A comparison of acute and chronic toxicity for men with low-risk prostate cancer treated with intensity-modulated radiation therapy or (125)I permanent implant.
OBJECTIVE
To compare the toxicity and biochemical outcomes of intensity-modulated radiation therapy (IMRT) and (125)I transperineal permanent prostate seed implant ((125)I) for patients with low-risk prostate cancer.


METHODS
Between 1998 and 2004, a total of 374 low-risk patients (prostate-specific antigen < 10 ng/ml, T1c-T2b, Gleason score of 6 or less, and no neoadjuvant hormones) were treated at Fox Chase Cancer Center (216 IMRT and 158 (125)I patients). Median follow-up was 43 months for IMRT and 48 months for (125)I. The IMRT prescription dose ranged from 74-78 Gy, and (125)I prescription was 145 Gy. Acute and late gastrointestinal (GI) and genitourinary (GU) toxicity was recorded by using a modified Radiation Therapy Oncology Group scale. Freedom from biochemical failure was defined by using the Phoenix definition (prostate-specific antigen nadir + 2.0 ng/ml).


RESULTS
Patients treated by using IMRT were more likely to be older and have a higher baseline American Urological Association symptom index score, history of previous transurethral resection of the prostate, and larger prostate volumes. On multivariate analysis, IMRT was an independent predictor of lower acute and late Grade 2 or higher GU toxicity and late Grade 2 or higher GI toxicity. Three-year actuarial estimates of late Grade 2 or higher toxicity were 2.4% for GI and 3.5% for GU by using IMRT compared with 7.7% for GI and 19.2% for GU for (125)I, respectively. Four-year actuarial estimates of freedom from biochemical failure were 99.5% for IMRT and 93.5% for (125)I (p = 0.09).


CONCLUSIONS
The IMRT and (125)I produce similar outcomes, although IMRT appears to have less acute and late toxicity.
Eade
Thomas N
TN
Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111-2497, USA.
Horwitz
Eric M
EM
Ruth
Karen
K
Buyyounouski
Mark K
MK
D'Ambrosio
David J
DJ
Feigenberg
Steven J
SJ
Chen
David Y T
DY
Pollack
Alan
A
D000208:Acute Disease; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects*; D002908:Chronic Disease; D005500:Follow-Up Studies; D041981:Gastrointestinal Tract / Q000528:radiation effects; D006801:Humans; D007457:Iodine Radioisotopes / Q000528:radiation effects* / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000473:pathology*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D014566:Urogenital System / Q000528:radiation effects
D007457:Iodine Radioisotopes; D017430:Prostate-Specific Antigen