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Small bowel toxicity in pelvic radiotherapy for postoperative gynecological cancer: Comparison between conformal radiotherapy and intensity modulated radiotherapy
Author(s) -
Ray Amitabh,
Sarkar Biplab
Publication year - 2013
Publication title -
asia‐pacific journal of clinical oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 29
eISSN - 1743-7563
pISSN - 1743-7555
DOI - 10.1111/ajco.12049
Subject(s) - medicine , radiation therapy , contouring , pelvis , radiology , acute toxicity , toxicity , nuclear medicine , engineering drawing , engineering
Abstract Aims To compare the dosimetric advantages of pelvic intensity modulated radiotherapy ( IMRT) with three‐dimensional conformal radiotherapy ( 3D CRT) in small bowel dose reduction and dosimetrically correlate the clinical benefit, if any. Methods This retrospective study included 60 patients with gynecological cancers treated postoperatively with radiotherapy to the whole pelvis. Radiation Therapy Oncology Group ( RTOG) contouring guidelines were used for contouring the pelvic nodal stations. All plans were generated using P lato S unrise treatment planning system. The RTOG acute morbidity scoring criteria were used to define acute small bowel toxicity in our patients. Treatment was delivered using the E lekta P recise system. Patients were followed up twice weekly while on treatment. Statistical analyses ( S pearman's rho and K ruskal– W allis test) were performed using SPSS software (vers. 15). Results In all, 65% were postoperative endometrium carcinoma and 35% were postoperative cervix carcinoma patients; 34 patients were treated with IMRT and 26 patients underwent 3D CRT . In all, 28 patients experienced ≥ grade 2 small bowel toxicity (eight in the IMRT group). IMRT was able to significantly reduce the dose to bowel for doses above 30 Gy . Small bowel toxicity showed no correlation with doses below 30 Gy . The volume of the small bowel receiving more than 35 Gy of radiation was a significant predictor of the need for medication to control diarrhea during radiotherapy. Conclusion Use of IMRT resulted in lower doses to the small bowel, resulting in lesser toxicity, and translated to the better tolerability of pelvic radiotherapy.