Matched-pair analysis of conformal high-dose-rate brachytherapy boost versus external-beam radiation therapy alone for locally advanced prostate cancer.
OBJECTIVE
We performed a matched-pair analysis to compare our institution's experience in treating locally advanced prostate cancer with external-beam radiation therapy (EBRT) alone to EBRT in combination with conformal interstitial high-dose-rate (HDR) brachytherapy boosts (EBRT + HDR).


METHODS
From 1991 to 1998, 161 patients with locally advanced prostate cancer were prospectively treated with EBRT + HDR at William Beaumont Hospital, Royal Oak, Michigan. Patients with any of the following characteristics were eligible for study entry: pretreatment prostate-specific antigen (PSA) level of >/= 10.0 ng/mL, Gleason score >/= 7, or clinical stage T2b to T3c. Pelvic EBRT (46.0 Gy) was supplemented with three (1991 through 1995) or two (1995 through 1998) ultrasound-guided transperineal interstitial iridium-192 HDR implants. The brachytherapy dose was escalated from 5.50 to 10.50 Gy per implant. Each of the 161 EBRT + HDR patients was randomly matched with a unique EBRT-alone patient. Patients were matched according to PSA level, Gleason score, T stage, and follow-up duration. The median PSA follow-up was 2.5 years for both EBRT + HDR and EBRT alone.


RESULTS
EBRT + HDR patients demonstrated significantly lower PSA nadir levels (median, 0.4 ng/mL) compared with those receiving EBRT alone (median, 1.1 ng/mL). The 5-year biochemical control rates for EBRT + HDR versus EBRT-alone patients were 67% versus 44%, respectively (P <.001). On multivariate analyses, pretreatment PSA, Gleason score, T stage, and the use of EBRT alone were significantly associated with biochemical failure. Those patients in both treatment groups who experienced biochemical failure had a lower 5-year cause-specific survival rate than patients who were biochemically controlled (84% v 100%; P <.001).


CONCLUSIONS
Locally advanced prostate cancer patients treated with EBRT + HDR demonstrate improved biochemical control compared with those who are treated with conventional doses of EBRT alone.
Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI, USA.
L L
LL
Kestin
A A
AA
Martinez
J S
JS
Stromberg
G K
GK
Edmundson
G S
GS
Gustafson
D S
DS
Brabbins
P Y
PY
Chen
F A
FA
Vicini
D000368:Aged; D001918:Brachytherapy; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008297:Male; D016555:Matched-Pair Analysis; D011446:Prospective Studies; D017430:Prostate-Specific Antigen / Q000032:analysis; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011882:Radiotherapy, High-Energy; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome
D017430:Prostate-Specific Antigen