A phase II study of localized prostate cancer treated to 75.6 Gy with 3D conformal radiotherapy.
OBJECTIVE
To prospectively evaluate toxicity, biochemical failure-free survival (bFFS) and biopsy-proven local control for prostate cancer patients treated with 75.6 Gy in 42 fractions using 6-field conformal radiotherapy to prostate alone.


METHODS
From 1997 to 1999, 140 patients with T1-2NxM0, Gleason score<or=8, and PSA<or=20 ng/ml prostate cancer were assessed using Radiation Therapy Oncology Group acute and late toxicity scores. bFFS was determined for 120 patients treated without hormones. Post-treatment prostate biopsies were performed at a median of 3 years and a late toxicity questionnaire was administered at a median of 5 years.


RESULTS
Clinically important acute toxicities were gastrointestinal (GI) grade 2: 22% and 3: 0%, and genitourinary (GU) grade 2: 24% and 3: 2%. Late physician-assessed toxicities were GI>or=grade 2: 2%, and GU>or=grade 2: 1%. The 3-year bFFS of patients failure-free before biopsy was 93% (95% CI: 83-100) from a negative biopsy and 22% (95% CI: 0-56) from a positive biopsy (P=0.001). Patients reported significantly more late toxicity than physicians (GI: P=0.003, GU: P<0.001). At 5.0 years median follow-up, cause-specific survival was 98% (95% CI: 96-100), overall survival was 91% (95% CI: 86-97), and bFFS was 55% (95% CI: 45-64).


CONCLUSIONS
75.6 Gy caused modest levels of acute and late toxicity. Three-year biopsies predicted subsequent biochemical outcome.
Nichol
Alan
A
Radiation Medicine Program, Princess Margaret Hospital and University of Toronto, Toronto, Canada.
Chung
Peter
P
Lockwood
Gina
G
Rosewall
Tara
T
Divanbiegi
Lorella
L
Sweet
Joan
J
Toi
Ants
A
Bayley
Andrew
A
Bristow
Rob
R
Crook
Juanita
J
Gospodarowicz
Mary
M
McLean
Michael
M
Milosevic
Michael
M
Warde
Padraig
P
Catton
Charles
C
D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D000368:Aged; D001706:Biopsy; D018572:Disease-Free Survival; D006801:Humans; D007422:Intestines / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D015996:Survival Rate; D001743:Urinary Bladder / Q000528:radiation effects