapy fraction. This technique has the potential to increase the therapeutic window of EBRT, by improved normal tissue sparing due to margin reduction and more accurate target dose delivery. This is particularly promising for prostate cancer, with its biology lending itself to ultra-hypofractionation, reducing radiotherapy treatment to as little as five fractions. Also, recent studies have shown that focal dose escalation to the intraprostatic tumor to high ablative doses can substantially increase disease-free survival. In this article, we discuss these unique opportunities as well as the potential future benefits of MRgRT in prostate cancer treatment.

ESTRO-ACROP recommendations for evidence-based use of androgen deprivation therapy in combination with external-beam radiotherapy in prostate cancer

BACKGROUND AND PURPOSE

There is no consensus concerning the appropriate use of androgen deprivation therapy (ADT) during primary and postoperative external-beam radiotherapy (EBRT) in the management of prostate cancer (PCa). Thus, the European Society for Radiotherapy and Oncology (ESTRO) Advisory Committee for Radiation Oncology Practice (ACROP) guidelines seeks to present current recommendations for the clinical use of ADT in the various indications of EBRT.

MATERIAL AND METHODS

A literature search was conducted in MEDLINE PubMed that evaluated EBRT and ADT in prostate cancer. The search focused on randomized, Phase II and III trials published in English from January 2000 to May 2022. In case topics were addressed in the absence of Phase II or III trials, recommendations were labelled accordingly based on the limited body of evidence. Localized PCa was classified according to D'Amico et al. classification in low-, intermediate and high risk PCa. The ACROP clinical committee identified 13 European experts who discussed and analyzed the body of evidence concerning the use of ADT with EBRT for prostate cancer.

RESULTS

Key issues were identified and are discussed: It was concluded that no additional ADT is recommended for low-risk prostate cancer patients, whereas for intermediate- and high-risk patients four to six months and two to three years of ADT are recommended. Likewise, patients with locally advanced prostate cancer are recommended to receive ADT for two to three years and when ≥ 2 high-risk factors (cT3-4, ISUP grade ≥ 4 or PSA ≥ 40 ng/ml) or cN1 is present ADT for three years plus additional Abiraterone for two years is recommended. For postoperative patients no ADT is recommended for adjuvant EBRT in pN0 patients whereas for pN1 patients adjuvant EBRT with long-term ADT is performed for at least 24 to 36 months. In the setting of salvage EBRT ADT is performed in biochemically persistent PCa patients with no evidence of metastatic disease. Long-term ADT (24 months) is recommended in pN0 patients with high risk of further progression (PSA ≥ 0.7 ng/ml and ISUP grade group ≥ 4) and a life expectancy of over ten years, whereas short-term ADT (6 months) is recommended in pN0 patients with lower risk profile (PSA < 0.7 ng/ml and ISUP grade group 4). Patients considered for ultra-hypofractionated EBRT as well as patients with image based local recurrence within the prostatic fossa or lymph node recurrence should participate in appropriate clinical trials evaluating the role of additional ADT.

CONCLUSION

These ESTRO-ACROP recommendations are evidence-based and relevant to the use of ADT in combination with EBRT in PCa for the most common clinical settings.

A Contemporary Report of Low-Dose-Rate Brachytherapy for Prostate Cancer Using MRI for Risk Stratification: Disease Outcomes and Patient-Reported Quality of Life

PURPOSE

We examined a prospective consecutive cohort of low dose rate (LDR) brachytherapy for prostate cancer to evaluate the efficacy of monotherapy for unfavorable-intermediate risk (UIR) disease, and explore factors associated with toxicity and quality of life (QOL).

METHODS

149 men with prostate cancer, including 114 staged with MRI, received Iodine-125 brachytherapy alone (144-145 Gy) or following external beam radiation therapy (110 Gy; EBRT). Patient-reported QOL was assessed by the Expanded Prostate Index Composite (EPIC) survey, and genitourinary (GU) and gastrointestinal (GI) toxicity were prospectively recorded (CTC v4.0). Global QOL scores were assessed for decline greater than the minimum clinically important difference (MCID). Univariate analysis (UVA) was performed, with 30-day post-implant dosimetry covariates stratified into quartiles. Median follow-up was 63 mo.

RESULTS

Men with NCCN low (n = 42) or favorable-intermediate risk (n = 37) disease were treated with brachytherapy alone, while most with high-risk disease had combined EBRT (n = 17 of 18). Men with UIR disease (n = 52) were selected for monotherapy (n = 42) based on clinical factors and MRI findings. Freedom from biochemical failure-7 yr was 98%. Of 37 men with MRI treated with monotherapy for UIR disease, all 36 men without extraprostatic extension were controlled. Late Grade 2+/3+ toxicity occurred in 55/3% for GU and 8/2% for GI, respectively. Fifty men were sexually active at baseline and had 2 yr sexual data; 37 (74%) remained active at 2 yr. Global scores for urinary incontinence (UC), urinary irritation/obstruction (UIO), bowel function, and sexual function (SF) showed decreases greater than the MCID (p < 0.05) in UC at 2 mo, UIO at 2 and 6 mo, and SF at 2-24 mo, and >5 yr. Analysis did not reveal any significant associations with any examined rectal or urethral dosimetry for late toxicity or QOL.

CONCLUSION

Disease outcomes and patient-reported QOL support LDR brachytherapy, including monotherapy for UIR disease.

Long-Term Outcomes of Stereotactic Body Radiotherapy (SBRT) for Intraprostatic Relapse after Definitive Radiotherapy for Prostate Cancer: Patterns of Failure and Association between Volume of Irradiation and Late Toxicity

The aim of this retrospective study was to assess the adverse effects and outcomes of salvage re-irradiation with stereotactic body radiotherapy (sSBRT) for local recurrence of prostate cancer (PCa) after definitive radiotherapy (RT). The study was focused on the adverse effects and prognostic factors for treatment toxicity, followed by an analysis of patterns of failure and survival. Patients treated with sSBRT between 2012 and 2020 at a tertiary institution were included. The exclusion criteria were a primary or salvage radical prostatectomy or a palliative sSBRT dose. Patients with oligorecurrence were eligible if all metastatic lesions were treated locally with curative intent. The Kaplan-Meier method was used to estimate time to grade ≥ 3 toxicity, local control (LC), freedom from distant metastases (FFDM), progression-free survival (PFS), biochemical control (BC) and overall survival (OS). The differences between groups (focal vs. whole-gland sSBRT) were compared using the log-rank test. The Cox proportional hazards model was used to assess prognostic factors for the listed endpoints. A total of 56 patients with a median age of 70.9 years and a median follow-up of 38.6 months were included in the analysis. The majority of them received local sSBRT only (45; 80.4%), while the rest were simultaneously treated for oligometastases (11; 19.6%). Overall, 18 (32.1%) patients experienced any grade ≥ 3 toxicity, including 1 (6.7%) patient who received focal sSBRT, and 17 (41.5%) patients treated with whole-gland sSBRT. The Planning Target Volume (per cc; HR 1.01; 95% CI 1-1.02; p = 0.025) and use of ADT (yes vs. no; HR 0.35; 95%CI 0.13-0.93; p = 0.035) were independent prognostic factors for the risk of grade ≥ 3 toxicity. The estimated rate of grade ≥ 3 adverse events was significantly higher (43.8% vs. 7.1% at 2 years; p = 0.006), and there was no improvement in the LC (92.9% vs. 85.3% at 2 years; p = 0.759) in patients treated with whole-gland sSBRT compared to focal sSBRT. The 2- and 5-year LC were 87.6% and 47.9%, respectively; the 2- and 5-year FFDM were 72.7% and 42.8%, respectively; and the 2- and 5-year PFS were 67.9% and 28.7%, respectively. The primary pattern of failure was distant metastasis. The sSBRT for local recurrence of PCa after definitive RT was associated with a high risk of severe grade ≥ 3 toxicity, which significantly increased with the volume and extent of re-irradiation.

Two-fraction stereotactic ablative radiotherapy with simultaneous boost to MRI-defined dominant intra-prostatic lesion - Results from the 2SMART phase 2 trial

PURPOSE

This is the first report of the 2SMART Phase II trial evaluating the safety of two-fraction stereotactic ablative radiotherapy (SABR) with focal boost to magnetic resonance imaging (MRI) defined dominant intra-prostatic lesion (DIL) for localised prostate cancer.

MATERIALS AND METHODS

Men with low or intermediate risk prostate cancer were eligible for the study. The gross tumour volume (GTV) was MRI-defined DIL, and the clinical target volume (CTV) was entire prostate gland. The planning target volume (PTV) was a 2 mm expansion anteroposterior and lateral, and 2.5 mm superoinferior. The prescribed dose was 32 Gy to GTV, and 26 Gy to CTV. Primary endpoint was minimal clinically important change (MCIC) in quality of life (QOL) within 3-months of SABR, assessed using the EPIC-26 questionnaire. Secondary endpoints were acute and late toxicities (assessed using CTCAEv4), PSA nadir, and biochemical failure (based on Phoenix criteria).

RESULTS

Thirty men were enrolled in the study - 2 (7%) had low-risk and 28 (93%) had intermediate risk prostate cancer. The median follow-up was 44 months (range:39-49 months). The median PSA nadir was 0.25 ng/mL, with median time to nadir of 37 months. One patient (3%) had biochemical failure at 44 months post-treatment. Ten (33%), six (20%), and three (10%) men had acute MCIC in urinary, bowel, and sexual QOL domains respectively. No acute or late grade ≥ 3 urinary or bowel toxicities were observed.

CONCLUSION

This novel protocol of two-fraction prostate SABR with MRI-defined DIL boost is a safe approach for dose-escalation, with minimal impact on acute QOL and no grade ≥ 3 toxicities.

Standard and Hypofractionated Dose Escalation to Intraprostatic Tumor Nodules in Localized Prostate Cancer: 5-Year Efficacy and Toxicity in the DELINEATE Trial

PURPOSE

Our purpose was to report 5-year efficacy and toxicity of intraprostatic lesion boosting using standard and hypofractionated radiation therapy.

METHODS AND MATERIALS

DELINEATE (ISRCTN 04483921) is a single center phase 2 multicohort study including standardly fractionated (cohort A: 74 Gy/37F to prostate and seminal vesicles [PSV]; cohort C 74 Gy/37F to PSV plus 60 Gy/37F to pelvic lymph nodes) and moderately hypofractionated (cohort B: 60 Gy/20F to PSV) prostate intensity-modulated radiation therapy patients with National Comprehensive Cancer Network intermediate/high-risk disease. Patients received an integrated boost of 82 Gy (cohorts A and C) or 67 Gy (cohort B) to multiparametric magnetic resonance imaging identified lesion(s). Primary endpoint was late Radiation Therapy Oncology Group (RTOG) gastrointestinal (GI) toxicity at 1 year. Secondary endpoints were acute and late toxicity (clinician and patient reported) and freedom from biochemical/clinical failure at 5 years.

RESULTS

Two hundred and sixty-five men were recruited and 256 were treated (55 cohort A, 153 cohort B, and 48 cohort C). Median follow-up for each cohort was >5 years. Cumulative late RTOG grade 2+ GI toxicity at 1 year was 3.6% (95% confidence interval [CI], 0.9%-13.8%) (cohort A), 7.2% (95% CI, 4%-12.6%) (cohort B), and 8.4% (95% CI, 3.2%-20.8%) (cohort C). Cumulative late RTOG grade 2+ GI toxicity to 5 years was 12.8% (95% CI, 6.3%-25.1%) (cohort A), 14.6% (95% CI, 9.9%-21.4%) (cohort B), and 20.7% (95% CI, 11.2%-36.2%) (cohort C). Cumulative RTOG grade 2+ genitourinary toxicity to 5 years was 12.9% (95% CI, 6.4%-25.2%) (cohort A), 18.2% (95% CI, 12.8%-25.4%) (cohort B), and 18.2% (95% CI, 9.5%-33.2%) (cohort C). Five-year freedom from biochemical/clinical failure was 98.2% (95% CI, 87.8%-99.7%) (cohort A), 96.7% (95% CI, 91.3%- 98.8%) (cohort B), and 95.1% (95% CI, 81.6-98.7%) (cohort C).

CONCLUSIONS

The DELINEATE trial has shown safety, tolerability, and feasibility of focal boosting in 20 or 37 fractions. Efficacy results indicate a low chance of prostate cancer recurrence 5 years after radiation therapy. Evidence from ongoing phase 3 randomized trials is awaited.

SBRT focal dose intensification using an MR-Linac adaptive planning for intermediate-risk prostate cancer: An analysis of the dosimetric impact of intra-fractional organ changes

INTRODUCTION

Using an magnetic resonance linear accelerator (MR-Linac) may improve the precision of visible tumor boosting with ultra-hypofractionation by accounting for daily positional changes in the target and organs at risk (OAR).

PATIENTS AND METHODS

Fifteen patients with prostate cancer and an MR-detected dominant lesion were treated on the MR-Linac with stereotactic body radiation (SBRT) to 40 Gy in 5 fractions, boosting the gross tumor volume (GTV) to 45 Gy with daily adaptive planning. Imaging was acquired again after initial planning (verification scan), and immediately after treatment (post-treatment scan). Prior to beam-on, additional adjustments were made on the verification scan. Contours were retrospectively adjusted on verification and post-treatment scans, and the daily plan recalculated on these scans to estimate the true dose delivered.

RESULTS

The median prostate D95% for plan 1, 2 and 3 was 40.3 Gy, 40.5 Gy and 40.3 Gy and DIL D95% was 45.7 Gy, 45.2 Gy and 44.6 Gy, respectively. Bladder filling was associated with reduced GTV coverage (p = 0.03, plan 1 vs 2) and prostate coverage (p = 0.03, plan 2 vs 3). The D0.035 cc constraint was exceeded on verification and post-treatment plans in 24 % and 33 % of fractions for the urethra, 31 % and 45 % for the bladder, and 35 % and 25 % for the rectum, respectively.

CONCLUSION

MR-Linac guided, daily adaptive SBRT with focal boosting of the GTV yields acceptable planned and delivered dosimetry. Adaptive planning with a MR-Linac may reliably deliver the prescribed dose to the intended tumor target.

A Phase I Trial of Neoadjuvant Stereotactic Body Radiotherapy Prior to Radical Prostatectomy for Locally Advanced Prostate Cancer

PURPOSE

Men with locally advanced prostate cancer who undergo radical prostatectomy (RP) often develop recurrence and require postoperative radiotherapy. We aimed to determine the safety of neoadjuvant stereotactic body radiotherapy (SBRT) before RP in this population.

METHODS AND PATIENTS

A single-institution phase 1 trial (NCT02946008) of men with high-risk or node-positive prostate cancer were enrolled between March and October 2017. The primary endpoint was to determine the maximum tolerated dose of SBRT based on a composite 30-day post-RP toxicity goal of ≤28% of patients experiencing a dose-limiting toxicity (DLT). Secondary outcomes included toxicity, efficacy, and multiple quality of life (QoL) inventories. SBRT (30-35 Gy/5 fractions) was delivered to the prostate and seminal vesicles, and 25 Gy/5 fractions to the pelvic lymph nodes. RP was performed for a median of 6 weeks post-SBRT. Hormone therapy was not allowed.

RESULTS

Median follow-up was 40 months (range, 33-44). Twenty-five percent of the patients (n = 4) experienced a DLT within 30 days post-RP; however, the trial was stopped early (n = 16 of planned 38 patients) owing to the proportion and severity of the late adverse events. Post-RP grade 3 genitourinary and gastrointestinal toxicities occurred in 75% (n = 12) and 25% (n = 4) of patients, respectively. Two patients required cystectomy and urinary diversion ≥2 years post-RP. At 24 months post-RP, 75% (n = 12) of men used ≥1 pad/d and 0% had erections suitable for intercourse. Surgical margins were negative in all patients and 31% (n = 5) had complete or partial (pre-RP) MRI-response to SBRT. Three-year biochemical recurrence and distant metastasis were 45% (95% CI, 5%-68%) and 28% (95% CI, 0%-49%), respectively.

CONCLUSIONS

Neoadjuvant SBRT followed by RP resulted in unacceptably high toxicity and severe QoL declines.

Genomic Classifiers in Personalized Prostate Cancer Radiation Therapy Approaches: A Systematic Review and Future Perspectives Based on International Consensus

Current risk-stratification systems for prostate cancer (PCa) do not sufficiently reflect the disease heterogeneity. Genomic classifiers (GC) enable improved risk stratification after surgery, but less data exist for patients treated with definitive radiation therapy (RT) or RT in oligo-/metastatic disease stages. To guide future perspectives of GCs for RT, we conducted (1) a systematic review on the evidence of GCs for patients treated with RT and (2) a survey of experts using the Delphi method, addressing the role of GCs in personalized treatments to identify relevant fields of future clinical and translational research. We performed a systematic review and screened ongoing clinical trials on ClinicalTrials.gov. Based on these results, a multidisciplinary international team of experts received an adapted Delphi method survey. Thirty-one and 30 experts answered round 1 and round 2, respectively. Questions with ≥75% agreement were considered relevant and included in the qualitative synthesis. Evidence for GCs as predictive biomarkers is mainly available to the postoperative RT setting. Validation of GCs as prognostic markers in the definitive RT setting is emerging. Experts used GCs in patients with PCa with extensive metastases (30%), in postoperative settings (27%), and in newly diagnosed PCa (23%). Forty-seven percent of experts do not currently use GCs in clinical practice. Expert consensus demonstrates that GCs are promising tools to improve risk-stratification in primary and oligo-/metastatic patients in addition to existing classifications. Experts were convinced that GCs might guide treatment decisions in terms of RT-field definition and intensification/deintensification in various disease stages. This work confirms the value of GCs and the promising evidence of GC utility in the setting of RT. Additional studies of GCs as prognostic biomarkers are anticipated and form the basis for future studies addressing predictive capabilities of GCs to optimize RT and systemic therapy. The expert consensus points out future directions for GC research in the management of PCa.

Management of Patients with Recurrent and Metachronous Oligometastatic Prostate Cancer in the Era of PSMA PET

Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scans have higher sensitivity and specificity for detecting lymph nodes or metastatic disease relative to conventional imaging in prostate cancer staging. Since its FDA approval and incorporation into treatment guidelines, the use of PSMA PET has increased in patients undergoing initial staging, those with recurrence after initial definitive treatment, and patients with metastatic disease. Although the early detection of metastatic lesions is changing disease management, it is unclear whether this impact on management translates into clinical benefit. This review will summarize evidence pertaining to the change in patient management due to PSMA PET use and will discuss the implications of PSMA PET on treatment decisions in prostate cancer, particularly in the settings of biochemical recurrence and metachronous oligometastatic disease.

Effect of magnetic resonance imaging pre-processing on the performance of model-based prostate tumor probability mapping

Objective. Multi-parametric magnetic resonance imaging (mpMRI) has become an important tool for the detection of prostate cancer in the past two decades. Despite the high sensitivity of MRI for tissue characterization, it often suffers from a lack of specificity. Several well-established pre-processing tools are publicly available for improving image quality and removing both intra- and inter-patient variability in order to increase the diagnostic accuracy of MRI. To date, most of these pre-processing tools have largely been assessed individually. In this study we present a systematic evaluation of a multi-step mpMRI pre-processing pipeline to automate tumor localization within the prostate using a previously trained model.Approach. The study was conducted on 31 treatment-naïve prostate cancer patients with a PI-RADS-v2 compliant mpMRI examination. Multiple methods were compared for each pre-processing step: (1) bias field correction, (2) normalization, and (3) deformable multi-modal registration. Optimal parameter values were estimated for each step on the basis of relevant individual metrics. Tumor localization was then carried out via a model-based approach that takes both mpMRI and prior clinical knowledge features as input. A sequential optimization approach was adopted for determining the optimal parameters and techniques in each step of the pipeline.Main results. The application of bias field correction alone increased the accuracy of tumor localization (area under the curve (AUC) = 0.77;p-value = 0.004) over unprocessed data (AUC = 0.74). Adding normalization to the pre-processing pipeline further improved diagnostic accuracy of the model to an AUC of 0.85 (p-value = 0.000 12). Multi-modal registration of apparent diffusion coefficient images to T2-weighted images improved the alignment of tumor locations in all but one patient, resulting in a slight decrease in accuracy (AUC = 0.84;p-value = 0.30).Significance. Overall, our findings suggest that the combined effect of multiple pre-processing steps with optimal values has the ability to improve the quantitative classification of prostate cancer using mpMRI. Clinical trials: NCT03378856 and NCT03367702.

Focal HDR brachytherapy boost to stereotactic radiotherapy (fBTsRT) for prostate cancer: a phase II randomized controlled trial

BACKGROUND

For patients with a higher burden of localized prostate cancer, radiation dose escalation with brachytherapy boosts have improved cancer control outcomes at the cost of urinary toxicity. We hypothesize that a focal approach to brachytherapy boosts targeting only grossly visualized tumor volumes (GTV) combined with stereotactic radiotherapy will improve quality of life (QoL) outcomes without compromising cancer control.

METHODS

150 patients with intermediate or high-risk prostate cancer will be enrolled and randomized 1:1 in a cohort multiple randomized clinical trial phase 2 design. Patients are eligible if planned for standard-of-care (SOC) high dose rate (HDR) brachytherapy boost to radiotherapy (RT) with GTVs encompassing < 50% of the prostate gland. Those randomly selected will be offered the experimental treatment, consisting of focal HDR brachytherapy boost (fBT) of 13-15 Gy in 1 fraction followed by stereotactic radiotherapy (sRT) 36.25-40 Gy in 5 fractions to the prostate (+/- 25 Gy to the elective pelvis) delivered every other day. The primary endpoint is to determine if fBTsRT is superior to SOC by having fewer patients experience a minimally important decline (MID) in urinary function as measured by EPIC-26 at 1 and 2 years. Secondary endpoints include rates of toxicity measured by Common Terminology Criteria for Adverse Events (CTCAE), and failure-free survival outcomes.

DISCUSSION

This study will determine whether a novel approach for the treatment of localized prostate cancer, fBTsRT, improves QoL and merits further evaluation. Trial registration This trial was prospectively registered in ClinicalTrials.gov as NCT04100174 as a companion to registry NCT03378856 on September 24, 2019.

The Clinical Significance of Maximum Tumor Diameter on MRI in Men Undergoing Radical Prostatectomy or Definitive Radiotherapy for Locoregional Prostate Cancer

INTRODUCTION

Maximum tumor diameter (MTD) on pretreatment magnetic resonance imaging (MRI) has the potential to further risk stratify for men with prostate cancer (PCa) prior to definitive local therapy. We aim to evaluate the prognostic impact of radiographic maximum tumor diameter (MTD) in men with localized prostate cancer.

PATIENTS AND METHODS

From a single-center retrospective cohort of men receiving definitive treatment for PCa (radical prostatectomy [RP] or radiotherapy [RT]) with available pretreatment MRI, we conducted univariable and multivariable Cox proportional-hazards models for progression using clinical variables including age, NCCN risk group, radiographic extracapsular extension (ECE), radiographic seminal vesical invasion (SVI), and MTD. RP and RT cohorts were analyzed separately. Covariates were used in a classification and regression tree (CART) analysis and progression-free survival was estimated with the Kaplan-Meier method and groups were compared using log-rank tests.

RESULTS

The cohort included 631 patients (n = 428 RP, n = 203 RT). CART analysis identified 4 prognostic groups for patients treated with RP and 2 prognostic groups in those treated with RT. In the RP cohort, NCCN low/intermediate risk group patients with MTD>=15 mm had significantly worse PFS than those with MTD <= 14 mm, and NCCN high-risk patients with radiographic ECE had significantly worse PFS than those without ECE. In the RT cohort, PFS was significantly worse in the cohort with MTD >= 23 mm than those <= 22 mm.

CONCLUSION

Radiographic MTD may be a useful prognostic factor for patients with locoregional prostate cancer. This is the first study to illustrate that the importance of pretreatment tumor size may vary based on treatment modality.

Magnetic Resonance-Guided Adaptive Radiation therapy for Prostate Cancer: The First Results from the MOMENTUM study-An International Registry for the Evidence-Based Introduction of Magnetic Resonance-Guided Adaptive Radiation Therapy

PURPOSE

Magnetic resonance (MR)-guided radiation therapy (MRgRT) is a new technique for treatment of localized prostate cancer (PCa). We report the 12-month outcomes for the first PCa patients treated within an international consortium (the MOMENTUM study) on a 1.5T MR-Linac system with ultrahypofractionated radiation therapy.

METHODS AND MATERIALS

Patients treated with 5 × 7.25 Gy were identified. Prostate specific antigen-level, physician-reported toxicity (Common Terminology Criteria for Adverse Events [CTCAE]), and patient-reported outcomes (Quality of Life Questionnaire PR25 and Quality of Life Questionnaire C30 questionnaires) were recorded at baseline and at 3, 6, and 12 months of follow-up (FU). Pairwise comparative statistics were conducted to compare outcomes between baseline and FU.

RESULTS

The study included 425 patients with localized PCa (11.4% low, 82.0% intermediate, and 6.6% high-risk), and 365, 313, and 186 patients reached 3-, 6-, and 12-months FU, respectively. Median prostate specific antigen level declined significantly to 1.2 ng/mL and 0.1 ng/mL at 12 months FU for the nonandrogen deprivation therapy (ADT) and ADT group, respectively. The peak of genitourinary and gastrointestinal CTCAE toxicity was reported at 3 months FU, with 18.7% and 1.7% grade ≥2, respectively. The QLQ-PR25 questionnaire outcomes showed significant deterioration in urinary domain score at all FU moments, from 8.3 (interquartile range [IQR], 4.1-16.6) at baseline to 12.4 (IQR, 8.3-24.8; P = .005) at 3 months, 12.4 (IQR, 8.3-20.8; P = .018;) at 6 months, and 12.4 (IQR, 8.3-20.8; P = .001) at 12 months. For the non-ADT group, physician- and patient-reported erectile function worsened significantly between baseline and 12 months FU.

CONCLUSIONS

Ultrahypofractionated MR-guided radiation therapy for localized PCa using a 1.5T MR-Linac is effective and safe. The peak of CTCAE genitourinary and gastrointestinal toxicity was reported at 3 months FU. Furthermore, for patients without ADT, a significant increase in CTCAE erectile dysfunction was reported at 12 months FU. These data are useful for educating patients on expected outcomes and informing study design of future comparative-effectiveness studies.

Functional imaging-guided carbon ion irradiation with simultaneous integrated boost for localized prostate cancer: study protocol for a phase II randomized controlled clinical trial

Background

Due to the physical dose distribution characteristic of “Bragg peak” and the biological effect as a kind of high linear energy transfer ray, heavy ion therapy has advantages over conventional photon therapy in both efficacy and safety. Based on the evidence that prostate cancer lesions before treatment are the most common sites of tumor residual or recurrence after treatment, simultaneous integrated boost radiation therapy for prostate cancer has been proven to have the advantage of improving efficacy without increasing toxicities.

Methods

This study is a prospective phase II randomized controlled clinical trial evaluating the efficacy and safety of functional imaging-guided carbon ion irradiation with simultaneous integrated boost for localized prostate cancer. One hundred and forty patients with localized prostate cancer will be randomized into carbon ion radiotherapy group and simultaneous integrated boost carbon ion radiotherapy group at a 1:1 ratio. The primary endpoint is to compare the incidence of treatment-related grade 2 and higher acute toxicities between the two groups according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 4.03. Secondary endpoints are late toxicities, biochemical relapse-free survival, overall survival, progression-free survival, and quality of life.

Discussion

This study adopts functional imaging-guided simultaneous integrated boost of carbon ion radiotherapy for localized prostate cancer, aiming to evaluate the differences in the severity and incidence of acute toxicities in patients with localized prostate cancer treated with carbon ion radiotherapy and simultaneous integrated boost carbon ion radiotherapy, in order to optimize the carbon ion treatment strategy for localized prostate cancer.

Trial registration

ClinicalTrials.gov NCT05010343. Retrospectively registered on 18 August 2021

The Added Value of [18F]Choline PET/CT in Low-Risk Prostate Cancer Staging: A Case Report

In the management of prostate cancer (PCa), correct staging is crucial in order to assess the right therapeutic approach. [18F]Choline PET/CT has been shown to provide more accurate staging information than conventional imaging approaches. The aim of this paper is to provide a real practice demonstration of the impact of [18F]Choline PET/CT on low-risk prostate cancer staging and clinical management. We report a 64-year-old man with biochemical PCa recurrence diagnosis after transurethral resection of the prostate. The patient, after the detection of an increased level of PSA, underwent multi-parametric prostate magnetic resonance imaging (mpMRI) that did not show evidence of disease. The patient was admitted to perform [18F]Choline PET/CT that showed a macroscopic prostate recurrence. Patient underwent photon external beam radiation therapy (EBRT) treatment, and [18F]Choline PET/CT was also used to define treatment volumes. At 3- and 6-month clinical follow-up evaluations, no late toxicity was detected and a significant reduction in PSA value was shown. Therefore, our case highlights the potential usefulness of [18F]Choline PET/CT for the staging of low-risk prostate cancer and its impact on the management and quality of life of such patients. The presented case should urge the scientific community to enhance larger and multicentric studies, assessing more extensively the potential impact of [18F]Choline PET/CT in this clinical scenario.

Integration between Novel Imaging Technologies and Modern Radiotherapy Techniques: How the Eye Drove the Chisel

INTRODUCTION

Targeted dose-escalation and reduction of dose to adjacent organs at risk have been the main goal of radiotherapy in the last decade. Prostate cancer benefited the most from this process. In recent years, the development of Intensity Modulated Radiation Therapy (IMRT) and Stereotactic Body Radiotherapy (SBRT) radically changed clinical practice, also thanks to the availability of modern imaging techniques. The aim of this paper is to explore the relationship between diagnostic imaging and prostate cancer radiotherapy techniques.

MATERIALS AND METHODS

Aiming to provide an overview of the integration between modern imaging and radiotherapy techniques, we performed a non-systematic search of papers exploring the predictive value of imaging before treatment, the role of radiomics in predicting treatment outcomes, implementation of novel imaging in RT planning and influence of imaging integration on use of RT in current clinical practice. Three independent authors (GF, IM and ID) performed an independent review focusing on these issues. Key references were derived from a PubMed query. Hand searching and clinicaltrials.gov were also used, and grey literature was searched for further papers of interest. The final choice of papers included was discussed between all co-authors.

RESULTS

This paper contains a narrative report and a critical discussion of the role of new modern techniques in predicting outcomes before treatment, in radiotherapy planning and in the integration with systemic therapy in the management of prostate cancer. Also, the role of radiomics in a tailored treatment approach is explored.

CONCLUSIONS

Integration between diagnostic imaging and radiotherapy is of great importance for the modern treatment of prostate cancer. Future clinical trials should be aimed at exploring the real clinical benefit of complex workflows in clinical practice.

Development of binational radiation therapy quality indicator reports for prostate cancer treatment using registry data

INTRODUCTION

Quality indicators (QIs) are metrics which seek to allow comparison of clinicians' and institutes' practice to best evidence-based practice. The Australia and New Zealand Prostate Cancer Outcomes Registry (PCOR-ANZ) is a bi-national clinical quality registry with coverage estimated to be over 60% of the men newly diagnosed with prostate cancer. We outline the production and ambition of institute-level QI reports to benchmark performance for radiation therapy in the treatment of prostate cancer.

METHODS

An expert clinician panel was assembled to create a list of candidate QIs based on a comprehensive literature review, and on modified Delphi-method and expert-consensus voting. A separate implementation group-including, clinicians, epidemiologists, data managers and data scientists-employed an evidence- and consensus- based approach to generate an effective QI report designed for automated production and regular distribution to participating institutes. Feedback from the recipient clinicians was sought to enable refinement of these reports.

RESULTS

Seven QIs, including three related to post-treatment symptoms, were deemed feasible to analyse with the currently available data. Utilising an existing report template employed for benchmarking of surgical indicators, a novel radiation therapy report was generated using registry data in a secure analytical environment. The first, beta version of these reports have been produced and confidentially distributed. It is planned to automatically generate these reports biannually and iteratively refine them based on the clinician input.

CONCLUSION

QI reports for the treatment of prostate cancer by radiation oncologists have been produced using data from Australia and New Zealand patients. These are being disseminated to institutes on a six-monthly basis allowing comparisons to de-identified peers. The reports aim to facilitate improving patient outcomes, deepen engagement with the radiation oncology community and increase the breadth of PCOR-ANZ coverage. Additional QIs will be included in future iterations of these reports as data matures.

Dose-Escalated Salvage Radiotherapy for Macroscopic Local Recurrence of Prostate Cancer in the Prostate-Specific Membrane Antigen Positron Emission Tomography Era

Simple Summary

Prostate cancer often relapses after initial radical prostatectomy, and salvage radiotherapy offers a second chance of cure for relapsed patients. Modern imaging techniques, especially prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT), enable radiation oncologists to target radiotherapy at the involved sites of disease. In a group of patients, PSMA PET/CT imaging can detect a macroscopic local recurrence with or without locoregional lymph node metastasis. In these cases, an escalation of the radiotherapy dose is often considered for controlling the visible tumor mass. As the evidence for dose-escalated salvage radiotherapy for macroscopic recurrent prostate cancer after PSMA PET/CT imaging is still limited, we address this topic in the current analysis. We found that the outcome of patients with dose-escalated salvage radiotherapy for macroscopic prostate cancer recurrence is encouragingly favorable, while the toxicity is very limited.

Abstract

Background: The purpose of this study was to access the oncological outcome of prostate-specific membrane antigen positron emission tomography (PSMA PET/CT)-guided salvage radiotherapy (SRT) for localized macroscopic prostate cancer recurrence. Methods: Between February 2010 and June 2021, 367 patients received SRT after radical prostatectomy. Out of the 367 screened patients, 111 patients were staged by PSMA PET/CT before SRT. A total of 59 out of these 111 (53.2%) patients were treated for PSMA PET-positive macroscopic prostatic fossa recurrence. Dose-escalated SRT was applied with a simultaneous integrated boost at a median prescribed dose of 69.3 Gy (IQR 69.3–72.6 Gy). The oncological outcome was investigated using Kaplan-Meier and Cox regression analyses. The genitourinary (GU)/gastrointestinal (GI) toxicity evaluation utilized Common Toxicity Criteria for Adverse Events (version 5.0). Results: The median follow-up was 38.2 months. The three-year biochemical progression-free survival rate was 89.1% (95% CI: 81.1–97.8%) and the three-year metastasis-free survival rate reached 96.2% (95% CI: 91.2–100.0%). The cumulative three-year late grade 3 GU toxicity rate was 3.4%. No late grade 3 GI toxicity occurred. Conclusions: Dose-escalated PSMA PET/CT-guided salvage radiotherapy for macroscopic prostatic fossa recurrence resulted in favorable survival and toxicity rates.

Ex vivo γH2AX assay for tumor radiosensitivity in primary prostate cancer patients and correlation with clinical parameters

Backround

Accurate surrogate parameters for radio resistance are warranted for individualized radiotherapy (RT) concepts in prostate cancer (PCa). The purpose of this study was to assess intertumoral heterogeneity in terms of radio resistance using an ex-vivo γH2AX assay after irradiation of prostate biopsy cores and to investigate its correlation with clinical features of respective patients as well as imaging and genomic features of tumor areas.

Methods

Twenty one patients with histologically-proven PCa and pre-therapeutic multiparametric resonance imaging and prostate-specific membrane antigen positron emission tomography were included in the study. Biopsy cores were collected from 26 PCa foci. Residual γH2AX foci were counted 24 h after ex-vivo irradiation (with 0 and 4 Gy) of biopsy specimen and served as a surrogate for radio resistance. Clinical, genomic (next generation sequencing) and imaging features were collected and their association with the radio resistance was studied.

Results

In total 18 PCa lesions from 16 patients were included in the final analysis. The median γH2AX foci value per PCa lesion was 3.12. According to this, the patients were divided into two groups (radio sensitive vs. radio resistant) with significant differences in foci number (p < 0.0001). The patients in the radio sensitive group had significantly higher prostate specific antigen serum concentration (p = 0.015), tumor areas in the radio sensitive group had higher SUV (standardized uptake values in PSMA PET)-max and -mean values (p = 0.0037, p = 0.028) and lower ADC (apparent diffusion coefficient-mean values, p = 0.049). All later parameters had significant (p < 0.05) correlations in Pearson’s test. One patient in the radio sensitive group displayed a previously not reported loss of function frameshift mutation in the NBN gene (c.654_658delAAAAC) that introduces a premature termination codon and results in a truncated protein.

Conclusion

In this pilot study, significant differences in intertumoral radio resistance were observed and clinical as well as imaging parameters may be applied for their prediction. After further prospective validation in larger patient cohorts these finding may lead to individual RT dose prescription for PCa patients in the future.

Modern paradigms for prostate cancer detection and management

Early detection and management of prostate cancer has evolved over the past decade, with a focus now on harm minimisation and reducing overdiagnosis and overtreatment, given the proven improvements in survival from randomised controlled trials. Multiparametric magnetic resonance imaging (mpMRI) is now an important aspect of the diagnostic pathway in prostate cancer, improving the detection of clinically significant prostate cancer, enabling accurate localisation of appropriate sites to biopsy, and reducing unnecessary biopsies in most patients with normal magnetic resonance imaging scans. Biopsies are now performed transperineally, substantially reducing the risk of post-procedure sepsis. Australian-led research has shown that prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) has superior accuracy in the staging of prostate cancer than conventional imaging (CT and whole-body bone scan). Localised prostate cancer that is low risk (International Society for Urological Pathology [ISUP] grade 1, Gleason score 3 + 3 = 6; and ISUP grade group 2, Gleason score 3 + 4 = 7 with less than 10% pattern 4) can be offered active surveillance, reducing harms from overtreatment. Prostatectomy and definitive radiation remain the gold standard for localised intermediate and high risk disease. However, focal therapy is an emerging experimental treatment modality in Australia in carefully selected patients. The management of advanced prostate cancer treatment has evolved to now include several novel agents both in the metastatic hormone-sensitive and castration-resistant disease settings. Multimodal therapy with androgen deprivation therapy, additional systemic therapy and radiotherapy are often recommended. PSMA-based radioligand therapy has emerged as a treatment option for metastatic castration-resistant prostate cancer and is currently being evaluated in earlier disease states.

[Radiation dose intensification for glioblastoma]

Glioblastoma is the most common brain tumor in adults; its treatment includes surgical excision or biopsy followed by radio-chemotherapy. Even if radiotherapy increases the survival of all patients regardless of their age or their general condition, there are always sources of radioresistance, where relapses occur and therefore treatment fails. Indeed, these foci result in a local relapse, which is observed in 95% of cases in the irradiation fields. We will describe here the current approaches to overcome this radioresistance by dose escalation, without or with guidance by metabolic and functional imaging (dose-painting). We will detail several prospective trials including the French phase III trial, SPECTRO-GLIO, randomizing the use of an integrated boost guided by spectrometric magnetic resonance imaging and similar trials developed across the Atlantic. We will also discuss approaches using different PET markers as well as diffusion or perfusion magnetic resonance imaging.

Intensity-modulated radiotherapy versus stereotactic body radiotherapy for prostate cancer (PACE-B): 2-year toxicity results from an open-label, randomised, phase 3, non-inferiority trial

BACKGROUND

Localised prostate cancer is commonly treated with external beam radiotherapy and moderate hypofractionation is non-inferior to longer schedules. Stereotactic body radiotherapy (SBRT) allows shorter treatment courses without impacting acute toxicity. We report 2-year toxicity findings from PACE-B, a randomised trial of conventionally fractionated or moderately hypofractionated radiotherapy versus SBRT.

METHODS

PACE is an open-label, multicohort, randomised, controlled, phase 3 trial conducted at 35 hospitals in the UK, Ireland, and Canada. In PACE-B, men aged 18 years and older with a WHO performance status 0-2 and low-risk or intermediate-risk histologically-confirmed prostate adenocarcinoma (Gleason 4 + 3 excluded) were randomly allocated (1:1) by computerised central randomisation with permuted blocks (size four and six), stratified by centre and risk group to control radiotherapy (CRT; 78 Gy in 39 fractions over 7·8 weeks or, following protocol amendment on March 24, 2016, 62 Gy in 20 fractions over 4 weeks) or SBRT (36·25 Gy in five fractions over 1-2 weeks). Androgen deprivation was not permitted. Co-primary outcomes for this toxicity analysis were Radiation Therapy Oncology Group (RTOG) grade 2 or worse gastrointestinal and genitourinary toxicity at 24 months after radiotherapy. Analysis was by treatment received and included all patients with at least one fraction of study treatment assessed for late toxicity. Recruitment is complete. Follow-up for oncological outcomes continues. The trial is registered with ClinicalTrials.gov, NCT01584258.

FINDINGS

We enrolled and randomly assigned 874 men between Aug 7, 2012, and Jan 4, 2018 (441 to CRT and 433 to SBRT). In this analysis, 430 patients were analysed in the CRT group and 414 in the SBRT group; a total of 844 (97%) of 874 randomly assigned patients. At 24 months, RTOG grade 2 or worse genitourinary toxicity was seen in eight (2%) of 381 participants assigned to CRT and 13 (3%) of 384 participants assigned to SBRT (absolute difference 1·3% [95% CI -1·3 to 4·0]; p=0·39); RTOG grade 2 or worse gastrointestinal toxicity was seen in 11 (3%) of 382 participants in the CRT group versus six (2%) of 384 participants in the SBRT group (absolute difference -1·3% [95% CI -3·9 to 1·1]; p=0·32). No serious adverse events (defined as RTOG grade 4 or worse) or treatment-related deaths were reported within the analysis timeframe.

INTERPRETATION

In the PACE-B trial, 2-year RTOG toxicity rates were similar for five fraction SBRT and conventional schedules of radiotherapy. Prostate SBRT was found to be safe and associated with low rates of side-effects. Biochemical outcomes are awaited.

FUNDING

Accuray.

Enrichment of "Cribriform" morphologies (intraductal and cribriform adenocarcinoma) and genomic alterations in radiorecurrent prostate cancer

Locally relapsed prostate cancer (PCa) after radiation therapy (RT) is associated with substantial morbidity and mortality. Morphological and molecular consequences that may contribute to RT resistance and local recurrence remain poorly understood. Locally recurrent PCa tissue from 53 patients with clinically localized PCa who failed with primary RT and subsequently underwent salvage radical prostatectomy (RP) was analyzed for tumor focality, clinicopathological, molecular, and genomic characteristics. Targeted next-generation sequencing with full exon coverage of 1,425 cancer-related genes was performed on 10 representative radiorecurrent PCas exhibiting no RT effect with matched adjacent benign prostate tissue. At RP, 37 (70%) of PCas had no RT effect with the following characteristics: grade group (GG) ≥ 3 (70%), unifocal tumor (75%), extraprostatic disease (78%), lymph node metastasis (8%), and "cribriform" morphologies (84%) [cribriform PCa (78%) or intraductal carcinoma (IDC-P) (61%)] at a median percentage of approximately 80% of tumor volume. In the setting of multifocal tumors (25%) at RP, the cribriform morphologies were restricted to index tumors. Of 32 patients with available pre-RT biopsy information, 16 had GG1 PCa, none had cribriform morphologies at baseline but 81% demonstrated cribriform morphologies at RP. Notable alterations detected in the sequenced tumors included: defects in DNA damage response and repair (DDR) genes (70%) (TP53, BRCA2, PALB2, ATR, POLQ), PTEN loss (50%), loss of 8p (80%), and gain of MYC (70%). The median tumor mutational burden was 4.18 mutations/Mb with a range of 2.16 to 31.86. Our findings suggest that most radiorecurrent PCas are enriched in cribriform morphologies with potentially targetable genomic alterations. Understanding this phenotypic and genotypic diversity of radiorecurrent PCa is critically important to facilitate optimal patient management.

Efficacy, toxicity, and quality-of-life outcomes of ultrahypofractionated radiotherapy in patients with localized prostate cancer: A single-arm phase 2 trial from Asia

AIMS

Ultra-hypofractionated radiotherapy (UHF-RT) is widely utilized in men with localized prostate cancer (PCa). There are limited data in Asian cohorts. We report the outcomes of a single-arm, phase II trial of UHF-RT from an Asian center.

METHODS

We recruited men with histologically confirmed, nonmetastatic localized PCa. UHF-RT regimens were 36.25 Gy (Cohort A) and 37.5 Gy (Cohort B) delivered in five fractions every other day over 1.5-2.5 weeks. Primary endpoint was physician-scored late genitourinary (GU) and gastrointestinal (GI) adverse events (AEs). Quality-of-life (QoL) was assessed by Expanded Prostate Cancer Index Composite (EPIC) at baseline, 1- and 2-year post-UHF-RT.

RESULTS

Between March 2014 and August 2019, 105 men were recruited; four were subsequently excluded from analysis. Median age was 68.0 (Interquartile range (IQR): 63.8-73.0) years. 26 (24.8%) and 68 (64.8%) men had NCCN-defined low-and intermediate-risk PCa, respectively. No late ≥G3 GU or GI toxicities were reported in both cohorts. Peak incidence of acute ≥G2 GU AEs at 14 days post-UHF-RT was 23.6% (17/72) and 24.0% (6/25) in Cohorts A and B, respectively; ≥G2 GI AEs were observed in 9.7% (7/72) and 36.0% (9/25), respectively. Late ≥G2 GU and GI AEs occurred in 4.7% and 3.1% of Cohort A patients, and 5.0% in Cohort B at 12 months, with no AEs at 24 months. EPIC scores changed minimally across all domains. At a median follow-up of 44.9 months, we recorded one (1.3%) biochemical relapse by the Phoenix criteria (Cohort A).

CONCLUSION

UHF-RT is well tolerated in Asian men and can be a recommended fractionation schema for localized PCa.

Reliability of gradient-based segmentation for measuring metabolic parameters influenced by uptake time on 18F-PSMA-1007 PET/CT for prostate cancer

Purpose

To determine an optimal setting for functional contouring and quantification of prostate cancer lesions with minimal variation by evaluating metabolic parameters on 18F-PSMA-1007 PET/CT measured by threshold-based and gradient-based methods under the influence of varying uptake time.

Methods and materials

Dual time point PET/CT was chosen to mimic varying uptake time in clinical setting. Positive lesions of patients who presented with newly diagnosed disease or biochemical recurrence after total prostatectomy were reviewed retrospectively. Gradient-based and threshold-based tools at 40%, 50% and 60% of lesion SUVmax (MIM 6.9) were used to create contours on PET. Contouring was considered completed if the target lesion, with its hottest voxel, was delineated from background tissues and nearby lesions under criteria specific to their operations. The changes in functional tumour volume (FTV) and metabolic tumour burden (MTB, defined as the product of SUVmean and FTV) were analysed. Lesion uptake patterns (increase/decrease/stable) were determined by the percentage change in tumour SUVmax at ±10% limit.

Results

A total of 275 lesions (135 intra-prostatic lesions, 65 lymph nodes, 45 bone lesions and 30 soft tissue lesions in pelvic region) in 68 patients were included. Mean uptake time of early and delayed imaging were 94 and 144 minutes respectively. Threshold-based method using 40% to 60% delineated only 85 (31%), 110 (40%) and 137 (50%) of lesions which all were contoured by gradient-based method. Although the overall percentage change using threshold at 50% was the smallest among other threshold levels in FTV measurement, it was still larger than gradient-based method (median: 50%=-7.6% vs gradient=0%). The overall percentage increase in MTB of gradient-based method (median: 6.3%) was compatible with the increase in tumour SUVmax. Only a small proportion of intra-prostatic lesions (&lt;2%), LN (&lt;4%), bone lesions (0%) and soft tissue lesions (&lt;4%) demonstrated decrease uptake patterns.

Conclusions

With a high completion rate, gradient-based method is reliable for prostate cancer lesion contouring on 18F-PSMA-1007 PET/CT. Under the influence of varying uptake time, it has smaller variation than threshold-based method for measuring volumetric parameters. Therefore, gradient-based method is recommended for tumour delineation and quantification on 18F-PSMA-1007 PET/CT.

Immunomodulatory effects of carbon ion radiotherapy in patients with localized prostate cancer

PURPOSE

Radiotherapy is one of the main local treatment modalities for prostate cancer, while immunosuppressive effect induced by radiotherapy is an important factor of radiation resistance and treatment failure. Carbon ion radiotherapy (CIRT) is a novel radiotherapy technique and the immunomodulatory effect of CIRT provides the possibility of overcoming radioresistance and improving efficacy. The aim of this study was to assess the immune response evoked by CIRT in localized prostate cancer patients.

METHODS

Thirty-two patients were treated by CIRT combined with or without hormone therapy and peripheral blood samples were collected before and after CIRT. Investigation of peripheral immune cell frequency, proliferation, and cytokine expression was conducted by flow cytometry, real-time quantitative PCR and ELISA.

RESULTS

There were no significant differences in the frequencies of CD3 + , CD4 + , CD8 + T cells and NK cells after CIRT. CD4/CD8 ratio increased whereas B cells decreased. All lymphocyte subsets except regulatory T cells (Tregs) displayed increased proliferation and T cells exhibited increased functionality after CIRT, characterized by modestly increased cytokine secretion of TNF. Moreover, higher frequencies of Tregs were shown. Neither monocytic myeloid-derived suppressor cells (MDSCs) nor early MDSCs changed after CIRT. TGF-β1 gene expression decreased while IL-6 showed a non-significant trend towards a decrease. Both IL-10 gene expression and plasma TGF-β1 level were unchanged.

CONCLUSION

CIRT demonstrates the potential to elicit immune activation in localized prostate cancer patients, based on sparing lymphocytes, increased lymphocyte proliferation, enhanced T-cell functionality, together with limited induction of immunosuppressive cells and reduced expression of immunosuppressive cytokines.

Cost effectiveness of treatment strategies for high risk prostate cancer

BACKGROUND

Patients with high-risk prostate cancer (HRPC) have multiple accepted treatment options. Because there is no overall survival benefit of one option over another, appropriate treatment must consider patient life expectancy, quality of life, and cost.

METHODS

The authors compared quality-adjusted life years (QALYs) and cost effectiveness among treatment options for HRPC using a Markov model with three treatment arms: (1) external-beam radiotherapy (EBRT) delivered with 20 fractions, (2) EBRT with 23 fractions followed by low-dose-rate (LDR) brachytherapy boost, or (3) radical prostatectomy alone. An exploratory analysis considered a simultaneous integrated boost according to the FLAME trial (ClinicalTrials.gov identifier NCT01168479).

RESULTS

Treatment strategies were compared using the incremental cost-effectiveness ratio (ICER). EBRT with LDR brachytherapy boost was a cost-effective strategy (ICER, $20,929 per QALY gained). These results were most sensitive to variations in the biochemical failure rate. However, the results still demonstrated cost effectiveness for the brachytherapy boost paradigm, regardless of any tested parameter ranges. Probabilistic sensitivity analysis demonstrated that EBRT with LDR brachytherapy was favored in 52% of 100,000 Monte Carlo iterations. In an exploratory analysis, EBRT with a simultaneous integrated boost was also a cost-effective strategy, resulting in an ICER of $62,607 per QALY gained; however, it was not cost effective compared with EBRT plus LDR brachytherapy boost.

CONCLUSIONS

EBRT with LDR brachytherapy boost may be a cost-effective treatment strategy compared with EBRT alone and radical prostatectomy for HRPC, demonstrating high-value care. The current analysis suggests that a reduction in biochemical failure alone can result in cost-effective care, despite no change in overall survival.

Adaptive magnetic resonance image guided radiation for intact localized prostate cancer how to optimally test a rapidly emerging technology

Introduction

Prostate cancer is a common malignancy for which radiation therapy (RT) provides an excellent management option with high rates of control and low toxicity. Historically RT has been given with CT based image guidance. Recently, magnetic resonance (MR) imaging capabilities have been successfully integrated with RT delivery platforms, presenting an appealing, yet complex, expensive, and time-consuming method of adapting and guiding RT. The precise benefits of MR guidance for localized prostate cancer are unclear. We sought to summarize optimal strategies to test the benefits of MR guidance specifically in localized prostate cancer.

Methods

A group of radiation oncologists, physicists, and statisticians were identified to collectively address this topic. Participants had a history of treating prostate cancer patients with the two commercially available MRI-guided RT devices. Participants also had a clinical focus on randomized trials in localized prostate cancer. The goal was to review both ongoing trials and present a conceptual focus on MRI-guided RT specifically in the definitive treatment of prostate cancer, along with developing and proposing novel trials for future consideration. Trial hypotheses, endpoints, and areas for improvement in localized prostate cancer that specifically leverage MR guided technology are presented.

Results

Multiple prospective trials were found that explored the potential of adaptive MRI-guided radiotherapy in the definitive treatment of prostate cancer. Different primary areas of improvement that MR guidance may offer in prostate cancer were summarized. Eight clinical trial design strategies are presented that summarize options for clinical trials testing the potential benefits of MRI-guided RT.

Conclusions

The number and scope of trials evaluating MRI-guided RT for localized prostate cancer is limited. Yet multiple promising opportunities to test this technology and potentially improve outcomes for men with prostate cancer undergoing definitive RT exist. Attention, in the form of multi-institutional randomized trials, is needed.

Dose-escalation in prostate cancer: Results of randomized trials

In 1998, an editorial from the International Journal of Radiation Oncology - Biology - Physics (IJROBP) on the occasion of the publication of Phase I by Zelefsky et al. on 3D radiotherapy dose escalation asked the question: "will more prove better?". More than 20 years later, several prospective studies have supported the authors' conclusions, making dose escalation a new standard in prostate cancer. The data from prospective randomized studies were ultimately disappointing in that they failed to show an overall survival benefit from dose escalation. However, there is a clear and consistent benefit in biochemical recurrence-free survival, which must be weighed on an individual patient basis against the potential additional toxicity of dose escalation. Techniques and concepts have become more and more precise, such as intensity modulated irradiation, simultaneous integrated boost, hypofractionated dose-escalation, pelvic irradiation with involved node boost or focal dose-escalation on gross recurrence after prostatectomy. The objective here was to summarize the prospective data on dose escalation in prostate cancer and in particular on recent advances in the field. In 2022, can we finally say that more has proven better?