Intensity Modulated Versus 3D-Conformal Radiotherapy in the Treatment of Locally Advanced Cervical Cancer: a Dosimetric study

Abstract

Background and Aim: Three dimensional conformal radiotherapy (3D-CRT) is considered the standard technique used in cervical cancer. However, toxicity is still a concern. The aim of this study was to compare 3D-CRT with intensity modulated radiotherapy (IMRT) as a way to reduce toxicity. Material and Methods: Thirty patients with confirmed diagnosis of cervical cancer stage IIB-IVA treated with concurrent chemo-radiation using 3D-CRT were re-planned using IMRT. Analysis was done for target coverage, organ at risk, as well as dose homogeneity. Planning was done on Xio-Elekta planning system. Results: D 95 % was 42.7Gy for 3D-CRT plans versus 41Gy for IMRT plans and V40 for the rectum, bladder and small bowel was significantly less for IMRT. For the femoral heads: V30 was 59.4 % with IMRT versus 96 % with 3D-CRT. V10 of the pelvic bone marrow was significantly less with 3D-CRT than IMRT; however V20 was better for IMRT plans. In terms of overall treatment time, IMRT calculated treatment time is longer, with mean integral monitor unit (IMU) of 1177.01 compared to 144.30 with 3D-CRT. Conclusion: IMRT for locally advanced cervical cancer can reduce the dose to risk structures without compromising tumour coverage.