Postoperative intensity modulated radiation therapy in high risk prostate cancer: a dosimetric comparison.
The aim of this study was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal technique (3D-CRT), with respect to target coverage and irradiation of organs at risk for high dose postoperative radiotherapy (PORT) of the prostate fossa. 3D-CRT and IMRT treatment plans were compared with respect to dose to the rectum and bladder. The dosimetric comparison was carried out in 15 patients considering 2 different scenarios: (1) exclusive prostate fossa irradiation, and (2) pelvic node irradiation followed by a boost on the prostate fossa. In scenario (1), a 3D-CRT plan (box technique) and an IMRT plan were calculated and compared for each patient. In scenario (2), 3 treatment plans were calculated and compared for each patient: (a) 3D-CRT box technique for both pelvic (prophylactic nodal irradiation) and prostate fossa irradiation (3D-CRT only); (b) 3D-CRT box technique for pelvic irradiation followed by an IMRT boost to the prostatic fossa (hybrid 3D-CRT and IMRT); and (c) IMRT for both pelvic and prostate fossa irradiation (IMRT only). For exclusive prostate fossa irradiation, IMRT significantly reduced the dose to the rectum (lower Dmean, V50%, V75%, V90%, V100%, EUD, and NTCP) and the bladder (lower Dmean, V50%, V90%, EUD and NTCP). When prophylactic irradiation of the pelvis was also considered, plan C (IMRT only) performed better than plan B (hybrid 3D-CRT and IMRT) as respect to both rectum and bladder irradiation (reduction of Dmean, V50%, V75%, V90%, equivalent uniform dose [EUD], and normal tissue complication probability [NTCP]). Plan (b) (hybrid 3D-CRT and IMRT) performed better than plan (a) (3D-CRT only) with respect to dose to the rectum (lower Dmean, V75%, V90%, V100%, EUD, and NTCP) and the bladder (Dmean, EUD, and NTCP). Postoperative IMRT in prostate cancer significantly reduces rectum and bladder irradiation compared with 3D-CRT.
Digesú
Cinzia
C
Department of Radiotherapy, John Paul II Center for High Technology Research and Education in Biomedical Sciences, Catholic University, Campobasso, Italy.
Cilla
Savino
S
De Gaetano
Andrea
A
Massaccesi
Mariangela
M
Macchia
Gabriella
G
Ippolito
Edy
E
Deodato
Francesco
F
Panunzi
Simona
S
Iapalucci
Chiara
C
Mattiucci
Gian Carlo
GC
D'Angelo
Elisa
E
Padula
Gilbert D A
GD
Valentini
Vincenzo
V
Cellini
Numa
N
Piermattei
Angelo
A
Morganti
Alessio G
AG
D000368:Aged; D003131:Combined Modality Therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy* / Q000601:surgery; D011874:Radiometry; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated