The prognostic value of PSA kinetics in untreated prostate cancer (PCa) patients is debatable. We investigated the association between PSA doubling time (PSAdt), PSA velocity (PSAvel), and PSAvel risk count (PSAvRC) and PCa mortality in a cohort of patients with localised PCa managed on watchful waiting.
Patients with clinically localised PCa managed observationally, who were randomised to and remained on placebo for minimum 18 months in the SPCG-6 study, were included. All patients survived at least two years and had a minimum of three PSA determinations available. The prognostic value of PSA kinetics was analysed and patients were stratified according to their PSA at consent: ≤10 ng/mL, 10. 1-25 ng/mL, and >25 ng/mL. Cumulative incidences of PCa-specific mortality were estimated with the Aalen-Johansen method.
263 patients were included of which 116, 76 and 71 had a PSA at consent ≤10 ng/mL, 10. 1-25 ng/mL, and >25 ng/mL, respectively. Median follow-up was 13. 6 years. For patients with PSA at consent between 10. 1-25 ng/mL, the 13-year risks of PCa mortality were associated with PSA kinetics: PSAdt ≤3 years: 62. 0% vs. PSAdt >3 years: 16. 3% (Gray's test: p<0. 0001), PSAvel >2 ng/mL/year: 48. 0% vs. PSAvel ≤2 ng/mL/year: 11. 0% (Gray's test: p=0. 0008), and PSAvRC 2: 45. 0% vs. 0-1: 3. 8% (Gray's test: p=0. 001). In contrast, none of the PSA kinetics were significantly associated with changes of 13-year risks of PCa mortality in patients with PSA at consent ≤10 ng/mL or >25 ng/mL.
We found that magnitude changes in 13-year risks of PCa mortality that can be indicated by PSA kinetics depend on PSA level in patients with localised PCa who were managed observationally. Our results question PSA kinetics as surrogate marker for PCa mortality in patients with low and high PSA values.
NCT00672282.
Annals of oncology : official journal of the European Society for Medical Oncology / ESMO. 2015 Dec 17 [Epub ahead of print]
F B Thomsen, K Brasso, K D Berg, T A Gerds, J-E Johansson, A Angelsen, T L J Tammela, P Iversen, Scandinavian Prostate Cancer Group
Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark. , Department of Biostatistics, University of Copenhagen, Copenhagen, Denmark. , Department of Urology, Faculty of Medicine and Health, Örebro University, Örebro, Sweden. , Faculty of Medicine, Norwegian University of Technology and Science, Trondheim, Norway. , Department of Surgery, Tampere University Hospital and School of Medicine, University of Tampere, Tampere, Finland. , Copenhagen Prostate Cancer Center, Department of Urology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.