Conformal high dose rate brachytherapy improves biochemical control and cause specific survival in patients with prostate cancer and poor prognostic factors.
OBJECTIVE
To improve outcome for patients with prostate cancer with poor prognostic factors higher than conventional radiation doses are required. To achieve this outcome a brachytherapy boost was given. We report the results of the first high dose rate dose-escalation brachytherapy trial.


METHODS
Between 1991 and 2000, 207 patients were prospectively enrolled in a dose escalation trial including pelvic radiotherapy and conformal high dose rate prostate brachytherapy boost. The dose was increased from 5.5 to 11.5 Gy. per implant. Patient eligibility for the study included pretreatment prostate specific antigen 10 or greater, Gleason 7 or greater or clinical stage T2b or higher. No patient received hormonal therapy. The American Society for Therapeutic Radiology and Oncology consensus panel definition of biochemical failure was applied.


RESULTS
Median patient age was 69 years. Mean followup was 4.7 years (range 0.6 to 10.4). The 5-year actuarial biochemical control rate was 74%. The 5-year biochemical control was 85% for 1 poor prognostic factor, 75% for 2 and 50% for all 3 (p = 0.001). On Cox regression multivariate analysis lower brachytherapy dose, and higher Gleason and nadir value were associated with biochemical failure. The 5-year actuarial overall survival was 92%, cause specific survival 98% and disease-free survival 68%. The 5-year actuarial rates of complications were 8% and 0% for grades 3 and 4 genitourinary, and 0.5% and 0.5% for grades 3 and 4 gastrointestinal, respectively. The 5-year actuarial impotence rate was 51%.


CONCLUSIONS
For patients with poor prognostic factors external beam radiation therapy with conformal high dose rate brachytherapy boost improved biochemical control, resulting in a high cause specific survival rate with low toxicity. Another important advantage is that the patient is not radioactive after the high dose rate implant.
Martinez
Alvaro
A
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan, USA.
Gonzalez
Jose
J
Spencer
William
W
Gustafson
Gary
G
Kestin
Larry
L
Kearney
David
D
Vicini
Frank A
FA
D000206:Actuarial Analysis; D000230:Adenocarcinoma / Q000097:blood / Q000401:mortality / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy; D018572:Disease-Free Survival; D006801:Humans; D007496:Iridium Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000401:mortality / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D015996:Survival Rate
D007496:Iridium Radioisotopes; D017430:Prostate-Specific Antigen