As reported in the Journal of Clinical Oncology by Guricová et al, 10-year outcomes of the Dutch-Belgian phase III FLAME trial showed continued benefit of a focal radiotherapy boost to the intraprostatic tumor in patients receiving external-beam radiotherapy (EBRT) for localized prostate cancer.
Study Details
In the trial, 557 patients (intention-to-treat population) with intermediate- or high-risk disease were randomly assigned between 2009 and 2015 to receive standard EBRT at 77 Gy in 35 fractions to the whole prostate gland (n = 276) or standard EBRT with a focal boost of up to 95 Gy in magnetic resonance imaging–detected lesions (n = 281). Initial 5-year results showed a significant improvement in biochemical disease–free survival in the focal boost group with no additional toxicity.
Key Findings
At 10 years, biochemical disease–free survival was 86% in the focal boost group vs 71% in the standard group (P < .001). Significant differences favoring the focal boost group were also observed for 10-year disease-free survival (81% vs 67%, P < .001), local disease–free survival (95% vs 86%, P < .01), and regional lymph node disease-free survival (94% vs 85%, P < .01). No significant differences between the focal boost group vs the standard group were observed for distant metastasis–free survival (P = .17) or overall survival (P =.77).
Dose-response analysis suggested an association between focal boost dose and distant metastatic failure, with higher doses being associated with reduced risk of distant metastatic failure.
The investigators concluded: “The 10-year results demonstrated the sustained benefit of focal boosting on [biochemical disease-free survival]. By preventing biochemical failure, men are spared the potential burden of [prostate cancer] recurrence.”
Uulke A. van der Heide, PhD, of the Department of Radiation Oncology, the Netherlands Cancer Institute, Amsterdam, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by the Dutch Cancer Society. For full disclosures of all study authors, visit ascopubs.org.
