In vivo CRISPR screens identify a dual function of MEN1 in regulating tumor-microenvironment interactions.

Functional genomic screens in two-dimensional cell culture models are limited in identifying therapeutic targets that influence the tumor microenvironment. By comparing targeted CRISPR-Cas9 screens in a two-dimensional culture with xenografts derived from the same cell line, we identified MEN1 as the top hit that confers differential dropout effects in vitro and in vivo. MEN1 knockout in multiple solid cancer types does not impact cell proliferation in vitro but significantly promotes or inhibits tumor growth in immunodeficient or immunocompetent mice, respectively. Mechanistically, MEN1 knockout redistributes MLL1 chromatin occupancy, increasing H3K4me3 at repetitive genomic regions, activating double-stranded RNA expression and increasing neutrophil and CD8+ T cell infiltration in immunodeficient and immunocompetent mice, respectively. Pharmacological inhibition of the menin-MLL interaction reduces tumor growth in a CD8+ T cell-dependent manner. These findings reveal tumor microenvironment-dependent oncogenic and tumor-suppressive functions of MEN1 and provide a rationale for targeting MEN1 in solid cancers.

Value of Dynamic Contrast-Enhanced MRI for Grade Group Prediction in Prostate Cancer: A Radiomics Pilot Study.

RATIONALE AND OBJECTIVES: To determine the role of dynamic contrast-enhanced (DCE) MRI-radiomics in predicting the International Society of Urological Pathology Grade Group (ISUP-GG) in therapy-naïve prostate cancer (PCa) patients. MATERIALS AND METHODS: In this ethics review board-approved retrospective study on two prospective clinical trials between 2017 and 2020, 73 men with suspected/confirmed PCa were included. All participants underwent multiparametric MRI. On MRI, dominant lesions (per PI-RADS) were identified. DCE-MRI radiomic features were extracted from the segmented volumes following the image biomarker standardisation initiative (IBSI) guidelines through 14 time points. Histopathology evaluation on the cognitive-fusion targeted biopsies was set as the reference standard. Univariate regression was done to evaluate potential predictors across all calculated features. Random forest imputation was used for multivariate modelling. RESULTS: 73 index lesions were reviewed. Histopathology revealed 28, 16, 13 and 16 lesions with ISUP-GG-Negative/1/2, ISUP-GG-3, ISUP-GG-4 and ISUP-GG-5, respectively. From the extracted features, total lesion enhancement (TLE), minimum enhancement intensity and Grey-Level Run Length Matrix (GLRLM) were the most significantly different parameters among ISUP-GGs (Neg/1/2 vs 3/4 vs 5). 16 features with significant cross-sectional associations with ISUP-GGs entered the multivariate analysis. The final DCE partitioning model used only four features (lesion sphericity, TLE, GLRLM and Grey-Level Zone Length Matrix). For the binarized diagnosis (ISUP-GG≤2 vs ISUP-GG>2), the accuracy reached 81%. CONCLUSION: DCE-MRI radiomics might be used as a non-invasive tool for aiding pathological grade group prediction in therapy-naïve PCa patients, potentially adding complementary information to PI-RADS for supporting tailored diagnostic pathways and treatment planning.

Genomic Determinants Associated with Modes of Progression and Patterns of Failure in Metachronous Oligometastatic Castration-sensitive Prostate Cancer.

BACKGROUND AND OBJECTIVE: Oligometastatic castration-sensitive prostate cancer (omCSPC) represents an early state in the progression of metastatic disease for which patients experience better outcomes in comparison to those with higher disease burden. Despite the generally more indolent nature, there is still much heterogeneity, with some patients experiencing a more aggressive clinical course unexplained by clinical features alone. Our aim was to investigate correlation of tumor genomics with the mode of progression (MOP) and pattern of failure (POF) following first treatment (metastasis-directed and/or systemic therapy) for omCSPC. METHODS: We performed an international multi-institutional retrospective study of men treated for metachronous omCSPC who underwent tumor next-generation sequencing with at least 1 yr of follow-up after their first treatment. Descriptive MOP and POF results are reported with respect to the presence of genomic alterations in pathways of interest. MOP was defined as class I, long-term control (LTC; no radiographic progression at last follow-up), class II, oligoprogression (1-3 lesions), or class III, polyprogression (≥4 lesions). POF included the location of lesions at first failure. Genomic pathways of interest included TP53, ATM, RB1, BRCA1/2, SPOP, and WNT (APC, CTNNB1, RNF43). Genomic associations with MOP/POF were compared using χ2 tests. Exploratory analyses revealed that the COSMIC mutational signature and differential gene expression were also correlated with MOP/POF. Overall survival (OS) was calculated via the Kaplan-Meier method from the time of first failure. KEY FINDINGS AND CLINICAL IMPLICATIONS: We included 267 patients in our analysis; the majority had either one (47%) or two (30%) metastatic lesions at oligometastasis. The 3-yr OS rate was significantly associated with MOP (71% for polyprogression vs 91% for oligoprogression; p = 0.005). TP53 mutation was associated with a significantly lower LTC rate (27.6% vs 42.3%; p = 0.04) and RB1 mutation was associated with a high rate of polyprogression (50% vs 19.9%; p = 0.022). Regarding POF, bone failure was significantly more common with tumors harboring TP53 mutations (44.8% vs25.9%; p = 0.005) and less common with SPOP mutations (7.1% vs 31.4%; p = 0.007). Visceral failure was more common with tumors harboring either WNT pathway mutations (17.2% vs 6.8%, p = 0.05) or SPOP mutations (17.9% vs 6.3%; p = 0.04). Finally, visceral and bone failures were associated with distinct gene-expression profiles. CONCLUSIONS AND CLINICAL IMPLICATIONS: Tumor genomics provides novel insight into MOP and POF following treatment for metachronous omCSPC. Patients with TP53 and RB1 mutations have a higher likelihood of progression, and TP53, SPOP, and WNT pathway mutations may have a role in metastatic organotropism. PATIENT SUMMARY: We evaluated cancer progression after a first treatment for metastatic prostate cancer with up to five metastases. We found that mutations in certain genes were associated with the location and extent of further metastasis in these patients.

Prostate Magnetic Resonance Imaging Using the Prostate Imaging for Recurrence Reporting (PI-RR) Scoring System to Detect Recurrent Prostate Cancer: A Systematic Review and Meta-analysis.

BACKGROUND AND OBJECTIVE: Prostate Imaging for Recurrence Reporting (PI-RR) was introduced in 2021 to standardize the interpretation and reporting of multiparametric magnetic resonance imaging (MRI) for prostate cancer following whole-gland treatment. The system scores image on a scale from 1 to 5 and has shown promising results in single-center studies. The aim of our systematic review and meta-analysis was to assess the diagnostic performance of the PI-RR system in predicting the likelihood of local recurrence after whole-gland treatment. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for diagnostic test accuracy were followed. Relevant databases were searched up to December 2023. Primary studies met the eligibility criteria if they reported MRI diagnostic performance in prostate cancer recurrence using PI-RR. Diagnostic performance for MRI was assessed using two different cutoff points (≥3 or ≥4 for positivity according to the PI-RR system). A meta-analysis with a random-effects model was used to estimate pooled sensitivity and specificity values. KEY FINDINGS AND LIMITATIONS: Sixteen articles were identified for full-text reading, of which six were considered eligible, involving a total of 467 patients. Using a cutoff of PI-RR ≥3 (4 studies) for recurrent disease, the sensitivity was 77.8% (95% confidence interval [CI] 69.9-84.1%) and the specificity was 80.2% (95% CI 58.2-92.2%). Using a cutoff of PI-RR ≥4 (4 studies), the sensitivity was 61.9% (95% CI 35.6-82.7%) and the specificity was 86.6% (95% CI 75.1-93.3%). Overall, the inter-rater agreement varied from fair to excellent. CONCLUSIONS AND CLINICAL IMPLICATIONS: PI-RR is accurate in detecting local recurrence after whole-gland treatment for prostate cancer and shows fair-to-good to excellent inter-reader agreement. Overall, a PI-RR cutoff of ≥3 showed high sensitivity and specificity. PATIENT SUMMARY: We reviewed studies that reported on how good MRI scans using a scoring system called PI-RR were in detecting recurrence of prostate cancer. We found that this system shows good performance, with fair to excellent agreement between different radiologists.

Oral pimonidazole unveils clinicopathologic and epigenetic features of hypoxic tumour aggressiveness in localized prostate cancer.

BACKGROUND: Tumor hypoxia is associated with prostate cancer (PCa) treatment resistance and poor prognosis. Pimonidazole (PIMO) is an investigational hypoxia probe used in clinical trials. A better understanding of the clinical significance and molecular alterations underpinning PIMO-labeled tumor hypoxia is needed for future clinical application. Here, we investigated the clinical significance and molecular alterations underpinning PIMO-labeled tumor hypoxia in patients with localized PCa, in order to apply PIMO as a prognostic tool and to identify potential biomarkers for future clinical translation. METHODS: A total of 39 patients with localized PCa were recruited and administered oral PIMO before undergoing radical prostatectomy (RadP). Immunohistochemical staining for PIMO was performed on 37 prostatectomy specimens with staining patterns evaluated and clinical association analyzed. Whole genome bisulfite sequencing was performed using laser-capture of microdissected specimen sections comparing PIMO positive and negative tumor areas. A hypoxia related methylation molecular signature was generated by integrating the differentially methylated regions with previously established RNA-seq datasets. RESULTS: Three PIMO staining patterns were distinguished: diffuse, focal, and comedo-like. The comedo-like staining pattern was more commonly associated with adverse pathology. PIMO-defined hypoxia intensity was positively correlated with advanced pathologic stage, tumor invasion, and cribriform and intraductal carcinoma morphology. The generated DNA methylation signature was found to be a robust hypoxia biomarker, which could risk-stratify PCa patients across multiple clinical datasets, as well as be applicable in other cancer types. CONCLUSIONS: Oral PIMO unveiled clinicopathologic features of disease aggressiveness in localized PCa. The generated DNA methylation signature is a novel and robust hypoxia biomarker that has the potential for future clinical translation.

Electronic malignant bowel obstruction symptom monitoring smartphone application for patients with gynecologic cancers.

OBJECTIVES: Implementation of an interprofessional program at Princess Margaret Cancer Centre, including nurse-led proactive calls to support patients with gynecologic cancers with malignant bowel obstruction, demonstrated improved outcomes compared with historical controls. The aim of the study was to convert the proactive calls into an electronic monitoring program to assess it's feasibility and scalability in patients with gynecologic cancers with or at risk of malignant bowel obstruction. METHODS: 'My Bowels on Track' smartphone application included weekly/biweekly electronic patient-reported outcomes (PROs), educational materials, and a secure messaging system. Based on PRO answers, an alerting system flagged patients with symptoms or uncompleted PROs. Nurses tracked and called patients on receiving clinical or compliance alerts. The primary objective was to assess adherence (≥70% PRO completion per patient considered an adherent patient) in the first 2 months on the program. A secondary objective was to assess the positive predictive value (PPV) of the alerts to trigger recommendations. RESULTS: Forty patients were enrolled between August 2021 and September 2022. Median age was 64.5 years (range 29-79 years). Primary diagnosis was ovarian (75%), endometrial (17.5%), or cervical (7.5%) cancer, and 92.5% of patients were receiving systemic therapy. Median duration on the program was 55 days (range 8-121 days). The 2-month adherence was 65% (95% CI 50% to 80%) and the overall adherence was 60% (95% CI 43% to 75%). Sixty-five symptom-related alerts (75% severe, 25% moderate) were reported in 60% (24/40) of patients. There were 59 recommendations triggered by the alerts. The PPV of the alerts to trigger actions was 72% (95% CI 58% to 82%). CONCLUSIONS: This pilot electronic malignant bowel obstruction monitoring program with real-time PRO assessment was feasible, and 65% of participants were adherent during the first 2 months on the program. The PRO response-based alerting system flagged concerning symptoms in 60% of participants, with a PPV of 72% to trigger nurse-led actions and/or management recommendations. TRIAL REGISTRATION NUMBER: NCT03260647.

Rapid multi-catheter segmentation for magnetic resonance image-guided catheter-based interventions.

BACKGROUND: Magnetic resonance imaging (MRI) is the gold standard for delineating cancerous lesions in soft tissue. Catheter-based interventions require the accurate placement of multiple long, flexible catheters at the target site. The manual segmentation of catheters in MR images is a challenging and time-consuming task. There is a need for automated catheter segmentation to improve the efficiency of MR-guided procedures. PURPOSE: To develop and assess a machine learning algorithm for the detection of multiple catheters in magnetic resonance images used during catheter-based interventions. METHODS: In this work, a 3D U-Net was trained to retrospectively segment catheters in scans acquired during clinical MR-guided high dose rate (HDR) prostate brachytherapy cases. To assess confidence in segmentation, multiple AI models were trained. On clinical test cases, average segmentation results were used to plan the brachytherapy delivery. Dosimetric parameters were compared to the original clinical plan. Data was obtained from 35 patients who underwent HDR prostate brachytherapy for focal disease with a total of 214 image volumes. 185 image volumes from 30 patients were used for training using a five-fold cross validation split to divide the data for training and validation. To generate confidence measures of segmentation accuracy, five trained models were generated. The remaining five patients (29 volumes) were used to test the performance of the trained model by comparison to manual segmentations of three independent observers and assessment of dosimetric impact on the final clinical brachytherapy plans. RESULTS: The network successfully identified 95% of catheters in the test set at a rate of 0.89 s per volume. The multi-model method identified the small number of cases where AI segmentation of individual catheters was poor, flagging the need for user input. AI-based segmentation performed as well as segmentations by independent observers. Plan dosimetry using AI-segmented catheters was comparable to the original plan. CONCLUSION: The vast majority of catheters were accurately identified by AI segmentation, with minimal impact on plan outcomes. The use of multiple AI models provided confidence in the segmentation accuracy and identified catheter segmentations that required further manual assessment. Real-time AI catheter segmentation can be used during MR-guided insertions to assess deflections and for rapid planning of prostate brachytherapy.

Multi-institutional Analysis of Metastasis-directed Therapy with or Without Androgen Deprivation Therapy in Oligometastatic Castration-sensitive Prostate Cancer.

BACKGROUND: Metastasis-directed therapy (MDT) is increasingly being used in oligometastatic castration-sensitive prostate cancer (omCSPC). However, it is currently unclear how to optimally integrate MDT with the standard of care of systemic hormonal therapy. OBJECTIVE: To report long-term outcomes of MDT alone versus MDT and a defined course of androgen deprivation therapy (ADT) in omCSPC. DESIGN, SETTING, AND PARTICIPANTS: Here, a multicenter, international retrospective cohort of omCSPC as defined by conventional imaging was reported. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Biochemical progression-free survival (bPFS), distant progression-free survival (dPFS), and combined biochemical or distant progression-free survival (cPFS) were evaluated with Kaplan-Meier and multivariable Cox proportional hazard regression models. RESULTS AND LIMITATIONS: A total of 263 patients were included, 105 with MDT + ADT and 158 with MDT alone. The majority of patients had metachronous disease (90.5%). Five-year bPFS, dPFS, and cPFS were, respectively, 24%, 41%, and 19% in patients treated with MDT + ADT and 11% (hazard ratio [HR] 0.48, 95% confidence interval [CI] 0.36-0.64), 29% (HR 0.56, 95% CI 0.40-0.78), and 9% (HR 0.50, 95% CI 0.38-0.67) in patients treated with MDT alone. On a multivariable analysis adjusting for pretreatment variables, the use of ADT was associated with improved bPFS (HR 0.43, p < 0.001), dPFS (HR 0.45, p = 0.002), and cPFS (HR 0.44, p < 0.001). CONCLUSIONS: In this large multi-institutional report, the addition of concurrent ADT to MDT appears to improve time to prostate-specific antigen progression and distant recurrence, noting that about 10% patients had durable control with MDT alone. Ongoing phase 3 studies will help further define treatment options for omCSPC. PATIENT SUMMARY: Here, we report a large retrospective review evaluating the outcomes of metastasis-directed therapy with or without a limited course of androgen deprivation for patients with oligometastatic castration-sensitive prostate cancer. This international multi-institutional review demonstrates that the addition of androgen deprivation therapy to metastasis-directed therapy (MDT) improves progression-free survival. While a proportion of patients appear to have long-term disease control with MDT alone, further work in biomarker discovery is required to better identify which patients would be appropriate for de-escalated therapy.

Prospective evaluation of patient-reported anxiety and experiences with adaptive radiation therapy on an MR-linac.

Purpose: An integrated magnetic resonance scanner and linear accelerator (MR-linac) was implemented with daily online adaptive radiation therapy (ART). This study evaluated patient-reported experiences with their overall hospital care as well as treatment in the MR-linac environment. Methods: Patients pre-screened for MR eligibility and claustrophobia were referred to simulation on a 1.5 T MR-linac. Patient-reported experience measures were captured using two validated surveys. The 15-item MR-anxiety questionnaire (MR-AQ) was administered immediately after the first treatment to rate MR-related anxiety and relaxation. The 40-item satisfaction with cancer care questionnaire rating doctors, radiation therapists, the services and care organization and their outpatient experience was administered immediately after the last treatment using five-point Likert responses. Results were analyzed using descriptive statistics. Results: 205 patients were included in this analysis. Multiple sites were treated across the pelvis and abdomen with a median treatment time per fraction of 46 and 66 min respectively. Patients rated MR-related anxiety as "not at all" (87%), "somewhat" (11%), "moderately" (1%) and "very much so" (1%). Positive satisfaction responses ranged from 78 to 100% (median 93%) across all items. All radiation therapist-specific items were rated positively as 96-100%. The five lowest rated items (range 78-85%) were related to general provision of information, coordination, and communication. Overall hospital care was rated positively at 99%. Conclusion: In this large, single-institution prospective cohort, all patients had low MR-related anxiety and completed treatment as planned despite lengthy ART treatments with the MR-linac. Patients overall were highly satisfied with their cancer care involving ART using an MR-linac.

Virtual follow-up care among breast and prostate cancer patients during and beyond the COVID-19 pandemic: Association with distress.

BACKGROUND: The purpose of this study was to investigate associations between self-reported distress (anxiety/depression) and satisfaction with and desire for virtual follow-up (VFU) care among cancer patients during and beyond the COVID-19 pandemic. METHODS: Breast and prostate cancer patients receiving VFU at an urban cancer centre in Toronto, Canada completed an online survey on their sociodemographic, clinical, and technology, characteristics and experience with and views on VFU. EQ5D-5 L was used to assess distress. Statistical models adjusted for age, gender, education, income and Internet confidence. RESULTS: Of 352 participants, average age was 65 years, 48% were women,79% were within 5 years of treatment completion, 84% had college/university education and 74% were confident Internet users. Nearly, all (98%) had a virtual visit via phone and 22% had a virtual visit via video. The majority of patients (86%) were satisfied with VFU and 70% agreed that they would like VFU options after the COVID-19 pandemic. Participants who reported distress and who were not confident using the Internet for health purposes were significantly less likely to be satisfied with VFU (OR = 0.4; 95% CI: 0.2-0.8 and OR = 0.19; 95% CI: 0.09-0.38, respectively) and were less likely to desire VFU option after the COVID-19 pandemic (OR = 0.49; 95% CI: 0.30-0.82 and OR = 0.41; 95% CI: 0.23-0.70, respectively). CONCLUSIONS: The majority of respondents were satisfied with VFU and would like VFU options after the COVID-19 pandemic. Future research should determine how to optimize VFU options for cancer patients who are distressed and who are less confident using virtual care technology.

Intraductal Prostate Cancer Affinity for Lymphatic-Predominant Metastases Through 18F-DCFPyL‒Prostate-Specific Membrane Antigen‒Positron Emission Tomography/CT Scans in Pretreatment Prostate Cancer Patients.

PURPOSE: Intraductal prostate cancer (IDC) is linked to unfavorable oncologic outcomes, marked by distinctive cellular intrinsic pathway changes and intricate immunosuppressive microenvironments that could impact the way cancer spreads. The aim of this study was to determine whether the presence of IDC in prostate biopsy specimens obtained from patients before primary prostate cancer (PCa) treatment is associated with a lymph node metastatic propensity in prostate-specific membrane antigen (PSMA)‒positron emission tomography (PET)/CT. MATERIALS AND METHODS: This was a cross-sectional analysis of all PCa patients undergoing a pretreatment 18F-DCFPyL-PSMA-PET/CT between January 1, 2016, and August 2021 at The Princess Margaret Cancer Centre. Outcomes were presence of any metastasis in the overall cohort, presence of lymphatic vs no metastases, and presence of lymphatic vs bone metastasis among patients who underwent PSMA-PET/CT as PCa primary staging. The associations between IDC presence on the prostate biopsy and the study outcomes were evaluated using univariable and multivariable logistic regression analyses. RESULTS: The cohort consisted of 120 patients. IDC and cribriform pattern were observed in 55 (46%) and 48 (40%) prostate biopsies, respectively. Overall, 52 patients (43%) had evidence of metastasis. Presence of IDC on biopsy was associated with increased odds of overall metastasis (odds ratio: 2.47, 95% CI: 1.09-5.61, P = .03). Of the 52 patients with evidence of metastasis, 41 (79%) had evidence of lymphatic metastasis. Presence of IDC on biopsy was associated with significantly increased odds of lymphatic metastasis vs nonmetastases (odds ratio: 3.03, 95% CI: 1.24-7.40, P = .01). CONCLUSIONS: The identification of IDC morphology in prostate biopsy specimens has been observed to be significantly linked with lymph node metastasis on 18F-DCFPyL-PET/CT imaging in a PCa pretreatment staging setting. We found that presence of IDC in prostate biopsy appears to be a marker for lymph node metastasis on 18F-DCFPyL-PET/CT.

Virtual Cancer Care Beyond the COVID-19 Pandemic: Patient and Staff Perspectives and Recommendations.

PURPOSE: COVID-19 catalyzed rapid implementation of virtual cancer care (VC); however, work is needed to inform long-term adoption. We evaluated patient and staff experiences with VC at a large urban, tertiary cancer center to inform recommendations for postpandemic sustainment. METHODS: All physicians who had provided VC during the pandemic and all patients who had a valid e-mail address on file and at least one visit to the Princess Margaret Cancer Centre in Toronto, Canada, in the preceding year were invited to complete a survey. Interviews and focus groups with patients and staff across the cancer center were analyzed using qualitative descriptive analysis and triangulated with survey findings. RESULTS: Response rates for patients and physicians were 15% (2,343 of 15,169) and 41% (100 of 246), respectively. A greater proportion of patients than physicians were satisfied with VC (80.1 v 53.4%; P < .01). In addition, fewer patients than physicians felt that virtual visits were worse than those conducted in person (28.0 v 43.4%; P < .01) and that telephone and video visits negatively affected the human interaction that they valued (59.8% v 82.0%; P < .01). Major barriers to VC for patients were respect for care preferences and personal boundaries, accessibility, and equitable access. For staff, major barriers included a lack of role clarity, dedicated resources (space and technology), integration of nursing and allied health, support (administrative, clinical, and technical), and guidance on appropriateness of use. CONCLUSION: Patient and staff perceptions and barriers to virtual care are different. Moving forward, we need to pay attention to both staff and patient experiences with virtual care since this will have major implications for long-term adoption into clinical practice.

Rate of pachymeningeal failure following adjuvant WBRT vs SRS in patients with brain metastases.

Background: Stereotactic radiosurgery (SRS) has supplanted whole brain radiotherapy (WBRT) as standard-of-care adjuvant treatment following surgery for brain metastasis (BrM). Concomitant with the adoption of adjuvant SRS, a new pattern of failure termed "Pachymeningeal failure" (PMF) has emerged. Methods: We reviewed a prospective registry of 264 BrM patients; 145 and 119 were treated adjuvantly with WBRT and SRS, respectively. The Cox proportional hazards model was used to identify variables correlating to outcomes. Outcomes were calculated using the cumulative incidence (CI) method. Univariate (UVA) and multivariate analyses (MVA) were done to identify factors associated with PMF. Results: CI of PMF was 2 % and 18 % at 12 months, and 2 % and 23 % at 24 months for WRBT and SRS, respectively (p < 0.001). The CI of classic leptomeningeal disease (LMD) was 3 % and 4 % at 12 months, and 6 % and 6 % at 24 months for WBRT and SRS, respectively (P = 0.67). On UVA, adjuvant SRS [HR 9.75 (3.43-27.68) (P < 0.001)]; preoperative dural contact (PDC) [HR 6.78 (1.64-28.10) (P = 0.008)]; GPA score [HR 1.64 (1.11-2.42) (P = 0.012)]; and lung EGFR/ALK status [HR 3.11 (1.02-9.45) (P = 0.045)]; were associated with PMF risk. On MVA, adjuvant SRS [HR 8.15 (2.69-24.7) (P < 0.001)]; and PDC [HR 6.28 (1.51-26.1) (P = 0.012)] remained associated with PMF. Conclusions: Preoperative dural contact and adjuvant SRS instead of adjuvant WBRT were associated with an increased risk of PMF. Strategies to improve pachymeningeal radiation coverage to sterilize at risk pachymeninges should be investigated.

Limitations of Prostate Biopsy in Detection of Cribriform and Intraductal Prostate Cancer.

BACKGROUND: The presence of cribriform morphology and intraductal carcinoma (IDC) in prostate biopsies and radical prostatectomy specimens is an adverse prognostic feature that can be used to guide treatment decisions. OBJECTIVE: To assess how accurately biopsies can detect cribriform morphology and IDC cancer by examining matched biopsy and prostatectomy samples. DESIGN, SETTING, AND PARTICIPANTS: Patients who underwent radical prostatectomy at The Princess Margaret Cancer Centre between January 2015 and December 2022 and had cribriform morphology and/or IDC in the surgical specimen were included in the study. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We used detection sensitivity to evaluate the level of agreement between biopsy and prostatectomy samples regarding the presence of cribriform morphology and IDC. RESULTS AND LIMITATIONS: Of the 287 men who underwent radical prostatectomy, 241 (84%) had cribriform morphology and 161 (56%) had IDC on final pathology. The sensitivity of prostate biopsy, using radical prostatectomy as the reference, was 42.4% (95% confidence interval [CI] 36-49%) for detection of cribriform morphology and 44.1% (95% CI 36-52%) for detection of IDC. The sensitivity of prostate biopsy for detection of either IDC or cribriform morphology was 52.5% (95% CI 47-58%). Among patients who underwent multiparametric magnetic resonance imaging-guided biopsies, the sensitivity was 54% (95% CI 39-68%) for detection of cribriform morphology and 37% (95% CI 19-58%) for detection of IDC. CONCLUSIONS: Biopsy has low sensitivity for detecting cribriform morphology and IDC. These limitations should be incorporated into clinical decision-making. Biomarkers for better detection of these histological patterns are needed. PATIENT SUMMARY: Prostate biopsy is not an accurate method for detecting two specific types of prostate cancer cells, called cribriform pattern and intraductal prostate cancer, which are associated with unfavorable prognosis.

Association of PSMA PET-derived Parameters and Outcomes of Patients Treated for Oligorecurrent Prostate Cancer.

Background Prostate-specific membrane antigen (PSMA) PET is useful in the early detection of oligorecurrent prostate cancer (PCa), but whether PSMA PET parameters can be used to identify patients who would benefit from metastasis-directed therapy (MDT) with radiation or surgery remains uncertain. Purpose To assess the association of PSMA PET parameters with outcomes of patients with oligorecurrent PCa after MDT. Materials and Methods In this retrospective analysis of a single-center phase II trial that enrolled patients with biochemical recurrence of PCa after maximal local therapy and with no evidence of disease at conventional imaging, patients underwent PSMA PET (between May 2017 and November 2021), and unveiled recurrences were treated with MDT. Maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean) and PSMA tumor volume derived using thresholds of 2.5 (SUVmean2.5) and 41% (SUVmean41%), respectively, were recorded for sites of recurrence on PSMA PET scans, and a molecular imaging PSMA score was assigned. These parameters were also corrected for smooth filter and partial volume effects, and the PSMA score was reassigned. Cox proportional hazards models were used to evaluate the relationship between PSMA PET parameters and outcomes. Results A total of 74 men (mean age, 68.3 years ± 6.6 [SD]) with biochemical recurrence of PCa were included. PSMA PET revealed 145 lesions in the entire cohort, of which 125 (86%) were metastatic lymph nodes. Application of the correction factor changed the PSMA score in 88 of 145 lesions (61%). Mean SUVmax, SUVmean2.5, and SUVmean41% were associated with lower risk of biochemical progression (hazard ratio [HR] range, 0.77-0.95; 95% CI: 0.61, 1.00; P = .03 to P = .04). For corrected parameters, mean SUVmax, mean SUVmean2.5, mean SUVmean41%, mean PSMA score, maximum SUVmean2.5, maximum SUVmean41%, and maximum PSMA score were associated with a lower risk of biochemical progression (HR, 0.61-0.98; 95% CI: 0.39, 1.00; P = .01 to P = .04). Conclusion Measured and corrected PSMA PET parameters were associated with biochemical progression in men with oligorecurrent PCa treated with MDT. Clinical trial registration no. NCT03160794 © RSNA, 2023 See also the editorial by Civelek in this issue.

A qualitative study on healthcare professional and patient perspectives on nurse-led virtual prostate cancer survivorship care.

BACKGROUND: Virtual nurse-led care models designed with health care professionals (HCPs) and patients may support addressing unmet prostate cancer (PCa) survivor needs. Within this context, we aimed to better understand the optimal design of a service model for a proposed nurse-led PCa follow-up care platform (Ned Nurse). METHODS: A qualitative descriptive study exploring follow-up and virtual care experiences to inform a nurse-led virtual clinic (Ned Nurse) with an a priori convenience sample of 10 HCPs and 10 patients. We provide a health ecosystem readiness checklist mapping facilitators onto CFIR and Proctor's implementation outcomes. RESULTS: We show that barriers within the current standard of care include: fragmented follow-up, patient uncertainty, and long, persisting wait times despite telemedicine modalities. Participants indicate that a nurse-led clinic should be scoped to coordinate care and support patient self-management, with digital literacy considerations. CONCLUSION: A nurse-led follow-up care model for PCa is seen by HCPs as acceptable, feasible, and appropriate for care delivery. Patients value its potential to provide role clarity, reinforce continuity of care, enhance mental health support, and increase access to timely and targeted care. These findings inform design, development, and implementation strategies for digital health interventions within complex settings, revealing opportunities to optimally situate these interventions to improve care.

Prostate cancer (PCa) survivors in Canada receive follow-up care after treatment through a specialist-led model, which is currently straining to meet patient needs. We interviewed healthcare providers (HCPs) and patients to investigate the design and development of a healthcare service that uses technology, also known as virtual care, to provide nurse-led follow-up care. Mixed experiences with virtual care informed participant feedback and concerns, including impacts of the pandemic and digital literacy considerations. We show that HCPs and patients see potential benefit in virtual nurse-led follow-up care if it can increase access to resources, clarify patient and provider care roles, and improve access and continuity of care. This type of approach to follow-up care may help to improve survivor quality of life and PCa follow-up care while extending the reach of healthcare systems with limited resources.

Use of focal radiotherapy boost for prostate cancer: radiation oncologists' perspectives and perceived barriers to implementation.

BACKGROUND: In a recent phase III randomized control trial, delivering a focal radiotherapy (RT) boost to tumors visible on MRI was shown to improve disease-free survival and regional/distant metastasis-free survival for patients with prostate cancer-without increasing toxicity. The aim of this study was to assess how widely this technique is being applied in current practice, as well as physicians' perceived barriers toward its implementation. METHODS: We invited radiation oncologists to complete an online questionnaire assessing their use of intraprostatic focal boost in December 2022 and February 2023. To include perspectives from a broad range of practice settings, the invitation was distributed to radiation oncologists worldwide via email list, group text platform, and social media. RESULTS: 263 radiation oncologist participants responded. The highest-represented countries were the United States (42%), Mexico (13%), and the United Kingdom (8%). The majority of participants worked at an academic medical center (52%) and considered their practice to be at least partially genitourinary (GU)-subspecialized (74%). Overall, 43% of participants reported routinely using intraprostatic focal boost. Complete GU-subspecialists were more likely to implement focal boost, with 61% reporting routine use. In both high-income and low-to-middle-income countries, less than half of participants routinely use focal boost. The most cited barriers were concerns about registration accuracy between MRI and CT (37%), concerns about risk of additional toxicity (35%), and challenges to accessing high-quality MRI (29%). CONCLUSIONS: Two years following publication of a randomized trial of patient benefit without increased toxicity, almost half of the radiation oncologists surveyed are now routinely offering focal RT boost. Further adoption of this technique might be aided by increased access to high-quality MRI, better registration algorithms of MRI to CT simulation images, physician education on benefit-to-harm ratio, and training on contouring prostate lesions on MRI.

A feasibility study of adaptive radiation therapy for postprostatectomy prostate cancer.

Postoperative prostate radiotherapy requires large planning target volume (PTV) margins to account for motion and deformation of the prostate bed. Adaptive radiation therapy (ART) can incorporate image-guidance data to personalize PTVs that maintain coverage while reducing toxicity. We present feasibility and dosimetry results of a prospective study of postprostatectomy ART. Twenty-one patients were treated with single-adaptation ART. Conventional treatments were delivered for fractions 1 to 6 and adapted plans for the remaining 27 fractions. Clinical target volumes (CTVs) and small bowel delineated on fraction 1 to 4 CBCT were used to generate adapted PTVs and planning organ-at-risk (OAR) volumes for adapted plans. PTV volume and OAR dose were compared between ART and conventional using Wilcoxon signed-rank tests. Weekly CBCT were used to assess the fraction of CTV covered by PTV, CTV D99, and small bowel D1cc. Clinical metrics were compared using a Student's t-test (p < 0.05 significant). Offline adaptive planning required 1.9 ± 0.4 days (mean ± SD). ART decreased mean adapted PTV volume 61 ± 37 cc and bladder wall D50 compared with conventional treatment (p < 0.01). The CTV was fully covered for 96% (97%) of fractions with ART (conventional). Reconstructing dose on weekly CBCT, a nonsignificant reduction in CTV D99 was observed with ART (94%) compared to conventional (96%). Reduced CTV D99 with ART was significantly correlated with large anterior-posterior rectal diameter on simulation CT. ART reduced the number of fractions exceeding our institution's small bowel D1c limit from 14% to 7%. This study has demonstrated the feasibility of offline ART for post-prostatectomy cancer. ART facilitates PTV volume reduction while maintaining reasonable CTV coverage and can reduce the dose to adjacent normal tissues.