Clinical application of the Contoura carbon fiber belly board in patients with rectal cancer undergoing postoperative radiotherapy / 肿瘤

ABSTRACT

Objective:To evaluate the protection of small bowel and bladder by Contoura carbon fiber belly board in patients with rectal cancer undergoing postoperative radiotherapy and the position deviation during radiotherapy. Methods: This study enrolled 45 consecutive patients with rectal cancer who had undergone prior surgery. Twenty patients who applied the belly board were defined as group A, and the other 25 patients were defined as group B. All the patients received threE-dimensional conformal radiation therapy(3D-CRT), and the prescriptive radiation dosage of 95% of planning target volume (PTV) was 50 Gy/25 times. Patients in group A underwent two sets of CT scans as follows group A1, prone alone; group A2, prone with the use of the belly board. The radiation dosage and radiated volume in PTV, small bowel, and bladder were observed by dosE-volume histograms. Ten patients were selected randomly from group A and group B, respectively. Their position deviation during radiotherapy was measured by double exposure field verification system. The acute radiation reactions of all patients were observed and recorded during radiotherapy. Results: No significant difference was found in the total PTV and total volume of small bowel and bladder and mean irradiation dosage to PTV between groups A1 and A2. The mean irradiation dosage to the small bowel and bladder, the volume of small bowel irradiated at 10%-100% dose levels, and the volume of bladder irradiated at 30%-100% dose levels, were significantly decreased in group A2. The difference was significant. Compared with group B, the right-left and superior-inferior position deviations were significantly reduced in group A. The difference was significant (P<0.05). The anterior-posterior position deviation was also reduced, but the difference was not significant (P=0.705). The incidence of grade 3 or more adverse reactions were 15% (3/20) in group A and no patient broke off or stopped treatment; the incidence of grade 3 or more adverse reactions was 24% (6/25) in group B, and two patients broke off the treatment because of severe adverse reaction. One patient terminated the treatment. Conclusions: The Contoura carbon fiber belly board can reduce the irradiation dosage and volume of small bowel and bladder in patients with rectal cancer undergoing postoperative radiotherapy. The position deviation has better reproducibility and the acute radiation reactions are tolerable. It is worthy of application in clinic.