Dose escalation to the dominant intraprostatic lesion defined by sextant biopsy in a permanent prostate I-125 implant: a prospective comparative toxicity analysis.
OBJECTIVE
Using real-time intraoperative inverse-planned permanent seed prostate implant (RTIOP/PSI), multiple core biopsy maps, and three-dimensional ultrasound guidance, we planned a boost volume (BV) within the prostate to which hyperdosage was delivered selectively. The aim of this study was to investigate the potential negative effects of such a procedure.


METHODS
Patients treated with RTIOP/PSI for localized prostate cancer with topographic biopsy results received an intraprostatic boost (boost group [BG]). They were compared with patients treated with a standard plan (reference group [RG]). Plans were generated using a simulated annealing inverse planning algorithm. Prospectively recorded urinary, rectal, and sexual toxicities and dosimetric parameters were compared between groups.


RESULTS
The study included 120 patients treated with boost technique who were compared with 70 patients treated with a standard plan. Boost technique did not significantly change the number of seeds (55.1/RG vs. 53.6/BG). The intraoperative prostate V150 was slightly higher in BG (75.2/RG vs. 77.2/BG, p = 0.039). Urethra V100, urethra D90, and rectal D50 were significantly lower in the BG. No significant differences were seen in acute or late urinary, rectal, or sexual toxicities.


CONCLUSIONS
Because there were no differences between the groups in acute and late toxicities, we believe that BV can be planned and delivered to the dominant intraprostatic lesion without increasing toxicity. It is too soon to say whether a boost technique will ultimately increase local control.
Gaudet
Marc
M
Département de radio-oncologie, L'Hôtel-Dieu de Québec, Québec, QC, Canada.
Vigneault
Eric
E
Aubin
Sylviane
S
Varfalvy
Nicolas
N
Harel
François
F
Beaulieu
L
L
Martin
André-Guy
AG
D000368:Aged; D000465:Algorithms; D001706:Biopsy / Q000379:methods; D001918:Brachytherapy / Q000379:methods*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011467:Prostate / Q000000981:diagnostic imaging / Q000473:pathology* / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000532:radiotherapy*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000009:adverse effects / Q000379:methods; D012007:Rectum / Q000528:radiation effects; D018084:Ultrasonography, Interventional / Q000379:methods; D014521:Urethra / Q000528:radiation effects
D007457:Iodine Radioisotopes