Low‐risk prostate lesions: An evidence review to inform discussion on losing the “cancer” label

Background Active surveillance (AS) mitigates harms from overtreatment of low‐risk prostate lesions. Recalibration of diagnostic thresholds to redefine which prostate lesions are considered “cancer” and/or adopting alternative diagnostic labels could increase AS uptake and continuation. Methods We searched PubMed and EMBASE to October 2021 for evidence on: (1) clinical outcomes of AS, (2) subclinical prostate cancer at autopsy, (3) reproducibility of histopathological diagnosis, and (4) diagnostic drift. Evidence is presented via narrative synthesis. Results AS: one systematic review (13 studies) of men undergoing AS found that prostate cancer‐specific mortality was 0%−6% at 15 years. There was eventual termination of AS and conversion to treatment in 45%−66% of men. Four additional cohort studies reported very low rates of metastasis (0%−2.1%) and prostate cancer‐specific mortality (0%−0.1%) over follow‐up to 15 years. Overall, AS was terminated without medical indication in 1%−9% of men. Subclinical reservoir: 1 systematic review (29 studies) estimated that the subclinical cancer prevalence was 5% at 79 years. Four additional autopsy studies (mean age: 54−72 years) reported prevalences of 12%−43%. Reproducibility: 1 recent well‐conducted study found high reproducibility for low‐risk prostate cancer diagnosis, but this was more variable in 7 other studies. Diagnostic drift: 4 studies provided consistent evidence of diagnostic drift, with the most recent (published 2020) reporting that 66% of cases were upgraded and 3% were downgraded when using contemporary diagnostic criteria compared to original diagnoses (1985−1995). Conclusions Evidence collated may inform discussion of diagnostic changes for low‐risk prostate lesions.