Long-term prostate cancer control using palladium-103 brachytherapy and external beam radiotherapy in patients with a high likelihood of extracapsular cancer extension.
OBJECTIVE
To report the long-term biochemical control rates with brachytherapy-based treatment for patients with prostate cancer at high risk of extracapsular cancer extension.


METHODS
A total of 243 consecutive patients with at least one higher risk factor (Gleason score of 7 or worse, prostate-specific antigen [PSA] level greater than 10 ng/mL, or elevated prostatic acid phosphatase level greater than 2.5 U) who were treated with palladium-103 plus supplemental external beam radiotherapy from 1992 through 1996 were included in this study. Patients received 41 Gy external beam radiotherapy to a limited pelvic field, followed 4 weeks later by a palladium-103 boost. The prescribed minimal palladium-103 dose to the prostate was 80 to 90 Gy. Freedom from biochemical failure was defined as a serum PSA level of 0.2 ng/mL or less at the last follow-up visit.


RESULTS
Of the 243 patients, 41 developed biochemical failure. The overall actuarial freedom from biochemical progression rate at 13 years was 81%, with 198 patients followed up for longer than 5 years. The overall actuarial freedom from failure rate for the 93 patients with a PSA level of 10 ng/mL or greater and Gleason score of 7 or greater was 74% at 5 years and 72% at 10 years. The overall actuarial freedom from failure rate for the 66 patients with elevated prostatic acid phosphatase was 65% at 10 years. The absolute risk of failure decreased progressively with time, falling to 1% by 6 years after treatment. On Cox proportional hazard multivariate analysis, considering each factor as a continuous variable, the strongest predictor of failure was the acid phosphatase level (P <0.0001), followed by Gleason score (P = 0.42) and PSA level (P = 0.15).


CONCLUSIONS
The evidence from this patient group at high risk of extracapsular cancer extension suggests that the relatively high tumor control rates with brachytherapy-based therapy are durable.
Dattoli
Michael
M
Dattoli Cancer Center and Brachytherapy Research Institute, Sarasota, Florida 34217, USA. brachymd@aol.com
Wallner
Kent
K
True
Lawrence
L
Cash
Jennifer
J
Sorace
Richard
R
D000368:Aged; D001707:Biopsy, Needle; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods*; D002277:Carcinoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009367:Neoplasm Staging; D010165:Palladium / Q000627:therapeutic use*; D011336:Probability; D016016:Proportional Hazards Models; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011868:Radioisotopes / Q000627:therapeutic use; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy / Q000009:adverse effects / Q000379:methods*; D018570:Risk Assessment; D016019:Survival Analysis; D013997:Time Factors; D016896:Treatment Outcome
D011868:Radioisotopes; D010165:Palladium; D017430:Prostate-Specific Antigen