Comparison of treatment volumes and techniques in prostate cancer radiation therapy.
OBJECTIVE
To compare dose-volume histograms (DVHs) for 3 target volumes (group 1, prostate + seminal vesicles + pelvic lymph nodes; group 2, prostate + seminal vesicles; group 3, prostate only) to determine the difference in dose to normal structures (rectum, bladder, and femoral heads) while controlling for target dose using 3-dimensional conformal radiation therapy (3DCRT) versus intensity modulated radiation therapy (IMRT).


METHODS
Ten patients with localized prostate cancer were randomly selected. 3DCRT and IMRT planning were done to deliver 75.6 Gy to the prostate, 50.4 Gy to the pelvic nodes, and 55.8 Gy to the seminal vesicles at a standard fractionation of 1.8 Gy. An additional plan delivering 75.6 Gy to the seminal vesicles using IMRT was run. DVHs were compared for 3DCRT and IMRT.


RESULTS
In all 3 groups, the percent rectum receiving > or =70 Gy, > or =60 Gy, and > or =40 Gy was significantly less for IMRT than for 3DCRT. Increasing target volumes, as necessary for pelvic nodal irradiation, overall did not result in higher rectal doses for IMRT. With 3DCRT, however, larger target volumes did increase the amount of rectum irradiated. Similar results were obtained for the femoral heads whereas results for the bladder were mixed.


CONCLUSIONS
When compared with 3DCRT, IMRT delivered equivalent or higher doses to the target volume with greater sparing of critical organs. Because dose-volume parameters have been shown to relate to toxicity, IMRT would appear to be the favored technique for prostate cancer radiation, particularly with regard to nodal treatment.
Lee
Catherine T
CT
Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA.
Dong
Lei
L
Ahamad
Anesa W
AW
Choi
Haesun
H
Cheung
Rex
R
Lee
Andrew K
AK
Horne
David F
DF
Breaux
Allan J
AJ
Kuban
Deborah A
DA
D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D005270:Femur Head / Q000528:radiation effects; D006801:Humans; D007421:Intestine, Small / Q000528:radiation effects; D008198:Lymph Nodes / Q000473:pathology / Q000528:radiation effects; D015182:Lymphatic Irradiation; D008297:Male; D009928:Organ Specificity; D011467:Prostate / Q000473:pathology / Q000528:radiation effects; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000517:prevention & control; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012007:Rectum / Q000528:radiation effects; D012669:Seminal Vesicles / Q000473:pathology / Q000528:radiation effects; D047368:Tumor Burden; D001743:Urinary Bladder / Q000528:radiation effects