Use of expanders for bowel protection in pediatric pelvic tumor radiotherapy – 15years tolerance results

Publication date: Available online 14 December 2017
Source:Practical Radiation Oncology
Author(s): F. Missohou
RationaleBowel is often the dose-limiting organ in curative pelvic irradiation due to radiation enteritis when dose exceeding 40–45Gy. To limit radiation enteritis, a silicone tissue-expander prothesis (STEP) connected with a subcutaneous self-sealing valve was prospectively used in children undergoing pelvic or abdominal radiotherapy. This study reports the 15years long-term outcomes of this prospective series.Methods and MaterialsBetween 1987 and 2008, 29 children from 3 Paris institutions received pelvic radiotherapy after surgical placement of a STEP in the pelvis. The median prescribed dose was 50.4Gy [44.1–55Gy], using 5 daily fractions per week of 1.8Gy, except for 1 patient receiving 4 fractions of 2.5Gy per week. The median treatment duration was 40days [29–49days]. After 2000, CT-conformal 3D radiotherapy was used and 12 patients had CT-simulation. Four had CT before and after insertion of the STEP, enabling us to compare pre and post prosthesis insertion bowel dose-volume histograms. Acute and late toxicities were captured using the RTOG or the NCI-CTCAE 4.0 scale.ResultsNo patient experienced significant perioperative complications. Pre and post STEP insertion small bowel dose-volume histograms (DVH) show significant reductions in small bowel: 51%, 45% and 64% respectively in V10, V15and V40 (Vx=irradiated volume by x Gy). Twenty five patients (86%) completed their radiotherapy with none or minimal small bowel toxicity. One patient also treated with neutrons developed delayed Grade 4 toxicities. The 15years complication free survival for those surviving was 70.3%.ConclusionWe report the long-term follow-up of STEP prosthesis insertion in children to reduce the small bowel volume in the radiation field. The acute and long-term tolerances were excellent. The STEP reduced the bowel dose over 40Gy by 64%.



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