CANCER-EMBRYONIC ANTIGEN IN PREDICTING THERAPEUTIC TUMOR PATHOMORPHISM AFTER NEOADJUVANT CHEMORADIOTHERAPY IN PATIENTS WITH RECTAL CANCER

Abstract

The purpose of the study was to evaluate the prognostic significance of carcinoerembryonic antigen in patients with rectal cancer and correlate its baseline with the degree of therapeutic pathomorphosis after neoadjuvant chemoradiotherapy.Materials and methods. An estimate of the informative value of carcinoerembryonic antigen (CEA) indices in 179 patients with colorectal cancer determined before and after preoperative chemoradiotherapy (CRT) in SOD 50 Gy.Results. Analysis of the results presented in the study showed that in all patients, CRT caused a significant decrease in the level of CEA (–71%) 10 weeks after its end (p < 0.001). In the course of the pathomorphological study, after the neoadjuvant treatment, the first degree of tumor pathomorphism was recorded in 4.5% of patients, II – 38.5%, III – 45%, IV – 12% (the degree of pathomorphosis is not related to the clinical stage and the degree of differentiation of colorectal cancer). It was revealed that patients with III and IV degrees of therapeutic pathomorphosis initially had a CEA level lower, in comparison with patients with grade I-II. Clinical progression of the disease is diagnosed in 24% of cases (43/179). It was noted that in patients with the IV degree of therapeutic pathomorphism of the tumor, no recurrence of the rectal cancer was detected in either case.Conclusion. The results of the study showed that the problem of individual prediction of the effectiveness of combined treatment of the rectal cancer remains very relevant, rather complicated and yet not completely solved. However, it can be assumed that the use of such an indicator as CEA in monitoring patients after the treatment, can serve as a criterion for the sensitivity of colorectal cancer to CRT. Initially low antigen level can be considered as a positive factor of tumor response to ongoing treatment and disease-free survival of patients with locally advanced rectal cancer.