Long-term multi-institutional analysis of stage T1-T2 prostate cancer treated with radiotherapy in the PSA era.
OBJECTIVE
To report the long-term outcome for patients with Stage T1-T2 adenocarcinoma of the prostate definitively irradiated in the prostate-specific antigen (PSA) era.


METHODS
Nine institutions combined data on 4839 patients with Stage T1b, T1c, and T2 adenocarcinoma of the prostate who had a pretreatment PSA level and had received >or=60 Gy as definitive external beam radiotherapy. No patient had hormonal therapy before treatment failure. The median follow-up was 6.3 years. The end point for outcome analysis was PSA disease-free survival at 5 and 8 years after therapy using the American Society for Therapeutic Radiology and Oncology (ASTRO) failure definition.


RESULTS
The PSA disease-free survival rate for the entire group of patients was 59% at 5 years and 53% at 8 years after treatment. For patients who had received >or=70 Gy, these percentages were 61% and 55%. Of the 4839 patients, 1582 had failure by the PSA criteria, 416 had local failure, and 329 had distant failure. The greatest risk of failure was at 1.5-3.5 years after treatment. The failure rate was 3.5-4.5% annually after 5 years, except in patients with Gleason score 8-10 tumors for whom it was 6%. In multivariate analysis for biochemical failure, pretreatment PSA, Gleason score, radiation dose, tumor stage, and treatment year were all significant prognostic factors. The length of follow-up and the effect of backdating as required by the ASTRO failure definition also significantly affected the outcome results. Dose effects were most significant in the intermediate-risk group and to a lesser degree in the high-risk group. No dose effect was seen at 70 or 72 Gy in the low-risk group.


CONCLUSIONS
As follow-up lengthens and outcome data accumulate in the PSA era, we continue to evaluate the efficacy and durability of radiotherapy as definitive therapy for early-stage prostate cancer. Similar studies with higher doses and more contemporary techniques will be necessary to explore more fully the potential of this therapeutic modality.
Kuban
Deborah A
DA
Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston 77030, USA. dakuban@mdanderson.org
Thames
Howard D
HD
Levy
Larry B
LB
Horwitz
Eric M
EM
Kupelian
Patrick A
PA
Martinez
Alvaro A
AA
Michalski
Jeff M
JM
Pisansky
Thomas M
TM
Sandler
Howard M
HM
Shipley
William U
WU
Zelefsky
Michael J
MJ
Zietman
Anthony L
AL
D000230:Adenocarcinoma / Q000097:blood* / Q000473:pathology / Q000532:radiotherapy*; D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood; D009367:Neoplasm Staging; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D012016:Reference Values; D017211:Treatment Failure; D016896:Treatment Outcome
D017430:Prostate-Specific Antigen