MRI-informed active surveillance outcomes and dietary fibre acceptability: the Aberdeen experience

Objectives To describe active surveillance (AS) outcomes following introduction of an MRI-informed pathway, examine whether baseline PI-RADS/Likert scores identify men with earlier AS discontinuation, and assess the acceptability of dietary fibre supplementation in men on AS. Patients and methods We conducted a retrospective audit of 420 men enrolled in AS at Aberdeen Royal Infirmary between 2012 and 2022. Men were grouped into an MRI-informed pathway (n=198) or biopsy-first pathway (n=222). Time to AS discontinuation for any reason was analysed using Kaplan-Meier methods and log-rank tests. An exploratory analysis compared men with baseline PI-RADS/Likert scores of 4-5 and 2-3. Ten men on AS also completed semi-structured interviews analysed using the Theoretical Framework of Acceptability. Results Median follow-up was 3.1 years (IQR 1.6-5.1). Overall, 208 men (49.5%) discontinued AS, including 176 because of disease progression. Median time to discontinuation was 4.9 years (95% CI 4.4-5.6). It was shorter in the MRI-informed pathway than in the biopsy-first pathway (4.1 vs 5.6 years; log-rank p<0.01). Among 167 men with recorded baseline MRI scores, 44 (26.3%) had PI-RADS/Likert 4-5. Median time to discontinuation was 2.9 years in this group compared with 4.0 years for scores 2-3 (p<0.01). Interview participants were generally willing to consider dietary fibre supplementation, although gastrointestinal effects and study procedures were anticipated burdens. Conclusion AS discontinuation occurred earlier in the MRI-informed pathway, although differences in patient selection and surveillance practice should be considered when interpreting this finding. PI-RADS/Likert 4-5 identified a sizeable subgroup with earlier all-cause AS discontinuation that may help inform recruitment to future intervention studies. Dietary fibre supplementation was acceptable in principle, supporting further feasibility work.