RNA-seq profiling of a radiation resistant and radiation sensitive prostate cancer cell line highlights opposing regulation of DNA repair and targets for radiosensitization

Background: Radiotherapy is a chosen treatment option for prostate cancer patients and while some tumours respond well, up to 50% of patients may experience tumour recurrence. Identification of functionally relevant predictive biomarkers for radioresponse in prostate cancer would enable radioresistant patients to be directed to more appropriate treatment options, avoiding the side-effects of radiotherapy. Methods: Using an in vitro model to screen for novel biomarkers of radioresistance, transcriptome analysis of a radioresistant (PC-3) and radiosensitive (LNCaP) prostate cancer cell line was performed. Following pathway analysis candidate genes were validated using qRT-PCR. The DNA repair pathway in radioresistant PC-3 cells was then targeted for radiation sensitization using the PARP inhibitor, niacinimide. Results: Opposing regulation of a DNA repair and replication pathway was observed between PC-3 and LNCaP cells from RNA-seq analysis. Candidate genes BRCA1, RAD51, FANCG, MCM7, CDC6 and ORC1 were identified as being significantly differentially regulated post-irradiation. qRT-PCR validation confirmed BRCA1, RAD51 and FANCG as being significantly differentially regulated at 24 hours post radiotherapy (p-value =0.003, 0.045 and 0.003 respectively). While the radiosensitive LNCaP cells down-regulated BRCA1, FANCG and RAD51, the radioresistant PC-3 cell line up-regulated these candidates to promote cell survival post-radiotherapy and a similar trend was observed for MCM7, CDC6 and ORC1. Inhibition of DNA repair using niacinamide sensitised the radioresistant cells to irradiation, reducing cell survival at 2 Gy from 66% to 44.3% (p-value =0.02). Conclusions: These findings suggest that the DNA repair candidates identified via RNA-seq hold potential as both targets for radiation sensitization and predictive biomarkers in prostate cancer

FROGG high-risk prostate cancer workshop: patterns of practice and literature review: part I: intact prostate

Australian and New Zealand radiation oncologists with an interest in uro-oncology were invited to participate in a pattern-of-practice survey dealing with the management of intact high-risk prostate cancer. Responses from 46 practitioners (representing 73% of all potential respondents) revealed that high-dose radiation therapy is the standard of care. However, there is variability in practice with regard to the methods used to achieve dose escalation, the use of whole-pelvic radiation therapy and the optimal duration of androgen deprivation therapy employed. A review of the literature outlining the current body of knowledge and the planned and ongoing studies in intact high-risk prostate cancer is presented

Development of quality indicators to monitor radiotherapy care for men with prostate cancer: A modified Delphi method

BACKGROUND AND PURPOSE: Quality indicators (QIs) have been developed for many aspects of prostate cancer care, but are under-developed with regard to radiotherapy treatment. We aimed to develop a valid, relevant and feasible set of core QIs to measure quality of radiotherapy care in men with prostate cancer.MATERIALS AND METHODS: We used a RAND-modified Delphi process to select QIs that were regarded as both important and feasible measures of quality radiotherapy care. This involved two phases: (1) a literature review to identify a list of proposed QIs; and (2) a QI selection process by an expert panel (n = 12) conducted in a series of three rounds: two online questionnaires' and one face-to-face meeting. The RAND criterion identified variation in ratings and determined the level of agreement after each round of voting.RESULTS: A total of 144 candidate QIs, which included measures from pre-treatment to post-treatment and survivorship care were identified. After three rounds of voting, the panel approved a comprehensive set of 17 QIs, with most assessing a process of care (n = 16, 94.1%) and the remaining assessing a health outcome.CONCLUSION: This study developed a core set of 17 QIs which will be used to report from the Prostate Cancer Outcomes Registry-Australia &amp; New Zealand, to monitor the quality of radiotherapy care prostate cancer patients receive.</p

Australian & New Zealand Faculty of Radiation Oncology Genito-Urinary Group: 2011 consensus guidelines for curative radiotherapy for urothelial carcinoma of the bladder

Curative radiotherapy, with or without concurrent chemotherapy, is recognized as a standard treatment option for muscle-invasive bladder cancer. It is commonly used for two distinct groups of patients: either for those medically unfit for surgery, or as part of a bladder preserving management plan incorporating the possibility of salvage cystectomy. However, in both situations, the approach to radiotherapy varies widely around the world. The Australian and New Zealand Faculty of Radiation Oncology Genito-Urinary Group recognised a need to develop consistent, evidence-based guidelines for patient selection and radiotherapy technique in the delivery of curative radiotherapy. Following a workshop convened in May 2009, a working party collated opinions and conducted a wide literature appraisal linking each recommendation with the best available evidence. This process was subject to ongoing re-presentation to the Faculty of Radiation Oncology Genito-Urinary Group members prior to final endorsement. These Guidelines include patient selection, radiation target delineation, dose and fractionation schedules, normal tissue constraints and investigational techniques. Particular emphasis is given to the rationale for the target volumes described. These Guidelines provide a consensus-based framework for the delivery of curative radiotherapy for muscle-invasive bladder cancer. Widespread input from radiation oncologists treating bladder cancer ensures that these techniques are feasible in practice. We recommend these Guidelines be adopted widely in order to encourage a uniformly high standard of radiotherapy in this setting, and to allow for better comparison of outcomes

DNA methylation changes following DNA damage in prostate cancer cells

Many cancer therapies operate by inducing double-strand breaks (DSBs) in cancer cells, however treatment-resistant cells rapidly initiate mechanisms to repair damage enabling survival. While the DNA repair mechanisms responsible for cancer cell survival following DNA damaging treatments are becoming better understood, less is known about the role of the epigenome in this process. Using prostate cancer cell lines with differing sensitivities to radiation treatment, we analysed the DNA methylation profiles prior to and following a single dose of radiotherapy (RT) using the Illumina Infinium HumanMethylation450 BeadChip platform. DSB formation and repair, in the absence and presence of the DNA hypomethylating agent, 5-azacytidine (5-AzaC), were also investigated using γH2A.X immunofluorescence staining. Here we demonstrate that DNA methylation is generally stable following a single dose of RT; however, a small number of CpG sites are stably altered up to 14 d following exposure. While the radioresistant and radiosensitive cells displayed distinct basal DNA methylation profiles, their susceptibility to DNA damage appeared similar demonstrating that basal DNA methylation has a limited influence on DSB induction at the regions examined. Recovery from DSB induction was also similar between these cells. Treatment with 5-AzaC did not sensitize resistant cells to DNA damage, but rather delayed recruitment of phosphorylated BRCA1 (S1423) and repair of DSBs. These results highlight that stable epigenetic changes are possible following a single dose of RT and may have significant clinical implications for cancer treatment involving recurrent or fractionated dosing regimens

The outcome of a multi-centre feasibility study of online adaptive radiotherapy for muscle-invasive bladder cancer TROG 10.01 BOLART

Purpose: To assess whether online adaptive radiotherapy for bladder cancer is feasible across multiple Radiation Oncology departments using different imaging, delivery and recording technology

Radiotherapy for node-positive prostate cancer: 2019 Recommendations of the Australian and New Zealand Radiation Oncology Genito-Urinary group

The management of node-positive prostate cancer is highly variable, with both locoregional and systemic treatment options available. With the increasing use of novel imaging techniques such as PSMA-PET and MRI, combined with the increasing use of surgery for high-risk prostate cancer, clinical and pathological regional nodal disease is being detected at a higher rate and at an earlier stage than previously. This creates a window for a potentially curative management approach. The role of radiotherapy including optimal radiation target volumes and dose, as well as the timing and duration of accompanying systemic therapy remains uncertain. At a workshop in 2017, the Australian and New Zealand Faculty of Radiation Oncology Genito-Urinary Group (FROGG) identified variations in the management of node-positive prostate cancer identified on primary staging or on histopathology at radical prostatectomy. FROGG reviewed the literature and developed a set of evidence-based recommendations on the appropriate investigation and management of clinically and pathologically node-positive prostate cancer. These recommendations encompass imaging techniques, radiation treatment target volumes and doses, as well as the use of androgen deprivation therapy

Evaluation of Hypofractionated Radiation Therapy Use and Patient-Reported Outcomes in Men with Nonmetastatic Prostate Cancer in Australia and New Zealand

Importance: Randomized clinical trials in prostate cancer have reported noninferior outcomes for hypofractionated radiation therapy (HRT) compared with conventional RT (CRT); however, uptake of HRT across jurisdictions is variable. Objective: To evaluate the use of HRT vs CRT in men with nonmetastatic prostate cancer and compare patient-reported outcomes (PROs) at a population level. Design, Setting, and Participants: Registry-based cohort study from the Australian and New Zealand Prostate Cancer Outcomes Registry (PCOR-ANZ). Participants were men with nonmetastatic prostate cancer treated with primary RT (excluding brachytherapy) from January 2016 to December 2019. Data were analyzed in March 2021. Exposures: HRT defined as 2.5 to 3.3 Gy and CRT defined as 1.7 to 2.3 Gy per fraction. Main Outcomes and Measures: Temporal trends and institutional, clinicopathological, and sociodemographic factors associated with use of HRT were analyzed. PROs were assessed 12 months following RT using the Expanded Prostate Cancer Index Composite (EPIC)-26 Short Form questionnaire. Differences in PROs were analyzed by adjusting for age and National Comprehensive Cancer Network risk category. Results: Of 8305 men identified as receiving primary RT, 6368 met the inclusion criteria for CRT (n = 4482) and HRT (n = 1886). The median age was 73.1 years (IQR, 68.2-77.3 years), 2.6% (168) had low risk, 45.7% (2911) had intermediate risk, 44.5% (2836) had high-/very high-risk, and 7.1% (453) had regional nodal disease. Use of HRT increased from 2.1% (9 of 435) in the first half of 2016 to 52.7% (539 of 1023) in the second half of 2019, with lower uptake in the high-/very high-risk (1.9% [4 of 215] to 42.4% [181 of 427]) compared with the intermediate-risk group (2.2% [4 of 185] to 67.6% [325 of 481]) (odds ratio, 0.26; 95% CI, 0.15-0.45). Substantial variability in the use of HRT for intermediate-risk disease remained at the institutional level (median 53.3%; range, 0%-100%) and clinician level (median 57.9%; range, 0%-100%) in the last 2 years of the study period. There were no clinically significant differences across EPIC-26 urinary and bowel functional domains or bother scores. Conclusions and Relevance: In this cohort study, use of HRT for prostate cancer increased substantially from 2016. This population-level data demonstrated clinically equivalent PROs and supports the continued implementation of HRT into routine practice. The wide variation in practice observed at the jurisdictional, institutional, and clinician level provides stakeholders with information that may be useful in targeting implementation strategies and benchmarking services.</p