ObjectivesThis study aimed to investigate the influence of baseline sarcopenia and changes in body composition on survival during cervical cancer treatment. MethodsPatients diagnosed with stage IB1-IVB cervical cancer who underwent primary concurrent chemoradiation therapy (CCRT) between 2002 and 2022 were included. The exclusion criteria were prior radical hysterectomy, lack of pretreatment computed tomography (CT) imaging, or significant comorbidities. An artificial intelligence-based automatic segmentation program assessed body composition by analyzing CT images, defining L3 sarcopenia (L3 skeletal muscle index [SMI] <39cm2/m2) and volumetric sarcopenia (volumetric SMI <180.4 cm3/m3). Comparative and multivariate analyses identified the prognostic factors. The impact of body component changes during CCRT was explored. ResultsAmong 347 patients, there were 125 recurrences and 59 deaths (median follow-up, 50.5 months). Seven patients were excluded from the volumetric sarcopenia analysis because of incomplete baseline CT data, and 175 patients were included in the analysis of body composition changes. Patients with L3 sarcopenia had a lower 5-year progression-free survival (PFS) rate (55.6% vs. 66.2%, p = 0.027), while those with volumetric sarcopenia showed a poorer 5-year overall survival rate (76.5% vs. 85.1%, p = 0.036). Patients with total fat loss during CCRT had a worse 5-year PFS rate than those with total fat gain (61.9% vs. 73.8%, p = 0.029). Multivariate analyses revealed that total fat loss (adjusted hazard ratio [aHR], 2.172; 95% confidence interval [CI], 1.066–4.424; p = 0.033) was a significant factor for recurrence, whereas L3 sarcopenia was not. Volumetric sarcopenia increased the risk of death by 1.75-fold (aHR, 1.750; 95% CI, 1.012–3.025; p = 0.045). ConclusionsAmong patients with cervical cancer undergoing CCRT, initial volumetric sarcopenia and fat loss during treatment are survival risk factors. These findings suggest the potential importance of personalized supportive care, including tailored nutrition and exercise interventions.