Citations

Abstract Background: Many patients use artificial intelligence (AI) chatbots as a rapid source of health information. This raises important questions about the reliability and effectiveness of AI chatbots in delivering accurate and understandable information. Purpose: To evaluate and compare the accuracy, conciseness, and readability of responses from OpenAI ChatGPT-4 and Google Bard to patient inquiries concerning the novel 177Lu-PSMA-617 therapy for prostate cancer. Materials and Methods: Two experts listed the 12 most commonly asked questions by patients on 177Lu-PSMA-617 therapy. These twelve questions were prompted to OpenAI ChatGPT-4 and Google Bard. AI-generated responses were distributed using an online survey platform (Qualtrics) and blindly rated by eight experts. The performances of the AI chatbots were evaluated and compared across three domains: accuracy, conciseness, and readability. Additionally, potential safety concerns associated with AI-generated answers were also examined. The Mann-Whitney U and chi-square tests were utilized to compare the performances of AI chatbots. Results: Eight experts participated in the survey, evaluating 12 AI-generated responses across the three domains of accuracy, conciseness, and readability, resulting in 96 assessments (12 responses x 8 experts) for each domain per chatbot. ChatGPT-4 provided more accurate answers than Bard (2.95 ± 0.671 vs 2.73 ± 0.732, p=0.027). Bard's responses had better readability than ChatGPT-4 (2.79 ± 0.408 vs 2.94 ± 0.243, p=0.003). Both ChatGPT-4 and Bard achieved comparable conciseness scores (3.14 ± 0.659 vs 3.11 ± 0.679, p=0.798). Experts categorized the AI-generated responses as incorrect or partially correct at a rate of 16.6% for ChatGPT-4 and 29.1% for Bard. Bard's answers contained significantly more misleading information than those of ChatGPT-4 (p = 0.039). Conclusion: AI chatbots have gained significant attention, and their performance is continuously improving. Nonetheless, these technologies still need further improvements to be considered reliable and credible sources for patients seeking medical information on 177Lu-PSMA-617 therapy.

AbstractBackgroundProstate cancer (PCa) parenchymal brain metastases are uncommon and troubling observations in the course of the disease. Our study aims to evaluate the prevalence of brain metastases among PCa patients while reporting various therapeutic modalities, clinical features, and oncological outcomes.MethodsWe retrospectively identified 34 patients with parenchymal brain metastasis out of 4575 patients using a prospectively maintained database that contains clinicopathologic characteristics of PCa patients between January 2012 and December 2021. Based on the three treatment modalities used, the patients were divided into three groups: stereotactic radiosurgery (SRS), whole brain radiotherapy (WBRT), and systemic therapy alone. The Kaplan–Meier curve was used to calculate overall survival [OS] probability and the Cox proportional hazards regression model was used to compare between groups.ResultsAt the time of brain metastasis diagnosis, the median age was 66 years, the median (interquartile range [IQR]) prostate‐specific antigen (PSA) was 2.2 (0.1–26.6) ng/ml and the median (IQR) months from initial PCa diagnosis to brain metastasis development was 70.8 (27.6–100.9). The median (IQR) primary Gleason score was 8 (7–9) and over a median (IQR) follow‐up time of 2.2 (1.2–16.5) months, 76.5% (n = 26) of the patients died. Thirteen (38.2%) patients had solitary lesion, whereas 21 (61.8%) had ≥2 lesions. The lesions were supratentorial in 19 (55.9%) patients, infratentorial in six (17.6%), and both sides in nine (26.5%). Among all 34 patients, 10 (29.4%) were treated with SRS, seven (20.6%) with WBRT, and 17 (50%) with systemic therapy alone. OS varied greatly between the three treatment modalities (log‐rank test, p = 0.049). Those who were treated with SRS and WBRT had better OS compared with patients who were treated with systemic therapy alone (hazard ratio: 0.37, 95% confidence interval: 0.16–0.86, p = 0.022).ConclusionsIn our single‐institutional study, we confirmed that PCa brain metastasis is associated with poor survival outcomes and more advanced metastatic disease. Furthermore, we found that SRS and WBRT for brain metastasis in patients with recurrent PCa appear to be associated with improved OS as compared with systemic therapy alone and are likely secondary to selection bias.

AbstractBackgroundFor men with prostate cancer, radiographic progression may occur without a concordant rise in prostate‐specific antigen (PSA). Our study aimed to assess the prevalence of radiographic progression using C‐11 choline positron emission tomography (PET) imaging in patients achieving ultra‐low PSA values and to evaluate clinical outcomes in this patient population.MethodsIn a single institution study, we reviewed the prospectively maintained Mayo Clinic C‐11 Choline PET metastatic prostate cancer registry to identify patients experiencing radiographic disease progression (rDP) on C‐11 choline PET scan while the PSA value was less than 0.5 ng/mL. Disease progression was confirmed by tissue biopsy or response to subsequent therapy. Clinicopathologic variables were abstracted by trained research personnel. Overall survival was estimated using the Kaplan–Meier method. Intergroup differences were assessed using the log‐rank test. A univariate and multivariate Cox regression model was performed to investigate variables associated with poor survival after rDP.ResultsA total of 1323 patients within the registry experienced rDP between 2011 and 2021, including 220 (16.6%) men with rDP occurring at low PSA level. A median (interquartile range [IQR]) of 54.7 (19.7–106.9) months elapsed between the time of prostate cancer diagnosis and low PSA rDP, during which 173 patients (78%) developed castration‐resistant prostate cancer (CRPC). Sites of low PSA rDP included local recurrence (n = 17, 8%), lymph node (n = 90, 41%), bone (n = 94, 43%) and visceral metastases (n = 19, 9%). Biopsy at the time of rDP demonstrated small‐cell or neuroendocrine features in 21% of patients with available tissue. Over a median (IQR) follow‐up of 49.4 (21.3–95.1) months from the time of low PSA rDP, 46% (n = 102) of patients died. Factors associated with poorer survival outcomes include advanced age at rDP, CRPC status, bone and visceral metastasis (p value <0.05). Visceral metastases were associated with decreased overall survival (p = 0.009 by log‐rank) as compared with other sites of rDP.ConclusionsMen with prostate cancer commonly experience metastatic progression at very low or even undetectable PSA levels. Periodic imaging, even at low absolute PSA values, may result in more timely identification of disease progression.

Introduction: As interest in metastasis-directed therapy (MDT) for prostate cancer (PCa) grows, exploring indications and patient selection is increasingly more important. Thus far, few studies have described long-term outcomes after surgical MDT in those with disease recurrence involving the lung. The objective of our study was to compare the cumulative incidence of cancer-related death by treatment modality in men with metachronous pulmonary metastases from PCa. Methods: In a single-institution retrospective study, we identified 75 men from the prospectively maintained Mayo Clinic C-11 Positron Emission Tomography Choline PCa registry with recurrent prostate cancer involving the lung but no other visceral organs. Patients were categorized into 3 groups based on treatment modalities: wedge resection ± hormonal therapy, chemohormonal therapy, and hormonal therapy alone. The risk of cancer-related death after treatment at the time of lung metastases was reported as cumulative incidence estimates. Non–cancer-related deaths were treated as a competing risk of death. A univariate Cox regression model was conducted to assess the impact of treatment modality on the risk of cancer-related death. Results: At the time of lung metastasis, the median age was 69.5 years, and the median (IQR) prostate-specific antigen was 4 (1.3-8.6) ng/ml. Forty-seven patients (62.7%) had hormone-sensitive disease, and 28 patients (37.3%) had hormone-resistant disease. A total of 26 patients (34.7%) were treated with wedge resection ± hormonal therapy, 27 (36%) with chemohormonal therapy, and 22 (29.3%) with hormonal therapy alone. The median (IQR) follow-up time was 50.3 (31.1-78.4) months, and 21 patients (28%) died. Patients who were treated with wedge resection ± hormonal therapy had lower rated of cancer-related death compared with those who received chemohormonal therapy (Hazard Ratio [HR]: 4.14, 95% CI: 1.01-16.96, P = .048) or hormonal therapy alone (HR: 6.37, 95% CI: 1.72-23.54, P = .005). Conclusion: This exploratory analysis supports the safety and feasibility of surgical metastasis-directed therapy in select patients with recurrent prostate cancer involving the lung. Favorable long-term survival provides justification for further evaluation of this approach.

Abstract Background The efficacy of pembrolizumab monotherapy in metastatic castration-resistant prostate cancer patients when stratified by MSI-H and/or TMB-H is poorly defined. Additionally, outcomes based on sequencing source (i.e., tissue or liquid biopsy) have not been well described. We sought to assess outcomes of pembrolizumab monotherapy in patients with mCRPC and compare efficacy based on MSI-H and/or TMB-H when identified by tissue or liquid biopsy. Methods A retrospective analysis was performed of mCRPC patients treated at Mayo Clinic with pembrolizumab monotherapy between 2018 and 2023. Objective response rates (ORR), median progression-free survival (mPFS), and overall survival (mOS), were determined by RECIST v1.1 criteria. Results Twenty-two patients with mCRPC received pembrolizumab monotherapy for at least 3 cycles for an MSI-H or TMB-H indication. All patients had next generation sequencing (NGS) performed via tissue (n = 11) or liquid (n = 10) biopsy source. The ORR was 50% (27.3% complete response and 22.7% had partial response). The mPFS for TMB 10-14.9 mut/Mb (n = 4), TMB 15-24.9 mut/Mb (n = 6), and TMB ≥ 25 mut/Mb (n = 10) was 2.1, not reached (NR), and NR, respectively (p = 0.0003). The mOS for these same groups was 5.1 months, 20.5 months, and not reached, respectively. Among patients with TMB-H without co-occurring MSI-H or CDK12 (n = 6), none experienced a response and only one patient had stable disease compared to patients with MSI-H (n = 12) for whom the ORR was 75%. Immunotherapy responsive alterations such as ATRX and PTCH1 mutations were frequently noticed among patients who had complete response (CR). Conclusions Our study highlights that MSI-H drives the efficacy of pembrolizumab in mCRPC with better survival outcomes as TMB increases. Clinicians should consider alternative treatment strategies for advanced prostate cancer when TMB-H is present without co-occurring MSI-H or CDK12. This study further demonstrates the utility of liquid biopsy NGS for identifying MSI-H and/or TMB-H disease.

e17057 Background: Results from the VISION trial (NCT03511664) led to the approval of lutetium-177 (177Lu)–PSMA-617 for the treatment of metastatic castration-resistant prostate cancer (mCRPC). This trial excluded patients with baseline cytopenias, thus safety in this frequently encountered patient population is unknown. We aimed to use real-world data to describe the tolerability of radioligand therapy in those with poorer bone marrow reserve. Methods: We retrospectively reviewed the records of all patients, who received a first dose of 177Lu–PSMA-617 at Mayo Clinic in the interval of April 26, 2022, to December 1, 2022. Patients were categorized as having poor marrow reserve on the basis of pre-treatment hematologic parameters, including: (1) an anemia cohort with hemoglobin (Hg) less than 9 g/dL, (2) a thrombocytopenia cohort with platelets (Plt) less than 100 x 109/L, (3) a leukopenia cohort with white blood cell count (WBC) less than 2.5 x 109/L, and (4) a multiple cytopenia cohort. These were exclusionary parameters from the VISION trial. Longitudinal laboratory data and clinical outcomes were collected and analyzed using descriptive statistics. Results: At data cutoff, 185 patients had received one or more doses of 177Lu, including 26 (14%) with at least one baseline cytopenia prior to their first cycle of treatment. In total, there were 19 (73%) patients with anemia, 3 (12%) with thrombocytopenia, 2 (8%) with leukopenia, and 2 (8%) with multiple cytopenias at baseline. The median number of cycles received thus far is 3, including 14 (54%) who are still receiving therapy and 12 (46%) who have permanently discontinued treatment. Median longitudinal changes in blood counts for the anemia cohort are presented in Table 1. Reasons for treatment discontinuation include: toxicity (n = 2), disease progression (n = 5), death (n = 4), or other (n = 1). Dose reductions or treatment delays for worsening myelosuppression were utilized in 3 (12%) and 5 (19%) patients, respectively. Transfusions of packed red blood cells or platelets were required for 16 (62%) patients. A total of 6 (23%) received care in the emergency department or were hospitalized. Conclusions: Treatment discontinuation for toxicity was rare among men with mCRPC and baseline cytopenias, while receiving 177Lu; however, these patients have an overall poor prognosis. [Table: see text]

5088 Background: Previous evidence suggests that there may be no additional benefit of triplet therapy in low volume disease based on limited data. Therefore, we investigated the efficacy of triplet therapy as compared to docetaxel (D) and androgen pathway inhibitor (API) doublets by volume of disease using the most up to date results from the ARASENS trial. Methods: Phase III randomized controlled trials (RCTs) assessing treatment intensification with API, and/or D in patients with mCSPC were included. Precomputed hazard ratios (HR) with 95% confidence intervals (CI) for OS were pooled using an inverse-variance approach. A DerSimonian-Laird random-effects meta-analysis was conducted to assess the efficacy of triplet therapy compared to D doublet therapy. P-value of interaction was computed to assess difference between high (HV) and low volume (LV) disease subgroups (Pint <0.1 - statistical significance). Additionally mixed treatment comparisons were computed using network meta-analysis (NMA) to assess the comparative effectiveness of triplet therapy compared to API doublets by volume of disease. Results: Pairwise meta-analysis included a total of 3 RCTs (ARASENS, PEACE-1, ENZAMET) with 2518 patients (HV: 1820; LV: 698) as shown. In patients with HV disease, 385 (43%) and 484 (53%) deaths were observed with triplet therapy, and D doublet, respectively. Triplet therapy significantly improved OS as compared to D doublet in HV (HR: 0.73; 95% CI: 0.64-0.84). In patients with LV disease, 73 (20%) and 94 (28%) deaths were observed with triplet therapy, and D doublet, respectively. Triplet therapy significantly improved OS as compared to D doublet in LV (HR: 0.71; 95% CI: 0.52-0.97). There was no statistically significant interaction by volume of disease for triplet therapy vs. D doublet (Pint: 0.86). NMA including 10 clinical trials and over 11500 patients updated as of 13th Feb 2023 showed that in HV mCSPC, triplet therapy was ranked as potentially the most efficacious treatment option and may improve OS compared to API doublet therapy (HR: 0.83; 95% CI: 0.66-1.03). In LV mCSPC, API doublet therapy was ranked as potentially the most efficacious treatment followed by triplet therapy. There was no significant difference between triplet therapy and API doublet therapy (HR: 1.12; 95% CI: 0.74-1.12). Conclusions: These results underscore that triplet therapy may be preferred in mCSPC patients with HV disease whereas API doublet therapy may be preferred in LV disease. [Table: see text]

Abstract Background The objective of this study was to evaluate the prognostic value of early PSA decline following initiation of second-generation hormone therapy (2nd HT), namely abiraterone acetate or enzalutamide, in patients with taxane-refractory metastatic castrate-resistant prostate cancer (mCRPC) and evaluate utility of this metric in informing intensified surveillance/imaging protocols. Methods We retrospectively identified 75 mCRPC patients treated with 2nd HT following docetaxel failure (defined as PSA rise and radiographic progression). Patients were categorized patients into two cohorts based on the first PSA within 3 months after initiation of therapy: PSA reduction ≥ 50% (Group A) and PSA reduction < 50% (Group B). The primary endpoint was cancer-specific mortality (CSM). The secondary endpoint was radiographic disease progression (rDP) on 2nd HT. In univariate and multivariate analyses, we investigated factors associated with rPD and CSM. Results We included 75 patients (52 in Group A, 23 in Group B) in the analytic cohort. Baseline clinico-demographic characteristics, including median age, primary Gleason score risk group, median pre-treatment PSA, disease burden, site of metastases, and pre-treatment ECOG score were not statistically different between the two groups. Median follow up time was 30 months and the median time to radiographic disease progression was 28.1 and 12.5 months (p = 0.002) in cohorts A and B, respectively. On univariate and multivariate analyses, both PSA reduction ≥ 50% and volume of metastatic disease were significantly associated with a decreased risk of radiographic disease progression (HR 0.41, 95% CI 0.21–0.80, p = 0.0113) as well as a decreased risk of cancer-specific mortality (HR 0.29, 95% CI 0.09–0.87, p = 0.0325). Conclusion PSA reduction ≥ 50% within 3 months of starting 2nd HT was associated with significantly improved radiographic disease progression-free survival and 3-year cancer-specific mortality. This suggests using PSA 50%-decline metric in surveillance patients with on 2nd HT and identifies patients who require further evaluation with imaging.

60 Background: Recent studies, including a post-hoc analysis of the ARCHES trial, highlight radiographic disease progression (rDP) occurring without concordant rise in prostate specific antigen (PSA). In a previous study by our group, we reported that almost 40% of patients on 2nd generation hormone therapy experience rDP with non-rising PSA and have poor survival outcomes. The current analysis more specifically focuses on the subgroup of patients with rDP occurring at low PSA (<0.5 ng/dL) and describes factors associated with poorer survival outcomes in this patient population. Methods: In a single institution study, we reviewed the prospectively maintained Mayo Clinic C-11 Choline PET registry for patients treated between 2011 and 2021, who experienced rDP at low PSA (value < 0.5 ng/mL). Disease progression on C-11 choline PET was confirmed by either tissue biopsy or subsequent response to therapy. We investigated factors associated with poor cancer-specific survival outcomes in univariable and multivariable cox regression analyses. Results: In total, 220 (16%) patients experiencing rDP at low PSA were identified. Median (IQR) age at rDP was 67.91 (61.10 – 73.87) yrs., median (IQR) primary Gleason score was 9 (7-9), and median (IQR) PSA was 0.17 (0 – 0.32) ng/ml. 75% of the patients (n=166) had CRPC disease status at time of rDP. Prior systemic treatments included 2nd generation HT in 18% (n= 40) and chemotherapy in 31% (n=70). Sites of rDP were divided into 7% local (n=16), 42% lymph nodes (n=91), 43% bone (n=95), and 8% visceral metastases (n=18). Over a median follow-up duration of 55 months, 46% of patients (n=100) reported death. Factors associated with poor survival outcomes are demonstrated in the table and include age at rDP, CRPC status, and disease location (P-value <0.05). Conclusions: We found that radiographic disease progression commonly occurs at low PSA (<0.5 ng/mL). CRPC-disease status and the development of visceral metastases are associated with particularly poor survival outcomes. To identify early progression, monitoring with imaging may be warranted, even in the patients with low PSA. [Table: see text]