Volumetric Modulated Arc Therapy versus Fixed-Field Intensity-Modulated Radiotherapy in Radical Irradiation for Cervical Cancer without Lymphadenectasis: Dosimetric and Clinical Results.

BACKGROUND

The aim of this study was to compare the dosimetric parameters, clinical complications, and efficacy of volumetric modulated arc therapy (VMAT) and fixed-field intensity-modulated radiotherapy (f-IMRT) in radical radiotherapy for cervical cancer without lymphadenectasis.

METHODS

84 cervical cancer patients undergoing treatment with VMAT and f-IMRT were selected. Dose-volume histograms were used to evaluate the dose distribution in the planning target volume (PTV) and organs at risk. The clinical complications and efficacy were observed.

RESULTS

The homogeneity index (HI) and the conformity index (CI) of VMAT plans were both superior to the HI and CI of f-IMRT plans (p = 0.043, 0.025). VMAT plans resulted in a reduction in the V30 of the rectum and V40 of the bladder (p = 0.002). Furthermore, the monitor units (MUs) for VMAT were less than a quarter of those for f-IMRT. The treatment time for VMAT was less than a half of that for f-IMRT. Both clinical complications and efficacy showed no significant differences.

CONCLUSION

VMAT plans showed superior dose coverage of the PTV, better protection of the rectum and bladder in dosimetry, and significantly reduced MUs and treatment time compared with f-IMRT. Clinical results were similar for both plans.