The Importance of Local Control in Early Stage Prostate Cancer: Outcomes of Patients with a Positive Post-Radiotherapy Biopsy Treated on RTOG 9408
Menée sur 831 patients atteints d'un cancer localisé de la prostate traité par radiothérapie en combinaison ou non avec un traitement anti-androgénique, cette étude évalue l'association entre le résultat positif d'une biopsie réalisée après la radiothérapie et le taux d'échecs biochimiques, le taux de métastases distantes ou la survie spécifique des patients
Purpose : To assess the association of positive post-radiotherapy (RT) biopsy with subsequent clinical outcomes in men with localized prostate cancer.
Methods : RTOG 94-08 analyzed 1979 men with stage T1b-T2b, PSA ≤ 20 prostate cancer testing whether 4 months of total androgen suppression (TAS) added to RT improved survival over RT alone. Patients randomized to TAS received flutamide with leutenizing hormone releasing hormone (LHRH) agonist. Per protocol, patients without evidence of clinical recurrence or initiation of additional endocrine therapy underwent repeat prostate biopsy 2 years following RT completion. Statistical analysis was performed to evaluate the impact of positive post-RT biopsies on clinical outcomes.
Results : 831 patients underwent post-RT biopsy, 398 treated with RT alone and 433 RT + TAS. Patients with positive post-RT biopsies had higher rates of biochemical failure (BCF) [HR=1.7; 95% CI 1.3-2.1] and distant metastasis (DM) [HR=2.4; 95% CI 1.3-4.4] as well as inferior disease specific survival (DSS) [HR=3.8; 95% CI 1.9-7.5]. Positive biopsy remained predictive of such outcomes after correction for potential confounders such as Gleason score, tumor stage, and TAS administration. Prior TAS did not prevent elevated risk of adverse outcome in the setting of post-RT positive biopsy. Patients with Gleason score > 7 with a positive biopsy additionally had inferior overall survival compared to those with a negative biopsy [HR=1.56; 95% CI 1.04-2.35].
Conclusions : Positive post-RT biopsy is associated with increased rates of DM and inferior DSS in patients treated with definitive RT and was associated with inferior OS for patients with high-grade tumors.
International Journal of Radiation Oncology • Biology • Physics , résumé, 2014