Effect of full-course concurrent dose-escalated intensity-modulated radiotherapy combined with S-1 on serum CA19-9 and CEA in patients with esophageal cancer

WANG Dandan; SONG Guanghui; LIU Chang

doi:10.3969/j.issn.1002-7386.2026.01.007

Abstract：Objective To evaluate the effect of adding S-1(tegafur/gimeracil/oteracil)to full-course concurrent dose-escalated intensity-modulated radiotherapy(IMRT)on the serum carbohydrate antigen 19-9(CA19-9)and carcinoembryonic antigen(CEA)levels in patients with esophageal cancer.Methods In this randomized study,106 patients treated between October 2020 and April 2024 were assigned to receive either full-course concurrent doseescalated IMRT alone(control;n=53)or the same IMRT regimen plus concurrent S-1(study;n=53).Dosimetric parameters for organs at risk(cardiac V30,maximum spinal cord dose,and mean doses to the right and left lungs)were recorded during IMRT.Postoperative gastrointestinal function was assessed using a hospital-developed gastrointestinal dysfunction scale.Laboratory indices included white blood cell(WBC),hemoglobin(HGB),platelet(PLT),alanine aminotransferase(ALT),aspartate aminotransferase(AST),ALT/AST ratio,and tumor markers CA19-9 and CEA.Overall response rate(ORR)and adverse events were compared between groups.Results Compared with IMRT alone,IMRT plus S-1 was associated with lower cardiac V30,maximum spinal cord dose,and reduced mean lung doses bilaterally(all P<0.05).Scores for abdominal pain,upper abdominal distension,and nausea/vomiting were significantly lower(P<0.05).WBC,HGB,PLT,CA19-9,and CEA levels significantly decreased,whereas ALT,AST,and the ALT/AST ratio significantly increased(all P<0.05).The ORR was higher in the combination group(P<0.05).Although adverse events were numerically fewer with combination therapy,the difference was not statistically significant(P>0.05).Conclusion In patients with esophageal cancer,adding S-1 to full-course concurrent doseescalated IMRT was associated with more favorable dosimetric parameters to organs at risk,improved symptom control,decreases in CA19-9 and CEA,and higher response rates,without a significant increase in toxicity.