Late Rectal Toxicity from Image-guided Intensity Modulated Radiotherapy for Prostate Cancer.
OBJECTIVE
Late rectal toxicity (LRT) was retrospectively evaluated in men with prostate cancer treated with image-guided intensity modulated radiotherapy (IG-IMRT).


METHODS
Between May 2008 and December 2009, 47 men with prostate adenocarcinoma were treated with IG-IMRT using in-room computed tomography (CT).


RESULTS
The median time to grade 2 LRT was 12 months (range=1-24 months). Two of 3 men who developed grade 2 LRT had received treatment for diabetes, and the other was receiving anticoagulant/antiplatelet therapy (AC therapy). Their rectal wall V70 (the volume of rectal wall receiving 70 Gy) values were 12.6%, 13.0%, and 13.3%. Univariate analysis revealed that V70 of the rectal wall was the only significant risk factor for LRT (p=0.0073).


CONCLUSIONS
No man with V70 ≤12.0% experienced grade 2 LRT. Strict rectal wall V70 ≤12% dose constraints should be considered when treating prostate cancer patients who are also receiving diabetic or AC therapy.
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Sayo
S
Maki
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan rin01291823@gmail.com.
Yoshiyuki
Y
Itoh
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Seiji
S
Kubota
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Tohru
T
Okada
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Rie
R
Nakahara
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Junji
J
Ito
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Mariko
M
Kawamura
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Takeshi
T
Kamomae
Department of Radiology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Shinji
S
Naganawa
Department of Urology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Yasushi
Y
Yoshino
Department of Urology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Momokazu
M
Gotoh
Department of Radiological Sciences, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.
Mitsuru
M
Ikeda
D000230:Adenocarcinoma / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D061089:Radiotherapy, Image-Guided; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D012007:Rectum / Q000528:radiation effects*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
IGRT; IMRT; Prostate cancer; late rectal bleeding