PSMA PET/CT for Response Assessment and Overall Survival Prediction in Patients with Metastatic Castration-Resistant Prostate Cancer Treated with Androgen Receptor Pathway Inhibitors.

We aimed to evaluate the role of prostate-specific membrane antigen (PSMA) PET/CT for response assessment and outcome prediction in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with androgen receptor pathway inhibitors (ARPIs), including abiraterone acetate or enzalutamide. Methods: We retrospectively analyzed 30 ARPI-treated mCRPC patients who underwent 68Ga-PSMA-11 PET/CT within 8 wk before (baseline) and 12 ± 4 wk after treatment initiation. Total PSMA tumor volume was calculated using the fixed threshold method (SUV ≥ 3). Patients were categorized as PSMA responders (PSMA-Rs) or PSMA nonresponders (PSMA-NRs) on the basis of both European Association of Urology/European Association of Nuclear Medicine (EAU/EANM) criteria and Response Evaluation Criteria in PSMA PET/CT (RECIP) 1.0. PSMA-R included patients with a complete response, a partial response, or stable disease, and PSMA-NR included those with progressive disease. On the basis of prostate-specific antigen (PSA), patients were classified as biochemical responders if PSA decreased by at least 50% and as nonresponders if it did not. The Φ-coefficient was used to evaluate the correlation of PSMA- and PSA-based responses. Survival analysis was performed using the Cox regression hazard model and the Kaplan-Meier method. Predictive accuracy was tested for both response criteria. Results: On the basis of PSMA PET/CT, 13 (43%) patients were PSMA-NR according to the EAU/EANM criteria and 11 (37%) patients were PSMA-NR according to RECIP 1.0. Significant correlations were observed between PSMA- and PSA-based responses for both criteria (Φ = 0.79 and 0.66, respectively). After a median follow-up of 25 mo (interquartile range, 21-43 mo), the median overall survival was significantly longer for PSMA-R than PSMA-NR (54 vs. 22 mo) for both the EAU/EANM criteria and RECIP 1.0, with hazard ratios of 6.9 (95% CI, 1.9-26; P = 0.004) and 5.6 (95% CI, 1.69-18.26, P = 0.005), respectively. No significant difference in predictive accuracy was found between the 2 criteria (C-index, 0.79 vs. 0.76, respectively, P = 0.54). Flare phenomena at the second PSMA PET study were not observed in our cohort. Conclusion: Our results demonstrate that PSMA PET/CT is a valuable imaging biomarker for response assessment and overall survival prediction when performed at 3 mo after ARPI treatment initiation in mCRPC patients. Both proposed PSMA response criteria (EAU/EANM and RECIP 1.0) seem to perform equally well. No PSMA flare was observed. Prospective validation of these findings is strongly needed.

Development, multi-institutional external validation, and algorithmic audit of an artificial intelligence-based Side-specific Extra-Prostatic Extension Risk Assessment tool (SEPERA) for patients undergoing radical prostatectomy: a retrospective cohort study.

BACKGROUND: Accurate prediction of side-specific extraprostatic extension (ssEPE) is essential for performing nerve-sparing surgery to mitigate treatment-related side-effects such as impotence and incontinence in patients with localised prostate cancer. Artificial intelligence (AI) might provide robust and personalised ssEPE predictions to better inform nerve-sparing strategy during radical prostatectomy. We aimed to develop, externally validate, and perform an algorithmic audit of an AI-based Side-specific Extra-Prostatic Extension Risk Assessment tool (SEPERA). METHODS: Each prostatic lobe was treated as an individual case such that each patient contributed two cases to the overall cohort. SEPERA was trained on 1022 cases from a community hospital network (Trillium Health Partners; Mississauga, ON, Canada) between 2010 and 2020. Subsequently, SEPERA was externally validated on 3914 cases across three academic centres: Princess Margaret Cancer Centre (Toronto, ON, Canada) from 2008 to 2020; L'Institut Mutualiste Montsouris (Paris, France) from 2010 to 2020; and Jules Bordet Institute (Brussels, Belgium) from 2015 to 2020. Model performance was characterised by area under the receiver operating characteristic curve (AUROC), area under the precision recall curve (AUPRC), calibration, and net benefit. SEPERA was compared against contemporary nomograms (ie, Sayyid nomogram, Soeterik nomogram [non-MRI and MRI]), as well as a separate logistic regression model using the same variables included in SEPERA. An algorithmic audit was performed to assess model bias and identify common patient characteristics among predictive errors. FINDINGS: Overall, 2468 patients comprising 4936 cases (ie, prostatic lobes) were included in this study. SEPERA was well calibrated and had the best performance across all validation cohorts (pooled AUROC of 0·77 [95% CI 0·75-0·78] and pooled AUPRC of 0·61 [0·58-0·63]). In patients with pathological ssEPE despite benign ipsilateral biopsies, SEPERA correctly predicted ssEPE in 72 (68%) of 106 cases compared with the other models (47 [44%] in the logistic regression model, none in the Sayyid model, 13 [12%] in the Soeterik non-MRI model, and five [5%] in the Soeterik MRI model). SEPERA had higher net benefit than the other models to predict ssEPE, enabling more patients to safely undergo nerve-sparing. In the algorithmic audit, no evidence of model bias was observed, with no significant difference in AUROC when stratified by race, biopsy year, age, biopsy type (systematic only vs systematic and MRI-targeted biopsy), biopsy location (academic vs community), and D'Amico risk group. According to the audit, the most common errors were false positives, particularly for older patients with high-risk disease. No aggressive tumours (ie, grade >2 or high-risk disease) were found among false negatives. INTERPRETATION: We demonstrated the accuracy, safety, and generalisability of using SEPERA to personalise nerve-sparing approaches during radical prostatectomy. FUNDING: None.

Cost-analysis of robot-assisted radical cystectomy in Europe: A cross-country comparison.

BACKGROUND: Robotic-assisted radical cystectomy (RARC) with intracorporeal urinary diversion (ICUD) is surging worldwide. Aim of the study was to perform a multicentric cost-analysis of RARC by comparing the gross cost of the intervention across hospitals in four different European countries. METHODS: Patients who underwent RARC + ICUD were recruited from eleven European centers in four European countries (Belgium, France, Netherlands, and UK) between 2015 and 2020. Costs were divided into six parts: cost for hospital stay, cost for ICU stay, cost for surgical theater occupation, cost for transfusion, cost for robotic instruments, and cost for stapling instruments. These costs were individually assessed for each patient. RESULTS: A total of 490 patients were included. Median operative time was 300(270-360) minutes and median hospital length-of-stay was 11(8-15) days. The average total cost of RARC was 14.794€ (95%CI 14.300-15.200€). A significant difference was found for the total cost, as well as the various subcosts abovementioned, between the four included countries. Different sets and types of robotic instruments were used by each center, leading to a difference in cost of robotic instrumentation. Nearly 84% of costs of RARC were due to hospital stay (42%), ICU stay (3%) and operative time (39%), while 16% of costs were due to robotic (8%) and stapling (8%) instruments. CONCLUSION: Costs and subcosts of RARC + ICUD vary significantly across European countries and are mainly dependent of hospital length-of-stay and operative time rather than robotic instrumentation. Decreasing length-of-stay and reducing operative time could help to decrease the cost of RARC and make it more widely accessible.

68Ga-PSMA PET/CT for Response Assessment and Outcome Prediction in Metastatic Prostate Cancer Patients Treated with Taxane-Based Chemotherapy.

We aimed to evaluate the role of PET targeting the prostate-specific membrane antigen (PSMA) for response assessment in metastatic prostate cancer (PCa) patients treated with taxane-based chemotherapy (docetaxel or cabazitaxel) and its predictive value on patient outcome. Methods: We retrospectively evaluated 37 patients with metastatic hormone-sensitive PCa or metastatic castration-resistant PCa (mCRPC) who underwent 68Ga-PSMA-11 PET/CT at baseline and after the last cycle of taxane-based chemotherapy (docetaxel or cabazitaxel) without treatment modification between scans. Biochemical response (BR) was defined as an undetectable or at least 50% decreased level of prostate-specific antigen, compared with baseline. Associations between BR and different PET parameters were tested. A cutoff of at least a 30% decrease in PSMA total tumor volume (PSMA-TV) was used to define a PSMA response (PSMA-R) versus a PSMA nonresponse (PSMA-NR). Correlations between PSMA PET/CT response and BR were evaluated using the ϕ-coefficient. Associations between PET response and overall survival (OS) was tested using Cox regression and the Kaplan-Meier method. Results: Our cohort comprised 8 (22%) metastatic hormone-sensitive PCa and 29 (78%) mCRPC patients. Twenty-one patients received docetaxel treatment, and 16 received cabazitaxel (median, 6 cycles; interquartile range, 5-8 cycles). BR was found in 18 of 37 patients. Using PSMA total tumor volume, PSMA PET/CT response was concordant with BR in 35 of 37 patients (ϕ = 0.89, P < 0.0001). Eighteen of 37 patients had PSMA-R (6, complete response; 12, partial response), and 19 had PSMA-NR (17, progressive disease; 2, stable disease). After a median follow-up of 23 mo, there was a statistically significant longer OS for PSMA-R than for PSMA-NR (median OS not reached vs. 12 mo, respectively; hazard ratio, 0.10; 95% CI, 0.03-0.39; P = 0.001) for the entire population. Among the mCRPC subgroup, differences in OS were also observed (median, 22 vs. 12 mo, respectively; hazard ratio, 0.22; 95% CI, 0.06-0.82; P = 0.023), with a 12-mo OS rate of 100% for PSMA-R and 52% for PSMA-NR (P = 0.011). Conclusion: This retrospective analysis suggests that 68Ga-PSMA-11 PET/CT is a promising imaging modality for assessing response to taxane-based chemotherapy in metastatic PCa. Changes in PSMA expression might be used as a predictive biomarker for OS to help tailor individual therapy and select eligible patients for clinical trials.

Validated Prospective Assessment of Quality of Life After Robot-Assisted Laparoscopic Prostatectomy: Beyond Continence and Erections.

Continence and erectile function represent major concerns after robot-assisted laparoscopic prostatectomy (RALP), although the analysis of only these results may underestimate the impact of surgery on quality of life (QoL). The aim of the study is to prospectively analyze QoL after RALP according to the validated European Organization for Research and Treatment of Cancer Quality of Life Questionnaire prostate cancer-specific module (EORTC-QLQ-PR25) and C30 and explore risk factors for the deterioration of QoL after surgery. A total of 584 patients undergoing RALP were prospectively enrolled. QoL was assessed with the validated EORTC-QLQ-PR25 and C30. Differences across QoL items were assessed via Wilcoxon rank-sum test and associations between risk factors and QoL scores were tested via univariate and multivariate linear regression analyses. All items of the PR25 questionnaire showed a significant deterioration at 1 month after RALP and began to normalize 3 months after surgery. At 24 months follow-up, urinary, bowel, and sexual activity scores were not significantly different from preoperative scores, while incontinence aid, treatment-related symptoms, and sexual functioning remained significantly worse. Preoperative sexual activity was more important in determining 3-month sexual outcomes than preoperative 5-item version of the International Index of Erectile Function (IIEF-5) or nerve-sparing approach. An overall return to preoperative QoL was registered at 3 months after RALP in global and physical QoL, and most important, global, physical, social, and role-functioning QoL scores were improved at 12 and 24 months compared to preoperative scores. In this prospective study, detailed data on QoL are reported via the EORTC-PR25 and C30 questionnaires. While urinary, bowel, and sexual activity scores return to baseline values 24 months after surgery, incontinence aid, treatment-related symptoms, and sexual functioning may remain significantly deteriorated. Larger studies are needed to validate these findings.