Acute toxicity of three-dimensional conformal radiotherapy in prostate cancer patients eligible for implant monotherapy.
OBJECTIVE
To assess the acute toxicity of three-dimensional conformal radiotherapy (3D-CRT) in prostate cancer patients eligible for implant monotherapy.


METHODS
Between December 1991 and June 1998, 198 prostate cancer patients were treated with 3D-CRT at the University of California Davis Medical Center. Fifty-two of these patients had a prostate-specific antigen (PSA) level </= 10.0 ng/ml, Gleason score </= 6, and a 1997 AJCC clinical stage T1bN0-T2bN0. Eleven (21%) patients received radiotherapy to the prostate and seminal vesicles; the remaining patients were treated to the prostate only. The 3D-CRT treatment planning guidelines in Radiation Therapy Oncology Group (RTOG) 9406 were followed after 1994 (similar treatment planning was used before the protocol became available). Typically, 4 oblique and 2 lateral fields were treated. All patients were seen at least weekly while under treatment, 1 month postirradiation and then every 3 months. Total radiation doses ranged from 66.0-79.2 Gy, with a median dose of 73.8 Gy in 41 fractions over 8 weeks. Acute toxicity is described according to the RTOG acute toxicity scoring system.


RESULTS
Overall, 3D-CRT was well-tolerated: 29% of patients experienced RTOG Grade 1 and 27% experienced Grade 2 acute lower gastrointestinal (GI) toxicity. Forty percent and 33% of patients experienced Grade 1 and 2 acute genitourinary (GU) toxicity, respectively. As expected, more acute morbidity, especially GI, was observed with a larger clinical target volume (prostate and seminal vesicles versus prostate only; p = 0. 05). Neoadjuvant hormonal therapy did not increase the incidence or severity of radiation-induced side effects. No acute toxicity >/= Grade 3, e.g., hourly nocturia, gross hematuria, diarrhea requiring parenteral support, narcotics for pain control, or catheterization for acute urinary retention, was observed.


CONCLUSIONS
Although relatively high doses of radiation are delivered to prostate cancers with 3D-CRT compared with conventional radiotherapy, 3D-CRT is surprisingly well-tolerated. No patients in the cohort eligible for implant monotherapy experienced acute toxicity >/= Grade 3.
Chou
R H
RH
Department of Radiation Oncology, University of California Davis, Sacramento, CA, USA.
Wilder
R B
RB
Ji
M
M
Ryu
J K
JK
Leigh
B R
BR
Earle
J D
JD
Doggett
R L
RL
Kubo
H D
HD
Roach
M
M
deVere White
R W
RW
D000208:Acute Disease; D001918:Brachytherapy / Q000379:methods*; D004064:Digestive System / Q000528:radiation effects*; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D012189:Retrospective Studies; D014555:Urination Disorders / Q000209:etiology*