Dosimetric and toxicity comparison between prone and supine position IMRT for endometrial cancer.
OBJECTIVE
To determine the dosimetric and toxicity differences between prone and supine position intensity-modulate radiotherapy in endometrial cancer patients treated with adjuvant radiotherapy.


METHODS
Forty-seven consecutive endometrial cancer patients treated with adjuvant RT were analyzed. Of these, 21 were treated in prone position and 26 in the supine position. Dose-volume histograms for normal tissue structures and targets were compared between the two groups. Acute and chronic toxicity were also compared between the cohorts.


RESULTS
The percentage of volume receiving 10, 20, 30, 40, 45, and 50 Gy for small bowel was 89.5%, 69%, 33%, 12.2%, 5%, and 0% in the prone group and 87.5%, 62.7%, 26.4%, 8%, 4.3%, and 0% in the supine group, respectively. The difference was not statistically significant. The dose-volume histograms for bladder and rectum were also comparable, except for a slightly greater percentage of volume receiving 10 Gy (1.5%) and 20 Gy (5%) for the rectum in the prone group. Acute small bowel toxicities were Grade 1 in 7 patients and Grade 2 in 14 patients in the prone group vs. Grade 1 in 6 patients and Grade 2 in 19 patients in the supine group. Chronic toxicity was Grade 1 in 7 patients and Grade 3 in 1 patient in the prone group and Grade 1 in 5 patients in the supine group.


CONCLUSIONS
These preliminary results suggest that no difference exists in the dose to the normal tissue and toxicity between prone and supine intensity-modulated radiotherapy for endometrial cancer. Longer follow-up and more outcome studies are needed to determine whether any differences exist between the two approaches.
Beriwal
Sushil
S
Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA. beriwals@upmc.edu
Jain
Sheena K
SK
Heron
Dwight E
DE
de Andrade
Regiane S
RS
Lin
Chyonghiou J
CJ
Kim
Hayeon
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016889:Endometrial Neoplasms / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D007421:Intestine, Small / Q000528:radiation effects; D008875:Middle Aged; D016684:Prone Position; D011832:Radiation Injuries / Q000517:prevention & control; D011879:Radiotherapy Dosage; D018714:Radiotherapy, Adjuvant; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012007:Rectum / Q000528:radiation effects; D018709:Statistics, Nonparametric; D016683:Supine Position; D001743:Urinary Bladder / Q000528:radiation effects