Long-term durability of PSA failure-free survival after radiotherapy for localized prostate cancer.
OBJECTIVE
To determine the durability of prostate-specific antigen (PSA) progression-free survival beyond 5 years in patients biochemically free of relapse 5 years after external beam radiotherapy (EBRT).


METHODS
This study identified 328 men treated with EBRT to the prostate who were biochemically (American Society for Therapeutic Radiology and Oncology definition) disease free 5 years after treatment. The median follow-up was 7.4 years. The patients were divided into four groups according to their PSA values 5 years after treatment: PSA <or=0.5, 0.5 to <or=1.0, 1.0 to <or=2.0, and 2.0-4.0 ng/mL. PSA progression-free rates were calculated in each subgroup at 10 years after treatment. Yearly hazard rates of biochemical progression were also calculated for the 5-10 years after treatment.


RESULTS
The PSA progression-free survival rate was 87%, 79%, and 67%, respectively, 8, 10, and 13 years after treatment in patients biochemically free of disease 5 years after treatment. The progression-free rates at 10 years after treatment according to the PSA level at 5 years was 92% for PSA <or=0.5 ng/mL; 71% for PSA 0.5 to <or=1.0 ng/mL; 78% for PSA 1.0 to <or=2.0 ng/mL; and 56% for PSA 2.0 to <or=4.0. The lower the PSA level at 5 years, the more durable the probability of maintained biochemical disease-free survival (p <0.0001). The yearly hazard rates of biochemical progression ranged from 3.1% to 6.6% in the 5-10 years after RT.


CONCLUSIONS
When PSA levels remain low (<2 ng/mL) 5 years after EBRT, the great majority of patients will be biochemically disease free at 10 years. The hazard rates of biochemical progression in the 6-10 years after treatment are low and are comparable to those published for prostatectomy series.
Yock
Torunn I
TI
Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
Zietman
Anthony L
AL
Shipley
William U
WU
Thakral
Harjot K
HK
Coen
John J
JJ
D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology / Q000532:radiotherapy*; D013997:Time Factors
D017430:Prostate-Specific Antigen