宫颈癌卵巢移位术后IMRT与VMAT放疗对卵巢功能保护的剂量学评估OACSTPCD

Objective To evaluate the dosimetric advantages of intensity-modulated radiation therapy(IMRT)versus volumetric-modulated arc therapy(VMAT)in preserving ovarian function in cervical cancer patients post-oophoropexy.Methods From January 2016 to January 2022,44 patients with cervical squamous cell carcinoma who underwent oophoropexy and required adjuvant radiotherapy were selected from Huai'an Second People's Hospital.Patients were divided into IMRT and VMAT groups,with 22 cases in each group.The IMRT group received 9-field coplanar irradiation,while the VMAT group received dual-arc coplanar irradiation.The dosimetric differences and impact on ovarian function between the two radiotherapy modalities were compared,and the relationship between the location of the relocated ovaries and ovarian dose was analyzed.Results IMRT showed superior parameters for the planning target volume(PTV)including D2％,D98％,conformity index(CI),and homogeneity index(HI)compared to VMAT.In terms of ovarian protection,IMRT had lower mean ovarian dose(Dmean 5.21±1.34 Gy),maximum ovarian dose(Dmax 8.28±2.65 Gy),V5(50.63±30.23),and V7(16.11±22.68)compared to VMAT(P＜0.05).For organ at risk(OAR)protection,the change in estradiol(E2)levels pre-and post-treatment was higher in the IMRT group than in the VMAT group(P＜0.05),while the changes in luteinizing hormone(LH)and follicle-stimulating hormone(FSH)levels were lower in the IMRT group(P＜0.05).No significant differences were observed in the changes in Dmean of the femoral heads and D2％of the rectum between the two groups(P＞0.05).Univariate analysis revealed significant differences in the lateral distance from the ovarian central plane to the ipsilateral PTV between the IMRT and VMAT groups(P＜0.05).In the IMRT group,the mean ovarian dose was positively correlated with the vertical distance from the ovarian central plane to the iliac crest(r=0.667,P＜0.05)and negatively correlated with the minimum distance to the PTV and lateral distance to the ipsilateral PTV(r=-0.824 and-0.907,respectively,both P＜0.05),as well as ovarian volume(r=-0.370,P＜0.05).In the VMAT group,the mean ovarian dose was positively correlated with the vertical distance from the ovarian central plane to the iliac crest(r=0.624,P＜0.05)and negatively correlated with the minimum distance to the PTV and lateral distance to the ipsilateral PTV(r=-0.804 and-0.885,respectively,both P＜0.05),as well as ovarian volume(r=-0.340,P＜0.05).Conclusion Dosimetric comparison indicates that IMRT provides better protection for ovarian function in cervical cancer patients post-oophoropexy.The lateral distance from the ovarian central plane to the ipsilateral PTV can predict the ovarian dose.