The impact of a delay in initiating radiation therapy on prostate-specific antigen outcome for patients with clinically localized prostate carcinoma.
BACKGROUND
To determine whether a delay in initiating external beam radiation therapy (RT) following diagnosis could impact prostate-specific antigen (PSA) outcome for patients with localized prostate cancer, 460 patients, who received 3D conformal RT to a median dose of 70.4 Gy for clinically localized prostate cancer between 1992 and 2001, were studied.


METHODS
The primary endpoint was PSA failure (American Society for Therapeutic Radiology and Oncology definition). Estimates of PSA control were made using the Kaplan-Meier method. Delay was defined as the time between diagnosis and the start of RT. Risk groups were defined based on known predictors of PSA outcome, namely, baseline PSA level, clinical T-category, Gleason score, and percentage of biopsy cores positive for tumor. Cox multivariate regression analysis was used to determine the ability of treatment delay to predict time to PSA failure after adjusting for the other known predictors.


RESULTS
Treatment delay independently predicted time to PSA failure following diagnosis for high-risk (Adjusted Hazard Ratio = 1.08 per month; P = 0.029) but not low-risk patients (P = 0.31). Patients with high-risk disease (n = 240) had 5-year estimates of PSA failure-free survival of 55% versus 39% (Plog-rank = 0.014) for those with delay < 2.5 months versus > or = 2.5 months respectively. The median delay was 2.5 months.


CONCLUSIONS
Treatment delay adversely affected PSA outcome for high-risk patients but not for low-risk patients following RT.
Nguyen
Paul L
PL
Department of Radiation Oncology, Brigham and Women's Hospital, Dana Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA.
Whittington
Richard
R
Koo
Sophia
S
Schultz
Delray
D
Cote
Kerri B
KB
Loffredo
Marian
M
McMahon
Elizabeth
E
Renshaw
Andrew A
AA
Tomaszewski
John E
JE
D'Amico
Anthony V
AV
D000230:Adenocarcinoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000368:Aged; D001706:Biopsy; D015331:Cohort Studies; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000473:pathology; D011467:Prostate / Q000528:radiation effects; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D011877:Radionuclide Imaging; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D012307:Risk Factors; D012669:Seminal Vesicles / Q000528:radiation effects; D013997:Time Factors; D016896:Treatment Outcome
D017430:Prostate-Specific Antigen