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ABSTRACT Introduction Methods Results Conclusion This study aimed to prospectively investigate magnetic resonance (MR)‐guided radiotherapy (MRgRT) for post‐prostatectomy prostate cancer and report preliminary clinical outcomes.All included patients underwent salvage or adjuvant adaptive MRgRT on a 1.5T MR integrated linear accelerator (MR‐LINAC). Gastrointestinal and genitourinary toxicities were assessed. The primary endpoint was the progression‐free survival (PFS) rate estimated by Kaplan‐Meier (KM) survival analysis. A progression event was defined as the first occurrence of biochemical failure, radiological progression, or death. Secondary endpoints were biochemical failure‐free survival (bFFS) rate, radiological PFS (rPFS) rate, and ≥G2 adverse events.Thirty post‐prostatectomy patients were enrolled and followed (median follow‐up: 32.0 months; 3.0–48.1 months). Three patients had biochemical failure during follow‐up. One patient developed pelvic node metastases. All patients were alive. The estimated PFS rates were 96.4% (95% confidence interval [95%CI]: 89.8%–100.0%) at 2 years and 78.8% (95%CI: 61.3%–100%) at 3 years. The estimated bFFS rates were 96.4% (95%CI: 89.8%–100%) /86.6%(95%CI: 73.4%–100%) at 2/3 years, respectively. The corresponding rPFS rates were 100% at 2 years and 92.3% (95%CI: 78.9%–100%) at 3 years, respectively. There was only one acute G2 GI adverse event (1/30, 3.33%) of abdominal pain occurred. Two late G2 events (one rectal bleeding and one urinary frequency) were scored (2/30, 6.67%). No ≥G3 events were observed.Our findings suggest the feasibility, excellent patient tolerance, and encouraging efficacy of post‐prostatectomy MRgRT, extending our knowledge of the clinical outcomes of MRgRT and serving as a benchmark for future investigation. [ABSTRACT FROM AUTHOR]

Aim: The aim of the third Asia‐Pacific Advanced Prostate Cancer Consensus Conference (APAC APCCC 2023) was to discuss the application in the Asia‐Pacific (APAC) region of consensus statements from the 4th Advanced Prostate Cancer Consensus Conference (APCCC 2022). Methods: The one‐day meeting in July 2023 brought together 27 experts from 14 APAC countries. The meeting covered five topics: (1) Intermediate‐ and high‐risk and locally advanced prostate cancer; (2) Management of newly diagnosed metastatic hormone‐sensitive prostate cancer; (3) Management of non‐metastatic castration‐resistant prostate cancer; (4) Homologous recombination repair mutation testing; (5) Management of metastatic castration‐resistant prostate cancer. Pre‐ and post‐symposium polling gathered APAC‐specific responses to APCCC consensus questions and insights on current practices and challenges in the APAC region. Results: APAC APCCC highlights APAC‐specific considerations in an evolving landscape of diagnostic technologies and treatment innovations for advanced prostate cancer. While new technologies are available in the region, cost and reimbursement continue to influence practice significantly. Individual patient considerations, including the impact of chemophobia on Asian patients, also influence decision‐making. Conclusion: The use of next‐generation imaging, genetic testing, and new treatment combinations is increasing the complexity and duration of prostate cancer management. Familiarity with new diagnostic and treatment options is growing in the APAC region. Insights highlight the continued importance of a multidisciplinary approach that includes nuclear medicine, genetic counseling, and quality‐of‐life expertise. The APAC APCCC meeting provides an important opportunity to share practice and identify APAC‐specific issues and considerations in areas of low evidence where clinical experience is growing. [ABSTRACT FROM AUTHOR]

For patients with metastatic hormone-sensitive prostate cancer, no head-to-head randomized trial has compared abiraterone and docetaxel when added to androgen deprivation therapy. This real-world efficacy and toxicity analysis of 574 Asian patients demonstrated significantly longer progression-free survival and similar overall survival in those who received the abiraterone over docetaxel combination. Prediction models suggested several prognostic markers, including a ≥ 90% decline in prostate-specific antigen (PSA) level at 3 months, which may be useful for treatment intensification. Introduction: Abiraterone acetate (ABI) or docetaxel (DOC), in addition to androgen-deprivation therapy (ADT), are current treatment options for metastatic hormone-sensitive prostate cancer (mHSPC). No randomized head-to-head trial has compared these 2 mHSPC treatments, and real-world data regarding their outcomes in Asian patients are lacking. Patients and Methods: The medical records of mHSPC patients who began upfront ABI or DOC treatment in addition to ADT at seven public oncology centers in Hong Kong between 2015 and 2021 were reviewed. The primary endpoint was progression-free sur vival (PFS). Secondar y endpoints included overall sur vival (OS), prostate-specific antigen (PSA) response, and toxicities. Kaplan-Meier and multivariate Cox regression analyses were performed. Results: A total of 574 patients were included, of whom 419 received DOC and 155 received ABI. The median follow-up duration was 22.4 (DOC group: 23.8; ABI group: 17.3) months. The ABI group demonstrated significantly better PFS than the DOC group (not reached vs. 15.1 months: hazard ratio = 0.37; 95% confidence interval = 0.28-0.50; P < .001). No significant OS difference was observed (P = .58). Failure to achieve a = 90% decline in PSA level at 3 months and failure to achieve an undetectable PSA nadir were each associated with unfavorable PFS and OS. Patients who received DOC had a higher rate of febrile neutropenia, whereas those who received ABI had higher rates of grade = 3 hypokalemia and elevated alanine transaminase. Treatment discontinuation due to toxicities was more common in the DOC (3.6%) than the ABI (0.6%) group. Conclusion: In Asian mHSPC patients, upfront ABI + ADT was associated with better PFS than 1 DOC + ADT, with no significant OS difference. PSA kinetics may help stratify the prognosis for treatment intensification. Toxicity profiles were different, with a higher rate of toxicity-related treatment discontinuation in the DOC group. [ABSTRACT FROM AUTHOR]

Radiomics has the potential to aid prostate cancer (PC) diagnoses and prediction by analyzing and modeling quantitative features extracted from clinical imaging. However, its reliability has been a concern, possibly due to its high-dimensional nature. This study aims to quantitatively investigate the impact of randomly generated irrelevant features on MRI radiomics feature selection, modeling, and performance by progressively adding randomly generated features. Two multiparametric-MRI radiomics PC datasets were used (dataset 1 (n = 260), dataset 2 (n = 100)). The endpoint was to differentiate pathology-confirmed clinically significant (Gleason score (GS) ≥ 7) from insignificant (GS < 7) PC. Random features were generated at 12 levels with a 10% increment from 0% to 100% and an additional 5%. Three feature selection algorithms and two classifiers were used to build the models. The area under the curve and accuracy were used to evaluate the model's performance. Feature importance was calculated to assess features' contributions to the models. The metrics of each model were compared using an ANOVA test with a Bonferroni correction. A slight tendency to select more random features with the increasing number of random features introduced to the datasets was observed. However, the performance of the radiomics-built models was not significantly affected, which was partially due to the higher contribution of radiomics features toward the models compared to the random features. These reliability effects also vary among datasets. In conclusion, while the inclusion of additional random features may still slightly impact the performance of the feature selection, it may not have a substantial impact on the MRI radiomics model performance. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the potential value of MRI radiomics obtained from a 1.5 T MRI‐guided linear accelerator (MR‐LINAC) for D'Amico high‐risk prostate cancer (PC) classification in MR‐guided radiotherapy (MRgRT). Methods: One hundred seventy‐six consecutive PC patients underwent 1.5 T MRgRT treatment were retrospectively enrolled. Each patient received one or two pretreatment T2‐weighted MRI scans on a 1.5 T MR‐LINAC. The endpoint was to differentiate high‐risk from low/intermediate‐risk PC based on D'Amico criteria using MRI‐radiomics. Totally 1023 features were extracted from clinical target volume (CTV) and planning target volume (PTV). Intraclass correlation coefficient of scan–rescan repeatability, feature correlation, and recursive feature elimination were used for feature dimension reduction. Least absolute shrinkage and selection operator regression was employed for model construction. Receiver operating characteristic area under the curve (AUC) analysis was used for model performance assessment in both training and testing data. Results: One hundred and eleven patients fulfilled all criteria were finally included: 76 for training and 35 for testing. The constructed MRI‐radiomics models extracted from CTV and PTV achieved the AUC of 0.812 and 0.867 in the training data, without significant difference (P = 0.083). The model performances remained in the testing. The sensitivity, specificity, and accuracy were 85.71%, 64.29%, and 77.14% for the PTV‐based model; and 71.43%, 71.43%, and 71.43% for the CTV‐based model. The corresponding AUCs were 0.718 and 0.750 (P = 0.091) for CTV‐ and PTV‐based models. Conclusion: MRI‐radiomics obtained from a 1.5 T MR‐LINAC showed promising results in D'Amico high‐risk PC stratification, potentially helpful for the future PC MRgRT. Prospective studies with larger sample sizes and external validation are warranted for further verification. [ABSTRACT FROM AUTHOR]

Purpose: Determination of reliable change of radiomics feature over time is essential and vital in delta-radiomics, but has not yet been rigorously examined. This study attempts to propose a methodological approach using reliable change index (RCI), a statistical metric to determine the reliability of quantitative biomarker changes by accounting for the baseline measurement standard error, in delta-radiomics. The use of RCI was demonstrated with the MRI data acquired from a group of prostate cancer (PCa) patients treated by 1.5 T MRI-guided radiotherapy (MRgRT). Methods: Fifty consecutive PCa patients who underwent five-fractionated MRgRT were retrospectively included, and 1023 radiomics features were extracted from the clinical target volume (CTV) and planning target volume (PTV). The two MRI datasets acquired at the first fraction (MRI11 and MRI21) were used to calculate the baseline feature reliability against image acquisition using intraclass correlation coefficient (ICC). The RCI was constructed based on the baseline feature measurement standard deviation, ICC, and feature value differences at two time points between the fifth (MRI51) and the first fraction MRI (MRI11). The reliable change of features was determined in each patient only if the calculated RCI was over 1.96 or smaller than -1.96. The feature changes between MRI51 and MRI11 were correlated to two patient-reported quality-of -life clinical endpoints of urinary domain summary score (UDSS) and bowel domain summary score (BDSS) in 35 patients using the Spearman correlation test. Only the significant correlations between a feature that was reliably changed in =7 patients (20%) by RCI and an endpoint were considered as true significant correlations. Results: The 352 (34.4%) and 386 (37.7%) features among all 1023 features were determined by RCI to be reliably changed in more than five (10%) patients in the CTV and PTV, respectively. Nineteen features were found reliably changed in the CTV and 31 features in the PTV, respectively, in 10 (20%) or more patients. These features were not necessarily associated with significantly different longitudinal feature values (group p-value < 0.05). Most reliably changed features in more than 10 patients had excellent or good baseline test-retest reliability ICC, while none showed poor reliability. The RCI method ruled out the features to be reliably changed when substantial feature measurement bias was presented. After applying the RCI criterion, only four and five true significant correlations were confirmed with UDSS and BDSS in the CTV, respectively, with low true significance correlation rates of 10.8% (4/37) and 17.9% (5/28). No true significant correlations were found in the PTV. Conclusions: The RCI method was proposed for delta-radiomics and demonstrated using PCa MRgRT data. The RCI has advantages over some other statistical metrics commonly used in the previous delta-radiomics studies, and is useful to reliably identify the longitudinal radiomics feature change on an individual basis. This proposed RCI method should be helpful for the development of essential feature selection methodology in delta-radiomics. [ABSTRACT FROM AUTHOR]

Aim: The second Asia‐Pacific Advanced Prostate Cancer Consensus Conference (APAC APCCC 2020) gathered insights into the real‐world application in the Asia‐Pacific (APAC) region of consensus statements from the 3rd Advanced Prostate Cancer Consensus Conference (APCCC 2019). Methods: The 4‐h our virtual meeting in October 2020 brought together 26 experts from 14 APAC countries to discuss APCCC 2019 recommendations. Presentations were prerecorded and viewed prior to the meeting. A postmeeting survey gathered views on current practice. Results: The meeting and survey highlighted several developments since APAC APCCC 2018. Increased access and use in the region of PSMA PET/CT imaging is providing additional diagnostic and staging information for advanced prostate cancer and influencing local and systemic therapy choices. Awareness of oligometastatic disease, although not clearly defined, is increasing. Novel androgen receptor pathway antagonists are expanding treatment options. Cost and access to contemporary treatments and technologies continue to be a significant factor influencing therapeutic decisions in the region. With treatment options increasing, multidisciplinary treatment planning, shared decision making, and informed choice remain critical. A discussion on the COVID‐19 pandemic highlighted challenges for diagnosis, treatment, and clinical trials and new service delivery models that will continue beyond the pandemic. Conclusion: APAC‐specific prostate cancer research and data are important to ensure that treatment guidelines and recommendations reflect local populations and resources. Facilitated approaches to collaboration across the region such as that achieved through APAC APCCC meetings continue to be a valuable mechanism to ensure the relevance of consensus guidelines within the region. [ABSTRACT FROM AUTHOR]

Background: Stereotactic body radiotherapy (SBRT) has potential radiobiologic and economic advantages over conventional fractionated radiotherapy (CFRT) in localized prostate cancer (PC). This study aimed to compare the effects of these two distinct fractionations on patient-reported quality of life (PRQOL) and tolerability. Methods: In this prospective phase II study, patients with low- and intermediate-risk localized PC were randomly assigned in a 1:1 ratio to the SBRT (36.25 Gy/5 fractions/2 weeks) or CFRT (76 Gy/38 fractions/7.5 weeks) treatment groups. The primary endpoint of variation in PRQOL at 1 year was assessed by changes in the Expanded Prostate Cancer Index Composite (EPIC) questionnaire scores and analysed by z-tests and t-tests. Results: Sixty-four eligible Chinese men were treated (SBRT, n = 31; CFRT, n = 33) with a median follow-up of 2.3 years. At 1 year, 40.0%/46.9% of SBRT/CFRT patients had a >5-point decrease in bowel score (p = 0.08/0.28), respectively, and 53.3%/46.9% had a >2-point decrease in urinary score (p = 0.21/0.07). There were no significant differences in EPIC score changes between the arms at 3, 6, 9 and 12 months, but SBRT was associated with significantly fewer grade ≥ 1 acute and 1-year late gastrointestinal toxicities (acute: 35% vs. 87%, p < 0.0001; 1-year late: 64% vs. 84%, p = 0.03), and grade ≥ 2 acute genitourinary toxicities (3% vs. 24%, p = 0.04) compared with CFRT. Conclusion: SBRT offered similar PRQOL and less toxicity compared with CFRT in Chinese men with localized PC. [ABSTRACT FROM AUTHOR]