The STAMPEDE2 Trial: a Site Survey of Current Patterns of Care, Access to Imaging and Treatment of Metastatic Prostate Cancer

Abstract

Aims: The forthcoming STAMPEDE2 trial has three comparisons in metastatic hormone-sensitive prostate cancer. We aim to determine clinical practices among STAMPEDE trial investigators for access to imaging and therapeutic choices and explore their interest in participation in STAMPEDE2.

Materials and methods: The survey was developed and distributed online to 120 UK STAMPEDE trial sites. Recipients were invited to complete the survey between 16 and 30 May 2022. The survey consisted of 30 questions in five sections on access to stereotactic ablative body radiotherapy (SABR), 177lutetium-prostate-specific membrane antigen-617 (¹⁷⁷Lu-PSMA-617), choice of systemic therapies and use of positron emission tomography/computerised tomography and whole-body magnetic resonance imaging.

Results: From 58/120 (48%) sites, 64 respondents completed the survey: 55/64 (86%) respondents were interested to participate in SABR, 44/64 (69%) in ¹⁷⁷Lu-PSMA-617 and 56/64 (87.5%) in niraparib with abiraterone comparisons; 45/64 (70%) respondents had access to bone, spine and lymph node metastases SABR delivery and 7/64 (11%) to ¹⁷⁷Lu-PSMA-617. In addition to androgen deprivation therapy, 60/64 (94%) respondents used androgen receptor signalling inhibitors and 46/64 (72%) used docetaxel; 29/64 (45%) respondents would consider triplet therapy with androgen deprivation therapy, androgen receptor signalling inhibitors and docetaxel. Positron emission tomography/computerised tomography was available to 62/64 (97%) respondents and requested by 45/64 (70%) respondents for disease uncertainty on conventional imaging and 39/64 (61%) at disease relapse. Whole-body magnetic resonance imaging was available to 24/64 (38%) respondents and requested by 13/64 (20%) respondents in highly selected patients. In low-volume disease, 38/64 (59%) respondents requested scans at baseline and disease relapse. In high-volume disease, 29/64 (45%) respondents requested scans at baseline, best response (at prostate-specific antigen nadir) and disease relapse; 54/64 (84%) respondents requested computerised tomography and bone scan for best response assessment.

Conclusion: There is noteworthy disparity in clinical practice across current study sites, however most have expressed an interest in participation in the forthcoming STAMPEDE2 trial.

Keywords: 177lutetium-PSMA-617; metastatic hormone-sensitive prostate cancer; niraparib; positron emission tomography/computerised tomography; prostate-specific membrane antigen; stereotactic ablative body radiotherapy.