The ProtecT trial: analysis of the patient cohort, baseline risk stratification and disease progression

Objective: To test the hypothesis that the baseline clinico-pathological features of the men with localized prostate cancer (PCa) included in the ProtecT (Prostate Testing for Cancer and Treatment) trial who progressed (n = 198) at a 10-year median follow-up were different from those of men with stable disease (n = 1409). Patients and Methods: We stratified the study participants at baseline according to risk of progression using clinical disease stage, pathological grade and PSA level, using Cox proportional hazard models. Results: The findings showed that 34% of participants (n = 505) had intermediate- or high-risk PCa, and 66% (n = 973) had low-risk PCa. Of 198 participants who progressed, 101 (51%) had baseline International Society of Urological Pathology Grade Group 1, 59 (30%) Grade Group 2, and 38 (19%) Grade Group 3 PCa, compared with 79%, 17% and 5%, respectively, for 1409 participants without progression (P < 0.001). In participants with progression, 38% and 62% had baseline low- and intermediate-/high-risk disease, compared with 69% and 31% of participants with stable disease (P < 0.001). Treatment received, age (65–69 vs 50–64 years), PSA level, Grade Group, clinical stage, risk group, number of positive cores, tumour length and perineural invasion were associated with time to progression (P ≤ 0.005). Men progressing after surgery (n = 19) were more likely to have a higher Grade Group and pathological stage at surgery, larger tumours, lymph node involvement and positive margins. Conclusions: We demonstrate that one-third of the ProtecT cohort consists of people with intermediate-/high-risk disease, and the outcomes data at an average of 10 years' follow-up are generalizable beyond men with low-risk PCa.