Volumetric modulated arc therapy versus fixed-field intensity-modulated radiotherapy in radical radiotherapy for cervical cancer

Objective To compare the advantages and disadvantages of volumetric modulated arc therapy(VMAT)and fixed-field intensity-modulated radiotherapy(f-IMRT)in radical radiotherapy for cervical cancer. Methods Clinical materials of 43 cervical cancer patients with VMAT and f-IMRT were analyzed retrospectively. Dosimetric parameters, the clinical complications and efficacy were compared between two groups. Results The conformity index(CI)of VMAT plan group was higher than that of f-IMRT plans group, and no significant differences were found in other dosimetric parameters such as maximum dose(D_max), average dose(D_mean), homogeneity index(HI)and machine tuning(MU). VMAT plan group resulted in reductions in V₃₀, V₄₀, V₅₀ of intestine, V₄₀ of rectum and V₅₀ of the bladder(P<0.05). There were significant differences between the two groups in grade Ⅰ and Ⅱ gastrointestinal side effects. Conclusion Compared with f-IMRT plan, VMAT plan has a better conformability, which can better protect normal tissues such as small intestine and bladder as well as significantly shorten treatment time, so it is a better option for external radiotherapy for cervical cancer.