Metformin for patients with metastatic prostate cancer starting androgen deprivation therapy: a randomised phase 3 trial of the STAMPEDE platform protocol

Background Metformin is a widely used anti-diabetic drug. Several studies have suggested that metformin has anticancer activity in some malignancies, including prostate cancer. Metformin might also mitigate the adverse metabolic effects of androgen-deprivation therapy (ADT). We hypothesised that metformin might improve survival in patients with metastatic hormone-sensitive prostate cancer and reduce metabolic complications associated with ADT. Methods The STAMPEDE multi-arm, multi-stage, randomised phase 3 trial recruited patients with high-risk locally advanced or metastatic adenocarcinoma of the prostate staged by conventional imaging with isotope bone and CT scanning. This publication reports findings for the most recent STAMPEDE research question, testing the addition of metformin to standard of care for non-diabetic (glycated haemoglobin [HbA1c] <48 mmol/mol [equivalent to <6·5%]) patients with metastatic disease with adequate renal function (glomerular filtration rate ≥45 ml/min/1·73 m2) and WHO performance status 0–2. This trial recruited from 112 hospitals in the UK and Switzerland to the STAMPEDE protocol. Patients were randomly allocated (1:1) to standard of care or standard of care plus metformin 850 mg twice daily. Random assignment was by telephone using minimisation with a random element of 20% (developed and maintained by the MRC Clinical Trials Unit at UCL), stratified for randomising hospital, age (<70 years vs ≥70 years), WHO performance status (0 vs 1 or 2), type of ADT, regular long-term use of aspirin or non-steroidal anti-inflammatory drugs (NSAIDs; yes vs no), pelvic nodal status (positive vs negative), planned radiotherapy (yes vs no), and planned docetaxel or androgen receptor pathway inhibitor (ARPI) use (docetaxel vs abiraterone, enzalutamide, or apalutamide vs none). Standard of care comprised ADT with or without radiotherapy and with or without docetaxel or ARPI. The primary outcome measure was overall survival, defined as the time to death from any cause, assessed in the intention-to-treat population. Safety was assessed in patients who started treatment. The trial is registered with ClinicalTrials.gov, NCT00268476 and ISRCTN, ISRCTN78818544. Findings Between Sep 5, 2016, and Mar 31, 2023, 1874 patients with metastatic disease were randomly allocated to standard of care (n=938) or standard of care plus metformin (n=936). The median patient age was 69 years (IQR 63-73) and the median PSA was 84 ng/mL (24–352). 1758 (94%) of 1874 patients were newly diagnosed with metastatic disease and 116 (6%) were diagnosed with metachronous relapsing disease. 1543 (82%) of 1874 patients received ADT plus docetaxel and 52 (3%) received abiraterone, enzalutamide, or apalutamide. The median time to most recent case report form follow-up was 60 months (IQR 49–72). 473 deaths were reported in the standard of care group; median survival was 61·8 months (IQR 29·7 to not reached). There were 453 deaths in the metformin group; median survival was 67·4 months (32·5 to not reached; HR 0·91, 95% CI 0·80–1·03; p=0·15). Grade 3 or worse adverse events were reported in 487 (52%) of 938 patients in the standard of care group and 523 (57%) of 921 patients in the standard of care plus metformin group. 61 (7%) patients in the standard of care group and 84 (9%) patients in the standard of care plus metformin group reported at least one grade 3 or worse gastrointestinal adverse event; all other body systems showed no difference in grade 3 adverse events. There were six drug-related deaths in the standard of care group and one in the standard of care plus metformin group. Interpretation We did not find significant evidence of an overall survival benefit of adding metformin to standard of care in the overall population of patients with metastatic hormone-sensitive prostate cancer. The side-effect profile of metformin was as expected and consisted mainly of diarrhoea. Adverse metabolic side-effects of ADT were significantly reduced in the metformin group compared with the standard of care group

Metformin for patients with metastatic prostate cancer starting androgen deprivation therapy: a randomised phase 3 trial of the STAMPEDE platform protocol

Background Metformin is a widely used anti-diabetic drug. Several studies have suggested that metformin has anticancer activity in some malignancies, including prostate cancer. Metformin might also mitigate the adverse metabolic effects of androgen-deprivation therapy (ADT). We hypothesised that metformin might improve survival in patients with metastatic hormone-sensitive prostate cancer and reduce metabolic complications associated with ADT. Methods The STAMPEDE multi-arm, multi-stage, randomised phase 3 trial recruited patients with high-risk locally advanced or metastatic adenocarcinoma of the prostate staged by conventional imaging with isotope bone and CT scanning. This publication reports findings for the most recent STAMPEDE research question, testing the addition of metformin to standard of care for non-diabetic (glycated haemoglobin [HbA1c] <48 mmol/mol [equivalent to <6·5%]) patients with metastatic disease with adequate renal function (glomerular filtration rate ≥45 ml/min/1·73 m2) and WHO performance status 0–2. This trial recruited from 112 hospitals in the UK and Switzerland to the STAMPEDE protocol. Patients were randomly allocated (1:1) to standard of care or standard of care plus metformin 850 mg twice daily. Random assignment was by telephone using minimisation with a random element of 20% (developed and maintained by the MRC Clinical Trials Unit at UCL), stratified for randomising hospital, age (<70 years vs ≥70 years), WHO performance status (0 vs 1 or 2), type of ADT, regular long-term use of aspirin or non-steroidal anti-inflammatory drugs (NSAIDs; yes vs no), pelvic nodal status (positive vs negative), planned radiotherapy (yes vs no), and planned docetaxel or androgen receptor pathway inhibitor (ARPI) use (docetaxel vs abiraterone, enzalutamide, or apalutamide vs none). Standard of care comprised ADT with or without radiotherapy and with or without docetaxel or ARPI. The primary outcome measure was overall survival, defined as the time to death from any cause, assessed in the intention-to-treat population. Safety was assessed in patients who started treatment. The trial is registered with ClinicalTrials.gov, NCT00268476 and ISRCTN, ISRCTN78818544. Findings Between Sep 5, 2016, and Mar 31, 2023, 1874 patients with metastatic disease were randomly allocated to standard of care (n=938) or standard of care plus metformin (n=936). The median patient age was 69 years (IQR 63-73) and the median PSA was 84 ng/mL (24–352). 1758 (94%) of 1874 patients were newly diagnosed with metastatic disease and 116 (6%) were diagnosed with metachronous relapsing disease. 1543 (82%) of 1874 patients received ADT plus docetaxel and 52 (3%) received abiraterone, enzalutamide, or apalutamide. The median time to most recent case report form follow-up was 60 months (IQR 49–72). 473 deaths were reported in the standard of care group; median survival was 61·8 months (IQR 29·7 to not reached). There were 453 deaths in the metformin group; median survival was 67·4 months (32·5 to not reached; HR 0·91, 95% CI 0·80–1·03; p=0·15). Grade 3 or worse adverse events were reported in 487 (52%) of 938 patients in the standard of care group and 523 (57%) of 921 patients in the standard of care plus metformin group. 61 (7%) patients in the standard of care group and 84 (9%) patients in the standard of care plus metformin group reported at least one grade 3 or worse gastrointestinal adverse event; all other body systems showed no difference in grade 3 adverse events. There were six drug-related deaths in the standard of care group and one in the standard of care plus metformin group. Interpretation We did not find significant evidence of an overall survival benefit of adding metformin to standard of care in the overall population of patients with metastatic hormone-sensitive prostate cancer. The side-effect profile of metformin was as expected and consisted mainly of diarrhoea. Adverse metabolic side-effects of ADT were significantly reduced in the metformin group compared with the standard of care group

Dose-escalated Adaptive Radiotherapy for Bladder Cancer: Results of the Phase 2 RAIDER Randomised Controlled Trial

Delivering radiotherapy to the bladder is challenging as it is a mobile, deformable structure. Dose-escalated adaptive image-guided radiotherapy could improve outcomes. RAIDER aimed to demonstrate the safety of such a schedule. RAIDER is an international phase 2 noncomparative randomised controlled trial (ISRCTN26779187). Patients with unifocal T2-T4a urothelial bladder cancer were randomised (1:1:2) to standard whole bladder radiotherapy (WBRT), standard-dose adaptive radiotherapy (SART), or dose-escalated adaptive radiotherapy (DART). Two fractionation (f) schedules recruited independently. WBRT and SART dose was 55 Gy/20f or 64 Gy/32f, and DART dose was 60 Gy/20f or 70 Gy/32f. For SART and DART, a radiotherapy plan (small, medium, or large) was chosen daily. The primary endpoint was the proportion of patients with radiotherapy-related late Common Terminology Criteria for Adverse Events grade ≥3 toxicity; the trial was designed to rule out >20% toxicity with DART. A total of 345 patients were randomised between October 2015 and April 2020: 41/46 WBRT, 41/46 SART, and 81/90 DART patients in the 20f/32f cohorts, respectively. The median age was 72/73 yr; 78%/85% had T2 tumours, 46%/52% had neoadjuvant chemotherapy, and 70%/71% had radiosensitising therapy. The median follow-up was 42.1/38.2 mo. Sixty-six of 77 (86%) 20f and 74 of 82 (90%) 32f participants planned for DART met the mandatory medium plan dose constraints. Radiotherapy-related grade ≥3 toxicity was reported in one of 58 patients (90% confidence interval [CI] 0.1, 7.9) with 20f DART and zero of 56 patients with 32f DART. Two-year overall survival was 77% (95% CI 69, 82) for WBRT + SART and 80% (95% CI 73, 85) for DART (hazard ratio = 0.84, 95% CI 0.59, 1.21, p = 0.4). Thirteen of 345 (3.8%) participants had salvage cystectomy. Grade ≥3 late toxicity was low. DART was safe and feasible to deliver, meeting preset toxicity thresholds. Disease-related outcomes are promising for dose-escalated treatments, with a low salvage cystectomy rate and overall survival similar to that seen in cystectomy cohorts

The psychosocial impact of prostate cancer screening for BRCA1 and BRCA2 carriers

Objectives: To report the long-term outcomes from a longitudinal psychosocial study that forms part of the ‘Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted Screening in men at higher genetic risk and controls’ (IMPACT) study. The IMPACT study is a multi-national study of targeted prostate cancer (PrCa) screening in individuals with a known germline pathogenic variant (GPV) in either the BReast CAncer gene 1 (BRCA1) or the BReast CAncer gene 2 (BRCA2). Subjects and Methods: Participants enrolled in the IMPACT study were invited to complete a psychosocial questionnaire prior to each annual screening visit for a minimum of 5 years. The questionnaire included questions on sociodemographics and the following measures: Hospital Anxiety and Depression Scale, Impact of Event Scale, 36-item Short-Form Health Survey, Memorial Anxiety Scale for PrCa, Cancer Worry Scale, risk perception and knowledge. Results: A total of 760 participants completed questionnaires: 207 participants with GPV in BRCA1, 265 with GPV in BRCA2 and 288 controls (non-carriers from families with a known GPV). We found no evidence of clinically concerning levels of general or cancer-specific distress or poor health-related quality of life in the cohort as a whole. Individuals in the control group had significantly less worry about PrCa compared with the carriers; however, all mean scores were low and within reported general population norms, where available. BRCA2 carriers with previously high prostate-specific antigen (PSA) levels experience a small but significant increase in PrCa anxiety (P = 0.01) and PSA-specific anxiety (P < 0.001). Cancer risk perceptions reflected information provided during genetic counselling and participants had good levels of knowledge, although this declined over time. Conclusion: This is the first study to report the longitudinal psychosocial impact of a targeted PrCa screening programme for BRCA1 and BRCA2 carriers. The results reassure that an annual PSA-based screening programme does not have an adverse impact on psychosocial health or health-related quality of life in these higher-risk individuals. These results are important as more PrCa screening is targeted to higher-risk groups

Duration of androgen deprivation therapy with postoperative radiotherapy for prostate cancer: a comparison of long-course versus short-course androgen deprivation therapy in the RADICALS-HD randomised trial

Background Previous evidence supports androgen deprivation therapy (ADT) with primary radiotherapy as initial treatment for intermediate-risk and high-risk localised prostate cancer. However, the use and optimal duration of ADT with postoperative radiotherapy after radical prostatectomy remains uncertain. Methods RADICALS-HD was a randomised controlled trial of ADT duration within the RADICALS protocol. Here, we report on the comparison of short-course versus long-course ADT. Key eligibility criteria were indication for radiotherapy after previous radical prostatectomy for prostate cancer, prostate-specific antigen less than 5 ng/mL, absence of metastatic disease, and written consent. Participants were randomly assigned (1:1) to add 6 months of ADT (short-course ADT) or 24 months of ADT (long-course ADT) to radiotherapy, using subcutaneous gonadotrophin-releasing hormone analogue (monthly in the short-course ADT group and 3-monthly in the long-course ADT group), daily oral bicalutamide monotherapy 150 mg, or monthly subcutaneous degarelix. Randomisation was done centrally through minimisation with a random element, stratified by Gleason score, positive margins, radiotherapy timing, planned radiotherapy schedule, and planned type of ADT, in a computerised system. The allocated treatment was not masked. The primary outcome measure was metastasis-free survival, defined as metastasis arising from prostate cancer or death from any cause. The comparison had more than 80% power with two-sided α of 5% to detect an absolute increase in 10-year metastasis-free survival from 75% to 81% (hazard ratio [HR] 0·72). Standard time-to-event analyses were used. Analyses followed intention-to-treat principle. The trial is registered with the ISRCTN registry, ISRCTN40814031, and ClinicalTrials.gov , NCT00541047 . Findings Between Jan 30, 2008, and July 7, 2015, 1523 patients (median age 65 years, IQR 60–69) were randomly assigned to receive short-course ADT (n=761) or long-course ADT (n=762) in addition to postoperative radiotherapy at 138 centres in Canada, Denmark, Ireland, and the UK. With a median follow-up of 8·9 years (7·0–10·0), 313 metastasis-free survival events were reported overall (174 in the short-course ADT group and 139 in the long-course ADT group; HR 0·773 [95% CI 0·612–0·975]; p=0·029). 10-year metastasis-free survival was 71·9% (95% CI 67·6–75·7) in the short-course ADT group and 78·1% (74·2–81·5) in the long-course ADT group. Toxicity of grade 3 or higher was reported for 105 (14%) of 753 participants in the short-course ADT group and 142 (19%) of 757 participants in the long-course ADT group (p=0·025), with no treatment-related deaths. Interpretation Compared with adding 6 months of ADT, adding 24 months of ADT improved metastasis-free survival in people receiving postoperative radiotherapy. For individuals who can accept the additional duration of adverse effects, long-course ADT should be offered with postoperative radiotherapy. Funding Cancer Research UK, UK Research and Innovation (formerly Medical Research Council), and Canadian Cancer Society

Bladder Preservation for Muscle-Invasive Bladder Cancer With Variant Histology

A growing body of evidence has shown bladder-preservation with chemo-radiotherapy achieves comparable survival to Radical Cystectomy (5-year OS 50%-70%) and superior quality of life outcomes for patients with muscle-invasive urothelial carcinoma of the bladder (UC). However, up to 55% of patients harbor variant histology and in this review we aim to clarify the role of bladder-preservation for this group. We first draw the distinction between urothelial carcinoma with divergent differentiation (UCDD) and non-urothelial carcinoma (NUC). UCDD is common, increasing in prevalence, and whilst each subtype may have its own characteristics current evidence suggests comparable outcomes with radical cystectomy and bladder-preservation. Non-urothelial carcinoma is a collection of distinct pathologies each deserving of its own management strategy. However, these tumors are rare, and evidence is generated from retrospective studies with significant inherent bias. Small cell carcinoma of the bladder has good evidence for bladder-preservation; however, other pathologies such as Squamous Cell Carcinoma and Adenocarcinoma are not well supported. We recommend careful multidisciplinary appraisal of the evidence for each subtype and honest patient discussion about the limited evidence before reaching management decisions. As we look to the future molecular-profiling may help better characterize these tumors and aid in treatment selection