Prostate cancer boost using high-dose-rate brachytherapy: early toxicity analysis of 3 different fractionation schemes.
OBJECTIVE
To analyse early toxicity of high-dose-rate brachytherapy (HDRB) boost for prostate cancer using 3 fractionation schemes.


METHODS
From February 2009 to May 2012, after the first course of external beam radiation therapy (EBRT 46 Gy/23 f), 124 patients underwent HDRB boost for low (7%), intermediate (19%), and high-risk (73%) prostate cancers. From February to December 2009, Group 1 (G1) = 18 Gy/3 f/2 d (24%); from January 2010 to April 2011, Group 2 (G2) = 18 Gy/2 f/2 d (42%), and from May to September 2011, Group 3 (G3) = 14 Gy/1 f/1 d (34%). Planning and CT-scan was performed before each fraction. Dose constraints for G1/G2 were V100 rectum = 0 and V125 urethra = 0, while for G3 V90 rectum = 0 and V115 urethra = 0. Genito-urinary (GU) and Gastro-intestinal (GI) acute toxicities were assessed at 1 month (for the 3 fractionation schemes) and 6 months (for 18 Gy/3 f and 18 Gy/2 f) after the boost (CTCv3.0).


RESULTS
Median follow-up was 25 months (8-46.9), median age was 71 years (50-82), and median CTV was 31 cc (16-71). The grades of acute GI and GU toxicities at 1 and 6 months after HDRB were mainly Grade 1 with few Grade 2 (GU: 5% at 1 month; GI: 1% at 6 months). One patient developed G4 sepsis toxicity 2 days after HDRB and recovered without after-effects. No significant differences were observed at 1 and 6 months after the HDRB between treatment groups.


CONCLUSIONS
The right fractionation remains under discussion, but prostate cancer HDRB boost using a single fraction (providing similar results in terms of acute toxicity) is more comfortable for the patient, and less time consuming for the medical staff.
Department of Radiotherapy, Antoine Lacassagne Cancer Center, University of Nice-Sophia, Nice, France ; Department of Radiotherapy, King Abdulaziz University Hospital, Jeddah, Saudi Arabia.
Hussam
H
Hijazi
Urology Department, Pasteur Academic Hospital, Nice.
Daniel
D
Chevallier
Statistic Unit, Antoine Lacassagne Cancer Center, Nice, France.
Jocelyn
J
Gal
Department of Radiotherapy, Antoine Lacassagne Cancer Center, University of Nice-Sophia, Nice, France.
Marie-Eve
ME
Chand
Department of Radiotherapy, Antoine Lacassagne Cancer Center, University of Nice-Sophia, Nice, France.
Mathieu
M
Gautier
Department of Radiotherapy, Antoine Lacassagne Cancer Center, University of Nice-Sophia, Nice, France.
Jean-Michel
JM
Hannoun-Levi
boost; early toxicity; fractionation; high-dose-rate brachytherapy; prostate cancer