Prostate-specific antigen after neoadjuvant androgen suppression in prostate cancer patients receiving short-term androgen suppression and external beam radiotherapy: pooled analysis of four NRG Oncology RTOG randomized clinical trials
Menée à partir des données de 4 essais cliniques portant sur 2 404 patients atteints d'un cancer de la prostate et ayant reçu un traitement anti-androgénique néo-adjuvant ainsi qu'une radiothérapie externe en combinaison avec un traitement anti-adrogénique de courte durée (durée médiane de suivi : 9,4 ans), cette étude évalue l'association entre le niveau sérique du PSA après le traitement anti-androgénique néo-adjuvant et les résultats cliniques à long terme (échec biochimique, échec local, risque de métastases distantes, mortalité spécifique et mortalité toutes causes confondues)
Purpose : To validate if prostate specific antigen (PSA) level after neoadjuvant androgen suppression (neoAS) is associated with long-term outcome after neoAS and external radiation therapy (RT) with concurrent short-term AS in prostate cancer patients.
Methods : 2404 patients treated with neoAS prior to RT and concurrent AS (without post-RT AS) were pooled from trials A, B, C, and D. Multivariable models were used to test associations between the pre-specified dichotomized post-neoAS, pre-RT PSA (≤0.1 vs. >0.1 ng/mL) groupings and clinical outcomes.
Results : Median follow-up for surviving patients was 9.4 years. Median post-neoAS, pre-RT PSA was 0.3 ng/mL, with 32% of patients ≤0.1 ng/mL. Race, Gleason score, T-stage, N-stage, pre-treatment PSA, and duration of neoAS were associated with the groups of patients with PSA ≤0.1 and >0.1 ng/mL. In univariate analyses, post-neoAS, pre-RT PSA >0.1 ng/mL was associated with increased risks of biochemical failure (hazard ratio [HR] 2.04; p<0.0001), local failure (HR 2.51; p<0.0001), distant metastases (HR 1.73; p=0.0006), cause-specific mortality (HR 2.36; p<0.0001), and all-cause mortality (HR 1.24; p=0.005). In multivariable models that also included baseline and treatment variables, post-neoAS, pre-RT PSA >0.1 ng/mL was independently associated with increased risk of biochemical failure (HR 2.00; p<0.0001), local failure (HR 2.33; p<0.0001), and cause-specific mortality (HR 1.75; p=0.03).
Conclusion : Patients with PSA >0.1 ng/mL after neoAS and before RT start had less favorable clinical outcomes than patients with PSA was ≤0.1 ng/mL. The role of post-neoAS, pre-RT PSA presently, relative to PSA obtained along the continuum of medical care, is not presently defined, but could be tested in future clinical trials.
International Journal of Radiation Oncology • Biology • Physics , résumé, 2018