Purpose: Within implementation of intensity-modulated radiotherapy (IMRT) in the postoperative irradiation of cervical cancer we evaluated and compared IMRT and three-dimensional conformal radiotherapy (3DCRT) dosimetric parameters for target volumes and organs at risk (OAR).
Methods: We randomized 95 patients with cervical cancer, UICC stage I-III, in groups depending of the type of external beam postoperative radiotherapy. Forty-five patients were treated with IMRT and 50 with 3DCRT. All patients underwent brachytherapy, and according to risk factors some of the patients had concomitant cisplatin chemotherapy. The study was done in a period of three years from December 2015. Analysis of dosimetric parameters for target volume coverage and OARs was performed.
Results: IMRT plans showed better conformity compared to 3DCRT plans, represented with homogenity index and conformity index, with higher maximum dose (PTV105 and D2). Both plans achieved adequate planning target volume coverage described with PTV95. Statistically significant difference between groups was found for bladder, rectum and bowel high dose regions: bladder V45 (p=0.000), rectum V40 (p=0.043) and V45 (p=0.000), bowel V45 (p=0.000), and bone marrow dosimetric parameters V20-V45; all were better in IMRT plans. Significant difference was found for volume of patient body normal tissue receiving dose of 20Gy, which was higher in IMRT.
Conclusion: IMRT is a highly conformal technique. Satisfactory target volume coverage was achieved with both techniques, with better sparing of OARs in the IMRT group. With this technique improvement, we expect better quality of life in cervical cancer patients with good prognosis.