Clinical service delivery implications of the COVID-19 pandemic on people with Inflammatory bowel disease: a qualitative study.

BACKGROUND: During the COVID-19 pandemic, clinical services were severely disrupted, restricted, or withdrawn across the country. People living with Inflammatory Bowel Disease (IBD) - an auto-immune disorder for which medical treatment often results in immunosuppression, thus requiring regular monitoring-may have struggled to access clinical support. As part of a larger qualitative study, we investigated experiences of access to clinical services during the pandemic, and patient concerns about and preferences for services in the future. METHODS: This exploratory qualitative study used semi-structured interviews to explore participants' experiences of clinical services across the UK during the pandemic. All data were collected remotely (March - May 2021) using online video-calling platforms or by telephone. Audio files were transcribed professionally and anonymised for analysis. Data were analysed using thematic analysis. RESULTS: Of the eight themes found across all data, four related specifically to accessing GP, local (district) hospital, and specialist (tertiary) referral services for IBD: 1) The Risk of Attending Hospital; 2) Missing Routine Monitoring or Treatment; 3) Accessing Care as Needed, and 4) Remote Access and The Future. CONCLUSIONS: Our findings support other studies reporting changes in use of health services, and concerns about future remote access methods. Maintenance of IBD services in some form is essential throughout crisis periods; newly diagnosed patients need additional support; future dependence on IBD services could be reduced through use of treatment / self-management plans. As the NHS digitalises it's future services, the mode of appointment-remote (telephone, video call), or in-person - needs to be flexible and suit the patient.

Event-free survival after radical prostatectomy according to prostate-specific membrane antigen-positron emission tomography and European Association of Urology biochemical recurrence risk groups.

OBJECTIVE: To assess European Association of Urology (EAU) risk groups for biochemical recurrence (BCR) of prostate cancer relative to prostate-specific membrane antigen-positron emission tomography (PSMA-PET) status and oncological outcomes. PATIENTS AND METHODS: A retrospective analysis of a study that incorporated PSMA-PET for men with BCR after radical prostatectomy (RP) was undertaken. EAU risk groups were considered relative to clinical variables, PSMA-PET findings, and deployment of salvage radiotherapy (SRT). The primary oncological outcome was event-free survival (EFS) and this was analysed relative to clinical and imaging variables. An 'event' occurred if prostate-specific antigen (PSA) level rose >0.2 ng/mL above nadir or additional therapies were introduced. RESULTS: A total of 137 patients were included, most of whom had EAU high-risk disease (76%) and/or low PSA levels (80% <0.5 ng/mL) at the time of PSMA-PET. EAU risk group was not associated with regional nodal/distant metastasis on PSMA-PET. Regional nodal/distant metastasis on PSMA PET (compared to negative/local recurrence: hazard ratio [HR] 2.2; P = 0.002) and SRT use (vs no SRT: HR 0.44; P = 0.004) were associated with EFS. EAU high-risk status was not significantly associated with worse EFS (HR 1.7, P = 0.12) compared to EAU low-risk status. Among patients who received SRT, both regional/distant metastasis on PSMA-PET (HR 3.1; P < 0.001) and EAU high-risk status (HR 2.9; P = 0.04) were independently associated with worse EFS, which was driven by patients in the EAU high-risk group with regional/distant metastases (38%; HR 3.1, P = 0.001). CONCLUSIONS: In patients with post-RP BCR, PSMA-PET findings and receipt of SRT predicted EFS. In patients receiving SRT, PSMA status combined with EAU risk grouping was most predictive of EFS. These findings suggest that the EAU risk groups could be improved with the addition of PSMA-PET.

The role of staging laparoscopy in pancreatic adenocarcinoma and its effect on patients' survival.

BACKGROUND: Prompt and accurate staging of pancreatic cancer is essential to distinguish patients to benefit from resection with curative intent and those with unresectable disease. A staging laparoscopy is used preoperatively to identify macroscopic or occult metastases not identified on imaging. This single-institution study aims to evaluate the role of staging laparoscopy in patients with pancreatic adenocarcinoma and its effect on overall survival. METHOD: Clinicopathologic data were evaluated for all patients undergoing staging laparoscopy for pancreatic adenocarcinoma from July 2014 to December 2019. The study identified 155 patients eligible for analysis. All patients were followed for at least 2 years. Clinical backgrounds, survival curves and prognostic factors were investigated. RESULTS: Resectability status among the cohort was 62 (40%) upfront resectable, 53 (34%) borderline resectable and 40 (26%) locally advanced disease. The median age was 69, with 44% male patients. Median CA19-9 value was 125 kU/L, and median CA125 value was 22 kU/L. Staging laparoscopy resulted in upstaging nine (15%) upfront resectable patients, five (9%) borderline resectable patients and ten (25%) locally advanced patients. There was positive cytology in 19 (12%), peritoneal deposits in six (4%) and peritoneal liver deposits in seven (5%) patients. Overall, the number needed to treat (NNT) to avoid an unnecessary laparotomy was eight patients. CONCLUSION: Staging laparoscopy continues to be a valuable investigation of pancreatic adenocarcinoma. In this institution, one in every eight patients undergoing a staging laparoscopy was upstaged to metastatic disease, thus avoiding an unnecessary laparotomy or a non-curative resection.

Adjuvant or early salvage radiotherapy for the treatment of localised and locally advanced prostate cancer: a prospectively planned systematic review and meta-analysis of aggregate data.

BACKGROUND: It is unclear whether adjuvant or early salvage radiotherapy following radical prostatectomy is more appropriate for men who present with localised or locally advanced prostate cancer. We aimed to prospectively plan a systematic review of randomised controlled trials (RCTs) comparing these radiotherapy approaches. METHODS: We used a prospective framework for adaptive meta-analysis (FAME), starting the review process while eligible trials were ongoing. RCTs were eligible if they aimed to compare immediate adjuvant radiotherapy versus early salvage radiotherapy, following radical prostatectomy in men (age ≥18 years) with intermediate-risk or high-risk, localised or locally advanced prostate cancer. We searched trial registers and conference proceedings until July 8, 2020, to identify eligible RCTs. By establishing the ARTISTIC collaboration with relevant trialists, we were able to anticipate when eligible trial results would emerge, and we developed and registered a protocol with PROSPERO before knowledge of the trial results (CRD42019132669). We used a harmonised definition of event-free survival, as the time from randomisation until the first evidence of either biochemical progression (prostate-specific antigen [PSA] ≥0·4 ng/mL and rising after completion of any postoperative radiotherapy), clinical or radiological progression, initiation of a non-trial treatment, death from prostate cancer, or a PSA level of at least 2·0 ng/mL at any time after randomisation. We predicted when we would have sufficient power to assess whether adjuvant radiotherapy was superior to early salvage radiotherapy. Investigators supplied results for event-free survival, both overall and within predefined patient subgroups. Hazard ratios (HRs) for the effects of radiotherapy timing on event-free survival and subgroup interactions were combined using fixed-effect meta-analysis. FINDINGS: We identified three eligible trials and were able to obtain updated results for event-free survival for 2153 patients recruited between November, 2007, and December, 2016. Median follow-up ranged from 60 months to 78 months, with a maximum follow-up of 132 months. 1075 patients were randomly assigned to receive adjuvant radiotherapy and 1078 to a policy of early salvage radiotherapy, of whom 421 (39·1%) had commenced treatment at the time of analysis. Patient characteristics were balanced within trials and overall. Median age was similar between trials at 64 or 65 years (with IQRs ranging from 59 to 68 years) across the three trials and most patients (1671 [77·6%]) had a Gleason score of 7. All trials were assessed as having low risk of bias. Based on 270 events, the meta-analysis showed no evidence that event-free survival was improved with adjuvant radiotherapy compared with early salvage radiotherapy (HR 0·95, 95% CI 0·75-1·21; p=0·70), with only a 1 percentage point (95% CI -2 to 3) change in 5-year event-free survival (89% vs 88%). Results were consistent across trials (heterogeneity p=0·18; I2=42%). INTERPRETATION: This collaborative and prospectively designed systematic review and meta-analysis suggests that adjuvant radiotherapy does not improve event-free survival in men with localised or locally advanced prostate cancer. Until data on long-term outcomes are available, early salvage treatment would seem the preferable treatment policy as it offers the opportunity to spare many men radiotherapy and its associated side-effects. FUNDING: UK Medical Research Council.

AGITG MASTERPLAN: a randomised phase II study of modified FOLFIRINOX alone or in combination with stereotactic body radiotherapy for patients with high-risk and locally advanced pancreatic cancer.

BACKGROUND: Among patients with non-metastatic pancreatic cancer, 80% have high-risk, borderline resectable or locally advanced cancer, with a 5-year overall survival of 12%. MASTERPLAN evaluates the safety and activity of stereotactic body radiotherapy (SBRT) in addition to chemotherapy in these patients. METHODS AND DESIGN: MASTERPLAN is a multi-centre randomised phase II trial of 120 patients with histologically confirmed potentially operable pancreatic cancer (POPC) or inoperable pancreatic cancer (IPC). POPC includes patients with borderline resectable or high-risk tumours; IPC is defined as locally advanced or medically inoperable pancreatic cancer. Randomisation is 2:1 to chemotherapy + SBRT (investigational arm) or chemotherapy alone (control arm) by minimisation and stratified by patient cohort (POPC v IPC), planned induction chemotherapy and institution. Chemotherapy can have been commenced ≤28 days prior to randomisation. Both arms receive 6 × 2 weekly cycles of modified FOLFIRINOX (oxaliplatin (85 mg/m2 IV), irinotecan (150 mg/m2), 5-fluorouracil (2400 mg/m2 CIV), leucovorin (50 mg IV bolus)) plus SBRT in the investigational arm. Gemcitabine+nab-paclitaxel is permitted for patients unsuitable for mFOLFIRINOX. SBRT is 40Gy in five fractions with planning quality assurance to occur in real time. Following initial chemotherapy ± SBRT, resectability will be evaluated. For resected patients, adjuvant chemotherapy is six cycles of mFOLFIRINOX. Where gemcitabine+nab-paclitaxel was used initially, the adjuvant treatment is 12 weeks of gemcitabine and capecitabine or mFOLFIRINOX. Unresectable or medically inoperable patients with stable/responding disease will continue with a further six cycles of mFOLFIRINOX or three cycles of gemcitabine+nab-paclitaxel, whatever was used initially. The primary endpoint is 12-month locoregional control. Secondary endpoints are safety, surgical morbidity and mortality, radiological response rates, progression-free survival, pathological response rates, surgical resection rates, R0 resection rate, quality of life, deterioration-free survival and overall survival. Tertiary/correlative objectives are radiological measures of nutrition and sarcopenia, and serial tissue, blood and microbiome samples to be assessed for associations between clinical endpoints and potential predictive/prognostic biomarkers. Interim analysis will review rates of locoregional recurrence, distant failure and death after 40 patients complete 12 months follow-up. Fifteen Australian and New Zealand sites will recruit over a 4-year period, with minimum follow-up period of 12 months. DISCUSSION: MASTERPLAN evaluates SBRT in both resectable and unresectable patients with pancreatic ductal adenocarcinoma. TRIAL REGISTRATION: Australia New Zealand Clinical Trials Registry ACTRN12619000409178 , 13/03/2019. Protocol version: 2.0, 19 May 2019.

Prostate cancer survivorship essentials framework: guidelines for practitioners.

OBJECTIVE: To develop contemporary and inclusive prostate cancer survivorship guidelines for the Australian setting. PARTICIPANTS AND METHODS: A four-round iterative policy Delphi was used, with a 47-member expert panel that included leaders from key Australian and New Zealand clinical and community groups and consumers from diverse backgrounds, including LGBTQIA people and those from regional, rural and urban settings. The first three rounds were undertaken using an online survey (94-96% response) followed by a fourth final face-to-face panel meeting. Descriptors for men's current prostate cancer survivorship experience were generated, along with survivorship elements that were assessed for importance and feasibility. From these, survivorship domains were generated for consideration. RESULTS: Six key descriptors for men's current prostate cancer survivorship experience that emerged were: dealing with side effects; challenging; medically focused; uncoordinated; unmet needs; and anxious. In all, 26 survivorship elements were identified within six domains: health promotion and advocacy; shared management; vigilance; personal agency; care coordination; and evidence-based survivorship interventions. Consensus was high for all domains as being essential. All elements were rated high on importance but consensus was mixed for feasibility. Seven priorities were derived for immediate action. CONCLUSION: The policy Delphi allowed a uniquely inclusive expert clinical and community group to develop prostate cancer survivorship domains that extend beyond traditional healthcare parameters. These domains provide guidance for policymakers, clinicians, community and consumers on what is essential for step change in prostate cancer survivorship outcomes.

Adjuvant radiotherapy versus early salvage radiotherapy following radical prostatectomy (TROG 08.03/ANZUP RAVES): a randomised, controlled, phase 3, non-inferiority trial.

BACKGROUND: Adjuvant radiotherapy has been shown to halve the risk of biochemical progression for patients with high-risk disease after radical prostatectomy. Early salvage radiotherapy could result in similar biochemical control with lower treatment toxicity. We aimed to compare biochemical progression between patients given adjuvant radiotherapy and those given salvage radiotherapy. METHODS: We did a phase 3, randomised, controlled, non-inferiority trial across 32 oncology centres in Australia and New Zealand. Eligible patients were aged at least 18 years and had undergone a radical prostatectomy for adenocarcinoma of the prostate with pathological staging showing high-risk features defined as positive surgical margins, extraprostatic extension, or seminal vesicle invasion; had an Eastern Cooperative Oncology Group performance status of 0-1, and had a postoperative prostate-specific antigen (PSA) concentration of 0·10 ng/mL or less. Patients were randomly assigned (1:1) using a minimisation technique via an internet-based, independently generated allocation to either adjuvant radiotherapy within 6 months of radical prostatectomy or early salvage radiotherapy triggered by a PSA of 0·20 ng/mL or more. Allocation sequence was concealed from investigators and patients, but treatment assignment for individual randomisations was not masked. Patients were stratified by radiotherapy centre, preoperative PSA, Gleason score, surgical margin status, and seminal vesicle invasion status. Radiotherapy in both groups was 64 Gy in 32 fractions to the prostate bed without androgen deprivation therapy with real-time review of plan quality on all cases before treatment. The primary endpoint was freedom from biochemical progression. Salvage radiotherapy would be deemed non-inferior to adjuvant radiotherapy if freedom from biochemical progression at 5 years was within 10% of that for adjuvant radiotherapy with a hazard ratio (HR) for salvage radiotherapy versus adjuvant radiotherapy of 1·48. The primary analysis was done on an intention-to-treat basis. This study is registered with ClinicalTrials.gov, NCT00860652. FINDINGS: Between March 27, 2009, and Dec 31, 2015, 333 patients were randomly assigned (166 to adjuvant radiotherapy; 167 to salvage radiotherapy). Median follow-up was 6·1 years (IQR 4·3-7·5). An independent data monitoring committee recommended premature closure of enrolment because of unexpectedly low event rates. 84 (50%) patients in the salvage radiotherapy group had radiotherapy triggered by a PSA of 0·20 ng/mL or more. 5-year freedom from biochemical progression was 86% (95% CI 81-92) in the adjuvant radiotherapy group versus 87% (82-93) in the salvage radiotherapy group (stratified HR 1·12, 95% CI 0·65-1·90; pnon-inferiority=0·15). The grade 2 or worse genitourinary toxicity rate was lower in the salvage radiotherapy group (90 [54%] of 167) than in the adjuvant radiotherapy group (116 [70%] of 166). The grade 2 or worse gastrointestinal toxicity rate was similar between the salvage radiotherapy group (16 [10%]) and the adjuvant radiotherapy group (24 [14%]). INTERPRETATION: Salvage radiotherapy did not meet trial specified criteria for non-inferiority. However, these data support the use of salvage radiotherapy as it results in similar biochemical control to adjuvant radiotherapy, spares around half of men from pelvic radiation, and is associated with significantly lower genitourinary toxicity. FUNDING: New Zealand Health Research Council, Australian National Health Medical Research Council, Cancer Council Victoria, Cancer Council NSW, Auckland Hospital Charitable Trust, Trans-Tasman Radiation Oncology Group Seed Funding, Cancer Research Trust New Zealand, Royal Australian and New Zealand College of Radiologists, Cancer Institute NSW, Prostate Cancer Foundation Australia, and Cancer Australia.

Monitoring quality of care for patients with pancreatic cancer: a modified Delphi consensus.

BACKGROUND: Best practise care optimises survival and quality of life in patients with pancreatic cancer (PC), but there is evidence of variability in management and suboptimal care for some patients. Monitoring practise is necessary to underpin improvement initiatives. We aimed to develop a core set of quality indicators that measure quality of care across the disease trajectory. METHODS: A modified, three-round Delphi survey was performed among experts with wide experience in PC care across three states in Australia. A total of 107 potential quality indicators were identified from the literature and divided into five areas: diagnosis and staging, surgery, other treatment, patient management and outcomes. A further six indicators were added by the panel, increasing potential quality indicators to 113. Rated on a scale of 1-9, indicators with high median importance and feasibility (score 7-9) and low disagreement (<1) were considered in the candidate set. RESULTS: From 113 potential quality indicators, 34 indicators met the inclusion criteria and 27 (7 diagnosis and staging, 5 surgical, 4 other treatment, 5 patient management, 6 outcome) were included in the final set. CONCLUSIONS: The developed indicator set can be applied as a tool for internal quality improvement, comparative quality reporting, public reporting and research in PC care.

Stereotactic prostate adaptive radiotherapy utilising kilovoltage intrafraction monitoring: the TROG 15.01 SPARK trial.

BACKGROUND: This paper describes the multi-institutional prospective phase II clinical trial, SPARK: Stereotactic Prostate Adaptive Radiotherapy utilizing Kilovoltage Intrafraction Monitoring (KIM). KIM is a real-time image guided radiotherapy technology being developed and clinically pioneered for prostate cancer treatment in Australia. It has potential for widespread use for target radiotherapy treatment of cancers of the pelvis, thorax and abdomen. METHODS: In the SPARK trial we will measure the cancer targeting accuracy and patient outcomes for 48 prostate cancer patients who will be treated in five treatment sessions as opposed to the conventional 40 sessions. The reduced number of treatment sessions is enabled by the KIM's increased cancer targeting accuracy. DISCUSSION: Real-time imaging in radiotherapy has the potential to decrease the time taken during cancer treatment and reduce the imaging dose required. With the imaging being acquired during the treatment, and the analysis being automated, there is potential for improved throughput. The SPARK trial will be conducted under the auspices of the Trans-Tasman Radiation Oncology Group (TROG). TRIAL REGISTRATION: This trial was registered on ClinicalTrials.gov on 09 March 2015. The identifier is: NCT02397317.

Knowledge, attitudes and beliefs towards management of men with locally advanced prostate cancer following radical prostatectomy: an Australian survey of urologists.

OBJECTIVE: To investigate Australian urologists' knowledge, attitudes and beliefs, and the association of these with treatment preferences relating to guideline-recommended adjuvant radiotherapy for men with adverse pathologic features following radical prostatectomy. SUBJECTS AND METHODS: A nationwide mailed and web-based survey of Australian urologist members of the Urological Society of Australia and New Zealand (USANZ). RESULTS: 157 surveys were included in the analysis (45% response rate). Just over half of respondents (54%) were aware of national clinical practice guidelines for the management of prostate cancer. Urologists' attitudes and beliefs towards the specific recommendation for post-operative adjuvant radiotherapy for men with locally advanced prostate cancer were mixed. Just over half agreed the recommendation is based on a valid interpretation of the underpinning evidence (54.1%, 95% CI [46%, 62.2%]) but less than one third agreed adjuvant radiotherapy will lead to improved patient outcomes (30.2%, 95% CI [22.8%, 37.6%]). Treatment preferences were varied, demonstrating clinical equipoise. A positive attitude towards the clinical practice recommendation was significantly associated with treatment preference for adjuvant radiotherapy (rho = 0.520, P < 0.0001). There was stronger preference for adjuvant radiotherapy in more recently trained urologists (registrars) while preference for watchful waiting was greater in more experienced urologists (consultants) (b = 0.156, P = 0.034; 95% CI [0.048, 1.24]). Urologists' attitudes towards clinical practice guidelines in general were positive. CONCLUSION: There remains clinical equipoise among Australian urologists in relation to adjuvant radiotherapy for men with adverse pathologic features following radical prostatectomy.

(68) Ga-PSMA has a high detection rate of prostate cancer recurrence outside the prostatic fossa in patients being considered for salvage radiation treatment.

OBJECTIVES: To examine the detection rates of (68) Ga-PSMA-positron emission tomography (PET)/computed tomography (CT) in patients with biochemical recurrence (BCR) after radical prostatectomy (RP), and also the impact on their management. MATERIALS AND METHODS: A total of 300 consecutive patients with prostate cancer (PCa) who underwent (68) Ga-PSMA-PET/CT between February and July 2015 were prospectively included in the Prostate Cancer Imaging (ProCan-I) database. For the present analysis, we included patients with BCR (prostate-specific antigen [PSA] level ≥0.05 and <1.0 ng/mL) after RP, who were being considered for salvage radiation therapy (RT) according to the Faculty of Radiation Oncology Genito-Urinary Group (FROGG) guidelines. Two readers assessed each (68) Ga-PSMA-PET/CT, and all positive lesions were assigned to an anatomical location. For each patient, the clinical and pathological features were recorded, their association with pathological (68) Ga-PSMA uptake was investigated, and detection rates were determined according to PSA level. RESULTS: A total of 70 patients were included, and 53 positive (68) Ga-PSMA lesions were detected in 38 (54%) patients. Among patients with PSA levels 0.05-0.09 ng/mL, 8% were definitely positive; the corresponding percentages for the other PSA ranges were as follows: PSA 0.1-0.19 ng/mL, 23%; PSA 0.2-0.29 ng/mL, 58%; PSA 0.3-0.49 ng/mL, 36%; and PSA 0.5-0.99 ng/mL, 57%. Eighteen of 70 patients (27%) had pathological (68) Ga-PSMA uptake in the prostatic fossa, 11 (14.3%) in the pelvic nodes, and five (4.3%) in both the fossa and pelvic lymph nodes. Finally, there was uptake outside the pelvis with or without a lesion in the fossa or pelvic lymph nodes in four cases (8.6%). As a result of the (68) Ga-PSMA findings there was a major management change in 20 (28.6%) patients. CONCLUSIONS: (68) Ga-PSMA appears to be useful for re-staging of PCa in patients with rising PSA levels who are being considered for salvage RT even at PSA levels <0.5 ng/mL. These results underline the need for further prospective trials to evaluate the changes in RT volume or management attributable to (68) Ga-PSMA findings.

A Phase III trial to investigate the timing of radiotherapy for prostate cancer with high-risk features: background and rationale of the Radiotherapy -- Adjuvant Versus Early Salvage (RAVES) trial.

OBJECTIVES: To test the hypothesis that observation with early salvage radiotherapy (SRT) is not inferior to 'standard' treatment with adjuvant RT (ART) with respect to biochemical failure in patients with pT3 disease and/or positive surgical margins (SMs) after radical prostatectomy (RP). To compare the following secondary endpoints between the two arms: patient-reported outcomes, adverse events, biochemical failure-free survival, overall survival, disease-specific survival, time to distant failure, time to local failure, cost utility analysis, quality adjusted life years and time to androgen deprivation. PATIENTS AND METHODS: The Radiotherapy - Adjuvant Versus Early Salvage (RAVES) trial is a phase III multicentre randomised controlled trial led by the Trans Tasman Radiation Oncology Group (TROG), in collaboration with the Urological Society of Australia and New Zealand (USANZ), and the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP). In all, 470 patients are planned to be randomised 1:1 to either ART commenced at ≤4 months of RP (standard of care) or close observation with early SRT triggered by a PSA level of >0.20 ng/mL (experimental arm). Eligible patients have had a RP for adenocarcinoma of the prostate with at least one of the following risk factors: positive SMs ± extraprostatic extension ± seminal vesicle involvement. The postoperative PSA level must be ≤0.10 ng/mL. Rigorous investigator credentialing and a quality assurance programme are designed to promote consistent RT delivery among patients. RESULTS: Trial is currently underway, with 258 patients randomised as of 31 October 2013. International collaborations have developed, including a planned meta-analysis to be undertaken with the UK Medical Research Council/National Cancer Institute of Canada Clinical Trials Group RADICALS (Radiotherapy and Androgen Deprivation In Combination with Local Surgery) trial and an innovative psycho-oncology sub-study to investigate a patient decision aid resource. CONCLUSION: On the current evidence available, it remains unclear if ART is equivalent or superior to observation with early SRT.

Prognostic impact of prostate-specific membrane antigen positron emission tomography (PSMA PET) staging for clinically node-positive prostate cancer.

INTRODUCTION: In the current American Joint Committee on Cancer staging system, patients with pelvic nodal metastases are considered stage IV prostate cancer. This study aims to investigate whether men with prostate-specific membrane antigen positron emission tomography (PSMA PET)-detected pelvic node-positive prostate cancer at diagnosis have a better outcome compared to men with node-positive disease identified on conventional imaging. METHODS: This is a retrospective cohort study comparing the outcomes of men with node-positive prostate cancer and disease confined to the pelvis, staged with conventional versus PSMA PET imaging. Men had to be treated definitively with a combination of androgen deprivation therapy and radiation treatment to the prostate and pelvic lymph nodes. Kaplan-Meier and Cox regression analysis was used to compare biochemical failure-free survival (BFFS) and overall survival (OS). RESULTS: Seventy-six men with nodal metastases confined to the pelvis were identified. Fifty-one were detected with PSMA PET while 25 were staged with conventional imaging. PSMA PET staged patients had a lower proportion of Gleason 8-10 disease (78% vs. 96%) as well as a lower median prostate-specific antigen (11 ng/mL vs. 26 ng/mL). BFFS at 4 years was 72% with PSMA PET-detected node-positive disease vs. 38% with conventionally detected node-positive disease. Four-year OS was 93% with PSMA PET staged patients vs. 76% with conventionally staged patients. On multivariate analysis, the PSMA PET staged group was associated with improved BFFS (Adjusted HR = 3.00, 95% CI 1.43, 6.29, P = 0.004) and OS (Adjusted HR = 5.81, 95% CI 1.43, 23.7, P = 0.007). CONCLUSION: Men with PSMA PET-detected node-positive prostate cancer confined to the pelvis have significantly better biochemical control and survival compared to those with node-positive pelvic disease identified through conventional staging.

Robustness of magnetic resonance imaging and positron emission tomography radiomic features in prostate cancer: Impact on recurrence prediction after radiation therapy.

Background and purpose: Radiomic features from MRI and PET are an emerging tool with potential to improve prostate cancer outcomes. However, feature robustness due to image segmentation variations is currently unknown. Therefore, this study aimed to evaluate the robustness of radiomic features with segmentation variations and their impact on predicting biochemical recurrence (BCR). Materials and methods: Multi-scanner, pre-radiation therapy imaging from 142 patients with localised prostate cancer was used. Imaging included T2-weighted (T2), apparent diffusion coefficient (ADC) MRI, and prostate-specific membrane antigen (PSMA)-PET. The prostate gland and intraprostatic tumours were manually and automatically segmented, and differences were quantified using Dice Coefficient (DC). Radiomic features including shape, first-order, and texture features were extracted for each segmentation from original and filtered images. Intraclass Correlation Coefficient (ICC) and Mean Absolute Percentage Difference (MAPD) were used to assess feature robustness. Random forest (RF) models were developed for each segmentation using robust features to predict BCR. Results: Prostate gland segmentations were more consistent (mean DC = 0.78) than tumour segmentations (mean DC = 0.46). 112 (3.6 %) radiomic features demonstrated 'excellent' robustness (ICC > 0.9 and MAPD < 1 %), and 480 features (15.4 %) demonstrated 'good' robustness (ICC > 0.75 and MAPD < 5 %). PET imaging provided more features with excellent robustness than T2 and ADC. RF models showed strong predictive power for BCR with a mean area under the receiver-operator-characteristics curve (AUC) of 0.89 (range 0.85-0.93). Conclusion: When using radiomic features for predictive modelling, segmentation variability should be considered. To develop BCR predictive models, radiomic features from the entire prostate gland are preferable over tumour segmentation-based features.

Evaluating the relationship between contouring variability and modelled treatment outcome for prostate bed radiotherapy.

Objectives.Contouring similarity metrics are often used in studies of inter-observer variation and automatic segmentation but do not provide an assessment of clinical impact. This study focused on post-prostatectomy radiotherapy and aimed to (1) identify if there is a relationship between variations in commonly used contouring similarity metrics and resulting dosimetry and (2) identify the variation in clinical target volume (CTV) contouring that significantly impacts dosimetry.Approach.The study retrospectively analysed CT scans of 10 patients from the TROG 08.03 RAVES trial. The CTV, rectum, and bladder were contoured independently by three experienced observers. Using these contours reference simultaneous truth and performance level estimation (STAPLE) volumes were established. Additional CTVs were generated using an atlas algorithm based on a single benchmark case with 42 manual contours. Volumetric-modulated arc therapy (VMAT) treatment plans were generated for the observer, atlas, and reference volumes. The dosimetry was evaluated using radiobiological metrics. Correlations between contouring similarity and dosimetry metrics were calculated using Spearman coefficient (Γ). To access impact of variations in planning target volume (PTV) margin, the STAPLE PTV was uniformly contracted and expanded, with plans created for each PTV volume. STAPLE dose-volume histograms (DVHs) were exported for plans generated based on the contracted/expanded volumes, and dose-volume metrics assessed.Mainresults. The study found no strong correlations between the considered similarity metrics and modelled outcomes. Moderate correlations (0.5 <Γ< 0.7) were observed for Dice similarity coefficient, Jaccard, and mean distance to agreement metrics and rectum toxicities. The observations of this study indicate a tendency for variations in CTV contraction/expansion below 5 mm to result in minor dosimetric impacts.Significance. Contouring similarity metrics must be used with caution when interpreting them as indicators of treatment plan variation. For post-prostatectomy VMAT patients, this work showed variations in contours with an expansion/contraction of less than 5 mm did not lead to notable dosimetric differences, this should be explored in a larger dataset to assess generalisability.

Uncertainty estimation using a 3D probabilistic U-Net for segmentation with small radiotherapy clinical trial datasets.

BACKGROUND AND OBJECTIVES: Bio-medical image segmentation models typically attempt to predict one segmentation that resembles a ground-truth structure as closely as possible. However, as medical images are not perfect representations of anatomy, obtaining this ground truth is not possible. A surrogate commonly used is to have multiple expert observers define the same structure for a dataset. When multiple observers define the same structure on the same image there can be significant differences depending on the structure, image quality/modality and the region being defined. It is often desirable to estimate this type of aleatoric uncertainty in a segmentation model to help understand the region in which the true structure is likely to be positioned. Furthermore, obtaining these datasets is resource intensive so training such models using limited data may be required. With a small dataset size, differing patient anatomy is likely not well represented causing epistemic uncertainty which should also be estimated so it can be determined for which cases the model is effective or not. METHODS: We use a 3D probabilistic U-Net to train a model from which several segmentations can be sampled to estimate the range of uncertainty seen between multiple observers. To ensure that regions where observers disagree most are emphasised in model training, we expand the Generalised Evidence Lower Bound (ELBO) with a Constrained Optimisation (GECO) loss function with an additional contour loss term to give attention to this region. Ensemble and Monte-Carlo dropout (MCDO) uncertainty quantification methods are used during inference to estimate model confidence on an unseen case. We apply our methodology to two radiotherapy clinical trial datasets, a gastric cancer trial (TOPGEAR, TROG 08.08) and a post-prostatectomy prostate cancer trial (RAVES, TROG 08.03). Each dataset contains only 10 cases each for model development to segment the clinical target volume (CTV) which was defined by multiple observers on each case. An additional 50 cases are available as a hold-out dataset for each trial which had only one observer define the CTV structure on each case. Up to 50 samples were generated using the probabilistic model for each case in the hold-out dataset. To assess performance, each manually defined structure was matched to the closest matching sampled segmentation based on commonly used metrics. RESULTS: The TOPGEAR CTV model achieved a Dice Similarity Coefficient (DSC) and Surface DSC (sDSC) of 0.7 and 0.43 respectively with the RAVES model achieving 0.75 and 0.71 respectively. Segmentation quality across cases in the hold-out datasets was variable however both the ensemble and MCDO uncertainty estimation approaches were able to accurately estimate model confidence with a p-value < 0.001 for both TOPGEAR and RAVES when comparing the DSC using the Pearson correlation coefficient. CONCLUSIONS: We demonstrated that training auto-segmentation models which can estimate aleatoric and epistemic uncertainty using limited datasets is possible. Having the model estimate prediction confidence is important to understand for which unseen cases a model is likely to be useful.