Objective: To evaluate the risk factors of patients with locally advanced cervical cancer (LACC) undergoing radical radiotherapy (with or without concurrent chemotherapy) and to assess the prognostic value of tumor volume regression (TVR) based on magnetic resonance imaging (MRI) in different risk groups. Methods: A retrospective analysis was performed on 176 individuals diagnosed with stage IIA-IVA cervical cancer (CC) who underwent radical intensity-modulated radiotherapy in our center between January 2012 and December 2020. The tumor volume before radiotherapy (TVp) and before brachytherapy (TVmid) were evaluated based on three-dimensional MRI images, TVR = (TVp -TVmid)/TVp×100%. Kaplan-Meier curves were used to assess patient’s overall survival (OS) and progression-free survival (PFS). Prognostic factors were identified using Cox proportional hazards models. Results: For the entire cohort, patients with TVR ≥ 94% had better 5-year OS (82.7% vs 49.8%, p<0.001) and 5-year PFS (82.5% vs 51.1%, p<0.001) compared to TVR < 94%. Patients with TVR ≥ 94% were more likely to receive concurrent chemoradiotherapy (CCRT) than those with TVR < 94% (70.1% vs 40.5%, p<0.05). Among patients undergoing CCRT, those with a TVR ≥ 94% had a better prognosis than those with a TVR < 94%. However, among patients who received RT alone, those with TVR ≥ 94% had better PFS but no statistically significant difference in OS. Likewise, among patients with CYFRA21-1 < 7.7 ng/ml, patients with TVR ≥ 94% had a better prognosis. However, TVR was not a prognostic factor in patients with CYFRA21-1 ≥ 7.7 ng/ml. Both CYFRA21-1 (OS, PFS interaction, p<0.001) and FIGO stage (PFS interaction, p=0.035) were found to significantly impact predictive effects of TVR. Conclusion: In LACC patients with CRYFA21-1 < 7.7 ng/ml who received CCRT, TVR was an important prognostic factor. However, in patients with CRYFA21-1 ≥7.7 ng/ml who received RT alone, the prognostic value of TVR needs to be further explored.