Improved outcomes with dose escalation in localized prostate cancer treated with precision image-guided radiotherapy

Publication date: Available online 20 April 2017
Source:Radiotherapy and Oncology
Author(s): Hamid Raziee, Fabio Y. Moraes, Jure Murgic, Melvin L.K. Chua, Melania Pintilie, Peter Chung, Cynthia Ménard, Andrew Bayley, Mary Gospodarowicz, Padraig Warde, Tim Craig, Charles Catton, Robert G. Bristow, David A. Jaffray, Alejandro Berlin
Background and purposeDose-escalated radiotherapy (DE) improves outcomes in localized prostate cancer (PCa). The impact of DE in the context of image-guided radiotherapy (IGRT) remains unknown. Herein, we determined outcomes of three sequential cohorts treated with progressive DE-IGRT.Materials and methodsWe analyzed data from 1998 to 2012. Patients treated with radical radiotherapy were included, with three sequential institutional schedules: (A) 75.6Gy, (B) 79.8Gy, (C) 78Gy, with 1.8, 1.9 and 2Gy/fraction, respectively. IGRT consisted of fiducial markers and daily EPID (A, B) or CBCT (C).Results961 patients were included, with median follow-up of 6.1y. 30.5%, 32.6% and 36.9% were treated in A, B and C, respectively. Risk category distribution was 179 (18.6%) low-, 653 (67.9%) intermediate- and 129 (13.5%) high-risk. PSA, T-category, androgen deprivation use and risk distribution were similar among groups.BCR (biochemical recurrence) was different (p<0.001) between A, B and C with 5-year rates of 23%, 17% and 9%, respectively (HR 2.68 [95% CI 1.87–3.85] and 1.92 [95% CI 1.33–2.78] for A and B compared to C, respectively). Findings were most significant in the intermediate-risk category. Metastasis, cause-specific-death and toxicities were not different between cohorts.ConclusionOur findings suggest continuous BCR improvement with progressive DE-IGRT. Prospective validation considering further DE with IGRT seems warranted.



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