PURPOSE: To assess the magnitude of dosimetric reductions of a focal and ultra-focal high-dose rate (HDR) prostate brachytherapy treatment strategy relative to standard whole gland (WG) treatment.
METHODS AND MATERIALS: HDR brachytherapy plans for five patients treated with WG HDR monotherapy were optimized to assess different treatment strategies. Plans were generated to treat the hemigland (HG), one-third gland (1/3G), and one-sixth gland (1/6G), as well as to assess treating the WG with a boost to one of those sub-volumes (WG + HG, WG + 1/3G, WG + 1/6G). Dosimetric parameters analyzed included Target D90%, V100%, V150%, Bladder (B), Rectal (R), Urethral (U) D0.1, 1 and 2cc, Urethral V75%, and the V50% to the contralateral HG. Two-tailed t tests were used for comparison of means, and p-values less than 0.05 were considered statistically significant.
RESULTS: Target objectives (D90 > 100% and V100 > 97%) were met in all cases. Significant organs at risk dose reductions were achieved for all approaches compared with WG plans. 1/6G vs WG plans resulted in the greatest reduction in dose with a mean bladder D2cc 24.7 vs 64.8%, rectal D2cc 32.8 vs 65.3%, urethral D1cc 52.1 vs 103.8%, and V75 14.5 vs 75% (p < 0.05 for all comparisons).
CONCLUSION: Significant dose reductions to organs at risk can be achieved using HDR focal brachytherapy. The magnitude of the reductions achievable with treating progressively smaller sub-volumes suggests the potential to reduce morbidity, but the clinical impact on morbidity and tumor control remain to be investigated.
Written by:
Banerjee R, Park SJ, Anderson E, Demanes DJ, Wang J, Kamrava M. Are you the author?
Department of Oncology, University of Calgary, Calgary, Alberta T2N 4N2, Canada; Department of Radiation Oncology, University of California Los Angeles (UCLA), Los Angeles, CA 90095, USA.
Reference: Brachytherapy. 2015 Feb 10. pii: S1538-4721(15)00002-1.
doi: 10.1016/j.brachy.2014.12.007
PubMed Abstract
PMID: 25680768