Patients’ Preferences for Cytoreductive Treatments in Newly Diagnosed Metastatic Prostate Cancer: The IP5-MATTER Study

This is the first study, to the authors’ knowledge, to report that patients are willing to accept additional cytoreductive treatments to the prostate and metastases for progression-free and survival benefits. We report willingness to accept 10 percentage-point increases in urinary incontinence and fatigue to gain 3.4 and 2.7 mo of post-treatment survival time, respectively. These results can be used to support policy on the commissioning and delivery of current, and emerging, cytoreductive treatments for newly diagnosed metastatic prostate cancer. Cytoreductive treatments for patients diagnosed with de novo synchronous metastatic hormone-sensitive prostate cancer (mHSPC) confer incremental survival benefits over systemic therapy, but these may lead to added toxicity and morbidity. Our objective was to determine patients’ preferences for, and trade-offs between, additional cytoreductive prostate and metastasis-directed interventions. A prospective multicentre discrete choice experiment trial was conducted at 30 hospitals in the UK between December 3, 2020 and January 25, 2023 (NCT04590976). The individuals were eligible for inclusion if they were diagnosed with de novo synchronous mHSPC within 4 mo of commencing androgen deprivation therapy and had performance status 0–2. A discrete choice experiment instrument was developed to elicit patients’ preferences for cytoreductive prostate radiotherapy, prostatectomy, prostate ablation, and stereotactic ablative body radiotherapy to metastasis. Patients chose their preferred treatment based on seven attributes. An error-component conditional logit model was used to estimate the preferences for and trade-offs between treatment attributes. A total of 352 patients were enrolled, of whom 303 completed the study. The median age was 70 yr (interquartile range [IQR] 64–76) and prostate-specific antigen was 94 ng/ml (IQR 28–370). Metastatic stages were M1a 10.9% (33/303), M1b 79.9% (242/303), and M1c 7.6% (23/303). Patients preferred treatments with longer survival and progression-free periods. Patients were less likely to favour cytoreductive prostatectomy with systemic therapy (Coef. –0.448; [95% confidence interval {CI} –0.60 to –0.29]; p