Prediction of PSA bounce after permanent prostate brachytherapy for localized prostate cancer.
BACKGROUND
We aimed to calculate the frequency and features of the development of a prostate-specific antigen (PSA) bounce after prostate brachytherapy alone, to correlate the bounce with clinical and dosimetric factors and to identify factors that predict PSA bounce.


METHODS
PSA bounce was evaluated in 86 patients with T1-T2 prostate cancer who underwent radioactive seed implantation using iodine-125 (I-125) without hormonal therapy or external-beam radiation therapy (EBRT) from September 2004 to December 2007. A PSA bounce was defined as a rise of at least 0.4 ng/ml greater than a previous PSA level with a subsequent decline equal to, or less than, the initial nadir.


RESULTS
Calculated by the Kaplan-Meier method, the incidence of PSA bounce at a 2-year follow-up was 26%. Median time to the PSA bounce was 15 months. Univariate analysis demonstrated that age, dose received by 90% of the prostate gland (D90), volume of gland receiving 100% of the prescribed dose (V100), and V150 were significantly associated with the PSA bounce, while pretreatment PSA level, Gleason score, pretreatment prostate volume, clinical T stage, and V200 were not. In multivariate analysis, age 67 years or less and D90 more than 180 Gy were identified as independent factors for predicting the PSA bounce (P < 0.05).


CONCLUSIONS
PSA bounce is not a rare phenomenon after prostate brachytherapy. It is more common in younger patients and patients receiving higher doses of radiation.
Kanai
Kunimitsu
K
Department of Urology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
Nakashima
Jun
J
Sugawara
Akitomo
A
Shigematsu
Naoyuki
N
Nagata
Hirohiko
H
Kikuchi
Eiji
E
Miyajima
Akira
A
Nakagawa
Ken
K
Kubo
Atsushi
A
Oya
Mototsugu
M
D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood; D001918:Brachytherapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000532:radiotherapy*; D016896:Treatment Outcome
D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen