Incidence of late rectal and urinary toxicities after three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for localized prostate cancer.
OBJECTIVE
To report the incidence and predictors of treatment-related toxicity at 10 years after three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) for localized prostate cancer.


METHODS
Between 1988 and 2000, 1571 patients with stages T1-T3 prostate cancer were treated with 3D-CRT/IMRT with doses ranging from 66 to 81 Gy. The median follow-up was 10 years. Posttreatment toxicities were all graded according to the National Cancer Institute's Common Terminology Criteria for Adverse Events.


RESULTS
The actuarial likelihood at 10 years for the development of Grade>or=2 GI toxicities was 9%. The use of IMRT significantly reduced the risk of gastrointestinal (GI) toxicities compared with patients treated with conventional 3D-CRT (13% to 5%; p<0.001). Among patients who experienced acute symptoms the 10-year incidence of late toxicity was 42%, compared with 9% for those who did not experience acute symptoms (p<0.0001). The 10-year incidence of late Grade>or=2 genitourinary (GU) toxicity was 15%. Patients treated with 81 Gy (IMRT) had a 20% incidence of GU symptoms at 10 years, compared with a 12% for patient treated to lower doses (p=0.01). Among patients who had developed acute symptoms during treatment, the incidence of late toxicity at 10 years was 35%, compared with 12% (p<0.001). The incidence of Grade 3 GI and GU toxicities was 1% and 3%, respectively.


CONCLUSIONS
Serious late toxicity was unusual despite the delivery of high radiation dose levels in these patients. Higher doses were associated with increased GI and GU Grade 2 toxicities, but the risk of proctitis was significantly reduced with IMRT. Acute symptoms were a precursor of late toxicities in these patients.
Zelefsky
Michael J
MJ
Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA. zelefskm@mskcc.org
Levin
Emily J
EJ
Hunt
Margie
M
Yamada
Yoshiya
Y
Shippy
Alison M
AM
Jackson
Andrew
A
Amols
Howard I
HI
D000368:Aged; D000369:Aged, 80 and over; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011349:Proctitis / Q000209:etiology; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology* / Q000473:pathology; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects; D012007:Rectum / Q000528:radiation effects*; D013997:Time Factors; D001743:Urinary Bladder / Q000528:radiation effects*; D014566:Urogenital System / Q000528:radiation effects