Prostate specific antigen-monitored combination radiotherapy for patients with prostate cancer. I-125 implant followed by external-beam radiation.
BACKGROUND
Because results of retropubic I-125 implantation for prostate cancer have been poor, external beam radiation was added postimplant. Serum prostate specific antigen (PSA) was used to assess this approach of combined irradiation.


METHODS
Two hundred and thirty-nine patients with clinical Stage T1 or T2 but surgically node-negative prostate cancer were treated. Results were monitored by serial serum PSA evaluation. Positive clinical findings or a rising PSA level defined recurrent disease.


RESULTS
With a median follow-up of 45 months (range, 24-120 months), the Kaplan-Meier projected disease free survival rate was 74% at 5 years and 66% at 10 years. Overall at a 60-month minimum follow-up, 77% of patients had a PSA of 0.5 ng/ml or less. This nadir level is highly predictive of a long term disease free survival, significantly better than pretreatment PSA, grade, or clinical Stage T1 or T2.


CONCLUSIONS
The PSA-monitored disease free survival rate after combination irradiation appears comparable with that after radical prostatectomy and perhaps superior to that after external-beam radiation. This effect was achieved even though lower-than-usual doses of radiation from both sources were administered. The combination of an I-125 implant followed by external-beam radiation produces high doses within the prostate and, to a lesser extent, in the periprostatic tissue. Additive and synergistic effects from simultaneous irradiation may be responsible for these results.
Critz
F A
FA
Department of Radiation Oncology, Radiotherapy Clinics of Georgia, Decatur 30033, USA.
Tarlton
R S
RS
Holladay
D A
DA
D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy; D002277:Carcinoma / Q000097:blood* / Q000473:pathology / Q000532:radiotherapy* / Q000556:secondary; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008197:Lymph Node Excision; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000473:pathology; D009367:Neoplasm Staging; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood* / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D011882:Radiotherapy, High-Energy; D012189:Retrospective Studies; D012669:Seminal Vesicles / Q000528:radiation effects; D015996:Survival Rate
D007457:Iodine Radioisotopes; D017430:Prostate-Specific Antigen