Toxicity of tomotherapy-based simultaneous integrated boost in whole-pelvis radiation for prostate cancer.
PURPOSE
The validity of tomotherapy-based simultaneous integrated boost (TOMOSIB) was assessed in terms of acute intestinal/urinary toxicity by comparing with 3-dimensional conformal radiotherapy (3DCRT) in cases of whole-pelvis radiation therapy (WPRT) for prostate cancer.


MATERIALS AND METHODS
Thirty-eight consecutive patients who underwent curative WPRT were retrospectively reviewed. Twenty six (68.4%) received 3DCRT and the others (31.6%) were treated with TOMOSIB. A local boost to the prostate circumferential area was added to WPRT sequentially for 3DCRT and concomitantly for TOMOSIB. The total median prostate or prostatic bed dose was 64.8 Gy including median 45.0 Gy of WPRT. Acute toxicities were assessed according to RTOG criteria.


RESULTS
Overall intestinal toxicity was lower in TOMOSIB group than 3DCRT group (p=0.008). When it was divided into rectum and non-rectum intestine (NRI), TOMOSIB showed borderline superiority only in NRI toxicity (p=0.047). For the urinary toxicity, there was no significant difference between two groups (p=0.796). On dosimetric analysis for the rectum and bladder, dose delivered to 80% (p<0.001) and volume receiving 25-40 Gy (p<0.001) were remarkably higher in 3DCRT. For the NRI, only maximum dose showed significant results between two groups (p<0.001).


CONCLUSION
Intestinal toxicity should be verified with more detailed anatomic categorization such as rectum and NRI. TOMOSIB could not reduce urinary toxicity because of inevitably high dose exposure to the prostatic urethra. Current dosimetry system did not properly reflect intestinal/urinary toxicity, and suitable dosimetric guidelines are needed in TOMOSIB.
['You|Sei Hwan|SH|', 'Lee|Jong Young|JY|', 'Lee|Chang Geol|CG|']
D000230:Adenocarcinoma D000368:Aged D006801:Humans D007421:Intestine, Small D008297:Male D008875:Middle Aged D010388:Pelvis D011471:Prostatic Neoplasms D011832:Radiation Injuries D011879:Radiotherapy Dosage D050397:Radiotherapy, Intensity-Modulated D012007:Rectum D012189:Retrospective Studies D001743:Urinary Bladder
radiation prostate cancer Acute toxicity helical tomotherapy