Veerle Groen, MD from the University Medical Center Utrecht, Radiation Oncology, Utrecht, the Netherlands speaks about Focal Boost to the Intraprostatic Tumor in External Beam Radiotherapy for Patients With Localized Prostate Cancer: Results From the FLAME Randomized Phase III Trial.
Link to Study:
BRIEF DESCRIPTION OF THE OBJECTIVE
The aim of this study is to see whether using external beam radiotherapy to improve the macroscopic visible tumor improves biochemical disease-free survival (bDFS) in patients with localized prostate cancer.
PATIENTS AND TECHNIQUES
Between 2009 and 2015, 571 patients with low- and high-risk prostate cancer were enrolled in phase III, multicenter, randomized managed Focal Lesion Ablative Microboost in Prostate Cancer trial. Patients who received standard care received 77 Gy to the entire prostate (in 2.2 Gy fractions). The intraprostatic lesion visible on multiparametric magnetic resonance imaging was given an additional simultaneous integrated focal boost up to 95 Gy (fractions up to 2.7 Gy) in the focal boost arm. Organs at risk were given precedence over the focal boost dose. The 5-year bDFS was the primary endpoint. Disease-free survival (DFS), distant metastases-free survival, prostate cancer-specific survival, overall survival, toxicity, and health-related quality of life were used as secondary endpoints.
The average duration of follow-up was 72 months. The focal boost arm had a slightly higher biochemical DFS than the regular arm (hazard ratio 0.45, 95 percent CI 0.28 to 0.71, P.001). bDFS was 92 percent and 85 percent at 5-year follow-up, respectively. Prostate cancer-specific survival (P =.49) and total survival (P =.50) did not vary significantly. In the regular arm, the combined incidence of late genitourinary and GI toxicity grade 2 was 23 percent and 12 percent, respectively, compared to 28 percent and 13 percent in the focal boost arm. Differences were limited and not statistically important in both late toxicity and health-related quality of life.
The addition of a focal boost to the intraprostatic lesion increased bDFS without affecting toxicity or quality of life in patients with localized low- and high-risk prostate cancer. The Focal Lesion Ablative Microboost in Prostate Cancer study found that using a high focal boost strategy to increase tumor control while staying within organ at risk dose constraints is both successful and safe.