Introduction Some patients with locally advanced cervical cancer (LACC) cannot undergo brachytherapy (BT). Possible treatment includes two-stage external beam radiotherapy (sequential boost – SEQ) or single-stage external beam radiotherapy (simultaneous integrated boost – SIB). The goal of this paper was to carry out dosimetric and radiobiological comparison of these techniques with respect to tumour and organs-at-risk (OARs) irradiation. Methods The anatomic data of six patients with LACC were used for this study. The single-stage SIB-VMAT (25, 27 or 30 fractions) and double-stage SEQ-VMAT (25 + 6 fractions) plans were developed to deliver EQD2=50 Gy to the pelvic region and EQD2=90 Gy to the tumour. The developed plans were compared with respect to an EQD2 dose delivered to a tumour and to the OARs, expected tumour control probability and normal tissue complications probability. Results The developed SIB-VMAT and SEQ-VMAT plans had physical coverage of the CTV tumours with more than 95% of the prescribed dose delivered to more than 95% of the volume. The irradiation of the tumour for both SIB-VMAT and SEQ-VMAT has comparable EQD2 values close to 87–88 Gy. SIB-VMAT treatment plans provided lower levels of irradiation of OARs than SEQ-VMAT plans. The optimal number of fractions for SIB-VMAT was 27. Conclusion SIB-VMAT is a better treatment option for patients with LACC that are not eligible for BT. Results show that both SIB-VMAT and SEQ-VMAT allowed good coverage of the tumour and high-quality dose delivery. SIB-VMAT allowed minimising irradiation of OARs and shortening the overall treatment time by a week.
- Locally advanced cervical cancer
- Simultaneous integrated boost
- Volumetric modulated arc therapy
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Physics and Astronomy(all)