Moderate dose escalation in three-dimensional conformal localized prostate cancer radiotherapy: single-institutional experience in 398 patients comparing 66 Gy versus 70 Gy versus 74 Gy.
OBJECTIVE
To evaluate the clinical outcome in prostate cancer patients treated at one single institution by the implementation of moderate dose escalation.


METHODS
A total of 398 patients with histologically verified localized prostate cancer (T1-3 Nx0 Mx0) were treated by three-dimensional conformal radiotherapy with/without additional hormonal therapy. Risk group distribution was as follows: 106 low-risk (27%), 164 intermediate-risk (41%), and 128 high-risk (32%) patients. Total local dose was increased from 66 Gy (1994-1998) to 70 Gy (1998-2003) and 74 Gy (1998-2005). Biochemical no evidence of disease (bNED: ASTRO/Phoenix definition) and late gastrointestinal/urogenital side effects (EORTC/RTOG) were assessed.


RESULTS
Median follow-up was 64 months. The 5-year bNED rates according to 66 Gy, 70 Gy and 74 Gy were 37%, 64% and 63% (ASTRO), and 54%, 74% and 69% (Phoenix), respectively. In multivariate analysis, age and T-stage were significant in predicting bNED. The 5-year bNED rates (ASTRO) according to 66 Gy, 70 Gy and 74 Gy were 40%, 78% and 73% in the low-risk group, 41%, 55% and 85% in the intermediate-risk group, and 30%, 53% and 52% in the high-risk group. Intermediate-risk patients showed a significant improvement of bNED by increasing the dose up to 74 Gy. The 5-year actuarial rates of gastrointestinal/urogenital side effects grade > or = 2 were 18%/16% (66 Gy), 20%/24% (70 Gy), and 27%/28% (74 Gy).


CONCLUSIONS
A benefit of local doses at a level of > or = 70 Gy could be detected showing the highest increase of prostate-specific antigen control in the intermediate-risk group. The amount of patients reporting of severe late side effects is small.
Goldner
Gregor
G
Department of Radiotherapy, University of Vienna Medical School, Vienna, Austria. Gregor.Goldner@akhwien.at
Dimopoulos
Johannes
J
Kirisits
Christian
C
Pötter
Richard
R
D000230:Adenocarcinoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019583:Dose Fractionation, Radiation; D005500:Follow-Up Studies; D041981:Gastrointestinal Tract / Q000528:radiation effects; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000379:methods*; D014566:Urogenital System / Q000528:radiation effects