Surveillance and follow-up of early prostate cancer

Sammanfattning: Active surveillance (AS) for prostate cancer was introduced to address overtreatment resulting from prostate-specific antigen (PSA) testing. Despite advancements such as Magnetic Resonance Imaging (MRI) and targeted biopsies, PSA remains crucial in prostate cancer diagnostics, leading to ongoing challenges of overdiagnosis and overtreatment. This thesis aimed to investigate different aspects of AS and follow-up of early prostate cancer and provide new insights to reduce overtreatment and enhance surveillance and follow-up. In Paper I, the rationale and methodology of a randomized controlled trial, the Prostate Cancer Active Surveillance Trigger trial/Scandinavian Prostate Cancer Group study no. 17 (PCASTt/SPCG17), were outlined. This trial's objective is to evaluate the safety of an AS protocol based on MRI and standardized triggers for repeat biopsies and transition to radical treatment. Patient recruitment is anticipated to conclude in 2024. Paper II investigated the risks of biochemical recurrence, metastatic disease, and prostate cancer-related death in patients following radical prostatectomy. The analysis was conditioned on time after radical prostatectomy without biochemical recurrence. For patients with favourable histopathology in prostatectomy specimens and no biochemical recurrence five years post-prostatectomy, the probability of developing metastatic disease or dying from prostate cancer within 20 years after surgery was very low. This suggests shorter follow-up for selected patients. Paper III compared outcomes of AS for men from different healthcare regions in Sweden with varying traditions of AS. Regions with lower uptake in AS demonstrated a higher probability of transitioning from AS to radical treatment, but no difference in AS failure. The results suggest overtreatment in regions with low uptake in AS. Paper IV explored the associations between potential triggers for transitioning from AS to radical treatment and the transition to treatment. We analysed how this association changed with the introduction of prostate MRI. We found an increasingly strong association between triggers, particularly histopathological progression, and transition. However, most treated men had not experienced histopathological progression. The introduction of MRI did not contribute much to the change. In conclusion, this thesis outlines an ongoing study on defined triggers for transitioning from AS to radical treatment, suggests shorter follow-up after radical prostatectomy for selected patients, reveals overtreatment in regions with low uptake in AS, and shows an increasing use of histopathological progression as a trigger for transition to radical treatment.