Patients diagnosed with metastatic prostate cancer at first diagnosis or de novo synchronous metastatic hormone-sensitive prostate cancer (mHSPC) have had reported increases in overall survival due to rapid advances and intensification of systemic therapy regimes beyond traditional androgen deprivation therapy (ADT). This has created an oncological ‘window of opportunity’ to explore the benefit of ‘cytoreductive’ treatments to the residual primary tumour and metastases, in an attempt to achieve further disease control. Such treatments do not provide cure but may reduce cancer burden, prolong life, and extend time without cancer progression. Cytoreductive radical prostatectomy, prostate radiotherapy, prostate ablation (e.g. cryotherapy) and stereotactic ablative body radiotherapy (SABR) to metastases have all been explored in recent randomised trials. The IP5-MATTER prospective multicentre discrete choice experiment trial was conducted at 30 hospitals in the United Kingdom (Dec 2020 – Jan 2023; NCT04590976). The objective was to determine patients’ preferences for, and trade-offs between, additional cytoreductive prostate and metastasis-directed interventions. Newly-diagnosed mHSPC within four months of commencing ADT were included. A discrete choice experiment instrument allowed researchers to understand how patients trade-off between the treatments. The trade-off in this study was whether patients were willing to accept the likely increased toxicity with additional treatments in exchange for potential extended months of life or months without their cancer progressing further. Overall, 303 completed the study with a median age of 70 years (IQR 64–76) and PSA 94ng/ml (IQR 28–370). The researchers found that patients preferred all treatments with longer survival and progression-free periods. However, patients were less likely to favour cytoreductive prostatectomy with systemic therapy (Coef. –0.448; [95% CI –0.60 to –0.29]; p<0.001), unless it was combined with SABR. When trade-offs were calculated, patients were willing to accept an additional treatment with 10-percentage point increases in the risk of urinary incontinence and fatigue to gain 3.4 months (95% CI 2.8–4.3) and 2.7 months (95% CI 2.3–3.1) of overall survival, respectively. Patient preference studies are important in assessing whether most patients would be accepting of the benefit from novel treatments, especially surgery in a non-curative setting. We learn from this study that most patients would be accepting of the morbidity of the only current guideline recommended treatment, cytoreductive prostate radiotherapy. However, as further information is reported from surgical randomised studies (e.g., SWOG 1802, IP2-ATLANTA) this information can be used to help assist with commissioning of any alternative combinations of local and metastasis-directed treatments that are reported to be beneficial.
Patients’ preferences for additional (cytoreductive) treatments to the prostate and metastasis in metastatic prostate cancer
Reviewed by Martin J Connor
Patients’ preferences for cytoreductive treatments in newly diagnosed metastatic prostate cancer: the IP5-MATTER study.
