High-dose intensity modulated radiation therapy for prostate cancer: early toxicity and biochemical outcome in 772 patients.
OBJECTIVE
To report the acute and late toxicity and preliminary biochemical outcomes in 772 patients with clinically localized prostate cancer treated with high-dose intensity-modulated radiotherapy (IMRT).


METHODS
Between April 1996 and January 2001, 772 patients with clinically localized prostate cancer were treated with IMRT. Treatment was planned using an inverse-planning approach, and the desired beam intensity profiles were delivered by dynamic multileaf collimation. A total of 698 patients (90%) were treated to 81.0 Gy, and 74 patients (10%) were treated to 86.4 Gy. Acute and late toxicities were scored by the Radiation Therapy Oncology Group morbidity grading scales. PSA relapse was defined according to The American Society of Therapeutic Radiation Oncology Consensus Statement. The median follow-up time was 24 months (range: 6-60 months).


RESULTS
Thirty-five patients (4.5%) developed acute Grade 2 rectal toxicity, and no patient experienced acute Grade 3 or higher rectal symptoms. Two hundred seventeen patients (28%) developed acute Grade 2 urinary symptoms, and one experienced urinary retention (Grade 3). Eleven patients (1.5%) developed late Grade 2 rectal bleeding. Four patients (0.1%) experienced Grade 3 rectal toxicity requiring either one or more transfusions or a laser cauterization procedure. No Grade 4 rectal complications have been observed. The 3-year actuarial likelihood of >/= late Grade 2 rectal toxicity was 4%. Seventy-two patients (9%) experienced late Grade 2 urinary toxicity, and five (0.5%) developed Grade 3 urinary toxicity (urethral stricture). The 3-year actuarial likelihood of >/= late Grade 2 urinary toxicity was 15%. The 3-year actuarial PSA relapse-free survival rates for favorable, intermediate, and unfavorable risk group patients were 92%, 86%, and 81%, respectively.


CONCLUSIONS
These data demonstrate the feasibility of high-dose IMRT in a large number of patients. Acute and late rectal toxicities seem to be significantly reduced compared with what has been observed with conventional three-dimensional conformal radiotherapy techniques. Short-term PSA control rates seem to be at least comparable to those achieved with three-dimensional conformal radiotherapy at similar dose levels. Based on this favorable risk:benefit ratio, IMRT has become the standard mode of conformal treatment delivery for localized prostate cancer at our institution.
Zelefsky
Michael J
MJ
Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA. zelefskm@mskcc.org
Fuks
Zvi
Z
Hunt
Margie
M
Yamada
Yoshiya
Y
Marion
Christine
C
Ling
C Clifton
CC
Amols
Howard
H
Venkatraman
E S
ES
Leibel
Steven A
SA
D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D020266:Radiotherapy, Conformal / Q000379:methods*; D012008:Recurrence; D013997:Time Factors; D016896:Treatment Outcome