PSA bounce predicts early success in patients with permanent iodine-125 prostate implant.
OBJECTIVE
To determine the clinical and dosimetric factors that predict prostate-specific antigen (PSA) bounce after iodine-125 prostate brachytherapy and to determine the predictive value of PSA bounce relative to biochemical relapse-free survival (bRFS).


METHODS
A multivariate analysis of factors thought to predict for PSA bounce was performed in 295 consecutive patients with T1-T2 prostate cancer treated by prostate brachytherapy as the sole radiotherapeutic modality and a minimum follow-up of 2 years. The variables examined included age, initial PSA level, biopsy Gleason score, use of androgen deprivation, occurrence of PSA bounce, dose received by 90% of the prostate gland, and volume of gland receiving 100% of the prescribed dose. A PSA bounce was defined as a rise of at least 0.2 ng/mL greater than a previous PSA level with a subsequent decline equal to, or less than, the initial nadir. A second analysis investigating the same factors and adding PSA bounce as a predictor of bRFS was also performed.


RESULTS
The median follow-up was 38 months. A PSA bounce was noted in 82 (28%) of 295 patients. On multivariate analysis, only younger age (younger than 65 years) significantly predicted for a PSA bounce. Patients who experienced a PSA bounce were less likely to have biochemical failure (P = 0.037). Overall, the bRFS rate at 5 years in those experiencing a PSA bounce was 100% versus 92% in those with no bounce.


CONCLUSIONS
Immediate salvage therapy in patients with a rising PSA level after permanent prostate brachytherapy should not be initiated provided the PSA increase does not exceed the pretreatment PSA value. A PSA bounce may be associated with improved bRFS but was not associated with any of the pretreatment clinical and dosimetric factors examined.
Patel
Chandrika
C
Department of Radiation Oncology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
Elshaikh
Mohamed A
MA
Angermeier
Kenneth
K
Ulchaker
James
J
Klein
Eric A
EA
Chehade
Nabil
N
Wilkinson
D Allan
DA
Reddy
Chandana A
CA
Ciezki
Jay P
JP
D000230:Adenocarcinoma / Q000097:blood / Q000188:drug therapy / Q000532:radiotherapy*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000726:Androgen Antagonists / Q000627:therapeutic use; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood*; D001918:Brachytherapy; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists; D006801:Humans; D007457:Iodine Radioisotopes / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009363:Neoplasm Proteins / Q000097:blood*; D011237:Predictive Value of Tests; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000188:drug therapy / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D012307:Risk Factors; D016879:Salvage Therapy; D016896:Treatment Outcome
D000726:Androgen Antagonists; D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D009363:Neoplasm Proteins; D007987:Gonadotropin-Releasing Hormone; D017430:Prostate-Specific Antigen