Abstract: Objective To investigate the effect of sequential chemoradiotherapy after surgery on survival of patients with stage I low-grade endometrial stromal sarcoma（LGESS）， and evaluate side effects. MethodsA total of 52 patients were collected from June 1995 to December 2010. Twenty-eight patients received sequential chemoradiotherapy following surgery， and 24 patients received surgery alone as control. Patients in sequential chemoradiotherapy group received 2 cycles of chemotherapy（CYVADIC， VAD or IAP regimen）， and then pelvic external radiation was applied with DT of 40-50 Gy. Two cycles of chemotherapy was followed by radiation. The survival and recurrence were evaluated， as well as side effects. ResultsThe median follow-up was 118 months（20-185 months）with the follow-up rate of 92.3％. In 52 patients， 9 cases developed recurrence， with 7 cases relapsed in control group. The 5，10year recurrencefree survival rates were 96.4％ and 91.4％ in sequential chemoradiotherapy after surgery group， higher than 75.0％ and 70.3％ in control group（P=0.035）；the 5，10year overall survival rates had no statistical difference between the two groups（P＞0.05）. All 28 patients with sequential chemoradiotherapy completed treatment. The chemotherapyrelated toxic effects were mainly gastrointestinal reactions and hematologic toxicities， and the gastrointestinal reactions were all grade 1 or 2. Thirteen patients experienced hematologic toxicities and grade 3 or 4 hematologic toxicities were observed in 5 patients， which could recovered after expectant treatment. The radiation reaction was mainly radiation proctitis and vaginitis of grade 1 or 2. No acute grade 3 or 4 radiation toxicities were observed. There was no treatment-related death. Conclusion LGESS has good prognosis, but it is with a tendency to develop late recurrence， even for stage Ⅰ patients. The main treatment is surgery. Sequential chemoradiotherapy after surgery is suggested to reduce the pelvic recurrence， and the toxic effects can be well tolerated.