Prognostic significance of carcinoembryonic antigen combined with carbohydrate antigen 19‐9 following neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer

Abstract

The clinical significance of carcinoembryonic antigen (CEA) combined with carbohydrate antigen 19-9 (CA19-9) in patients with rectal cancer is not well established. The aim of this study was to determine the prognostic value of these combined tumour markers in patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (nCRT). A total of 687 consecutive patients with LARC who underwent nCRT and radical surgery were analysed. Tumour characteristics, recurrence-free survival (RFS) and overall survival (OS) were compared according to the number of elevated tumour markers measured before and after nCRT. In addition, the prognostic significance of perioperative changes in the combined tumour markers was further evaluated. The RFS and OS rates decreased in a stepwise manner in association with the number of elevated pre- and post-nCRT tumour markers (all p<0.05). Multivariate analysis showed that only the number of elevated post-nCRT tumour markers was an independent prognostic factor (both p<0.05). For 311 patients with elevated pre-nCRT tumour markers, normalization of the tumour markers after nCRT was an independent prognostic protective factor (both p<0.05), and patients with both markers elevated post-nCRT had a 2.5- and 3.7-fold increased risk of recurrence and death, respectively (p<0.05). Furthermore, normalization of post-nCRT tumour markers after surgery was also closely related to an improved prognosis. This combination of post-nCRT tumour markers can accurately predict the long-term survival of patients with LARC treated with nCRT and curative resection, and normalization of the combined tumour markers after either nCRT or surgery was associated with better survival.