Objective:This work is aimed to investigate treatment planning strategies to optimally combine stereotactic body radiation therapy (SBRT) with intracavitary brachytherapy (ICBT) for the treatment of locally advanced cervical cancer.Methods: Fourteen patients (stage ⅡB-ⅢB) previously treated with combined SBRT and ICBT were randomly selected for this retrospective study.All patients were CT-and MR-scanned with a ring applicator in situ.HR-CTV and OARs were contoured according to fused CT and MR images.Several ICBT plans were generated for each patient based on different dose prescription points, and then a matching SBRT plan was generated for each ICBT plan.The dose distribution of each composite plan was analyzed with a focus on the doses received by 90% and 100% of the target volume (D90 and D1100), the target volume receiving 100% of the prescription dose (V100%), and the doses received by 2cc and 40% of the OARs (D2cc and D40).Results: As the distance between the prescription point and the tandem, d, varied between 1.0 and 1.8cm, the D90, D100 and V100% for the target, and D2cc and D40 for the bladder an rectum approached their optimal values with the d value between 1.0 and 1.3cm.Conclusions: When designing a combined ICBT+SBRT plan, one shall measure the size of the cervix and set the prescription isodose line 1.0~1.3cm away from the tandem for the ICBT plan first and then optimize the SBRT plan based on the ICBT dose distribution to achieve the best target coverage and critical structure sparin.