Late toxicity and biochemical recurrence after external-beam radiotherapy combined with permanent-source prostate brachytherapy: analysis of Radiation Therapy Oncology Group study 0019.
BACKGROUND
The combination of external-beam radiotherapy and brachytherapy is used commonly to treat men with prostate cancer. In this analysis, the authors examined the rate of biochemical recurrence (BR) and late grade > or =3 genitourinary (GU) and gastrointestinal (GI) toxicity after treatment with external-beam radiotherapy and brachytherapy in a multiinstitutional, cooperative group setting.


METHODS
All eligible patients received external-beam radiotherapy (45 Gray [Gy] in 25 fractions) followed 2 to 6 weeks later by an interstitial implant using iodine-125 to deliver an additional 108 Gy. BR was defined in 2 ways: according to the American Society for Therapeutic Radiology and Oncology (ASTRO) Consensus Definition (ACD) and according to the Phoenix definition (PD) (prostate-specific antigen nadir +2 ng/mL). The Radiation Therapy Oncology Group(RTOG)/European Organization for Research and Treatment of Cancer late radiation morbidity scoring system was used to grade all toxicity.


RESULTS
One hundred thirty-eight patients were enrolled, and 130 were eligible for the current analysis. The median follow-up for surviving patients was 49 months (range, 20-60 months). The 48-month estimate of late grade > or =3 GU/GI toxicity was 15% (95% confidence interval [95% CI], 8-21%), and the 48-month estimate of BR was 19% (95% CI, 12-26%) and 14% (95% CI, 8-20%) according to the ACD and PD, respectively.


CONCLUSIONS
The morbidity observed in this multiinstitutional, cooperative group study was slightly higher than that reported in recent RTOG studies using brachytherapy alone or high-dose external-beam radiotherapy. The BR rate observed in this report was similar to that observed with high-dose external-beam radiotherapy alone in similar patients.
Lee
W Robert
WR
Department of Radiation Oncology, Duke University School of Medicine, Durham, North Carolina 27710, USA. lee00255@mc.duke.edu
Bae
Kyoungwha
K
Lawton
Colleen
C
Gillin
Michael
M
Morton
Gerard
G
Firat
Selim
S
Baikadi
Madhava
M
Kuettel
Michael
M
Greven
Kathryn
K
Sandler
Howard
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects*; D003131:Combined Modality Therapy; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D011471:Prostatic Neoplasms / Q000401:mortality / Q000532:radiotherapy*; D011878:Radiotherapy / Q000009:adverse effects*; D013997:Time Factors; D016896:Treatment Outcome