[The impact of 3D image guided prostate brachytherapy on therapeutic ratio: the Quebec University Hospital experience].
OBJECTIVE
To evaluate the impact of adaptative image-guided brachytherapy on therapeutic outcome and toxicity in prostate cancer.


METHODS
The 1,110 first patients treated at the CHUQ-l'Hôtel-Dieu de Québec were divided in five groups depending on the technique used for the implantation, the latest being intra operative treatment planning. Biochemical disease free survival (5-bDFS), toxicities and dosimetric parameters were compared between the groups.


RESULTS
5-bDFS (ASTRO+Houston) were of 88.5% and 90.5% for the whole cohort. The use of intra operative treatment planning resulted in better dosimetric parameters. Clinically, this resulted in a decreased use of urethral catheterism, from 18.8% in group 1 to 5.2% in group 5, and in a reduction in severe acute urinary side effects (21.3 vs 33.3% P=0.01) when compared with preplanning. There was also less late gastrointestinal side effects (groups 5 vs 1: 26.6 vs 43.2% P<0.05). Finally, when compared with preplanning, intra operative treatment planning was associated with a smaller reduction between planned D90 and the dose calculated at the CT scan 1 month after the implant (38 vs 66 Gy).


CONCLUSIONS
The evolution of prostate brachytherapy technique toward intra operative treatment planning allowed dosimetric gains which resulted in significant clinical benefits by increasing the therapeutic ratio mainly through a decreased urinary toxicity. A longer follow-up will answer the question whether there is an impact on 5-bDFS.
Foster
W
W
Département de radiothérapie oncologique, CHUQ l'Hôtel-Dieu de Québec, 11, côte du Palais, G1R 2J6 Québec, Canada.
Beaulieu
L
L
Harel
F
F
Martin
A-G
AG
Vigneault
E
E
D000368:Aged; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D018572:Disease-Free Survival; D006785:Hospitals, University; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000032:analysis; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging*; D011792:Quebec; D011859:Radiography; D013997:Time Factors
D017430:Prostate-Specific Antigen