Predictive value of serum carcinoembryonic antigen level in efficacy and prognosis for patients with rectal cancer following preoperative radiochemotherapy

Abstract

To examine the association of preoperative carcinoembryonic antigen (CEA) level with the efficacy of neoadjuvant radiochemotherapy and postoperative metastasis and relapse in patients with rectal cancer. Between January 2011 and January 2014, 325 patients with local advanced rectal cancer underwent preoperative radiochemotherapy and radical operation in Department of Colorectal Cancer Surgery, Beijing University Cancer Hospital, including 194 males and 131 females. According to preoperative MRI, all the patients suffered from clinical T3-4 tumors or positive lymph nodes. Their Zubrod-ECOG-WHO score was 0-1. These patients received preoperative intensity modulated radiotherapy which consisted of 50.6 Gy in 22 fractions (IMRT GTV 50.6 Gy/CTV 41.8 Gy/22 f) with capecitabine(825 mg/m2, twice per day) as radiosensitizer. According to the preoperative serum CEA level, patients were divided into high group (125 cases) and normal group (200 cases). In high group, serum CEA level decreased into normal range in 60 patients (high-normal group) after radiochemotherapy, while it was still in high level in other 65 patients (high-high group). The differences in sensitivity to radiochemotherapy and 3-year disease free survival (DFS) of these patients were both evaluated. In high group and normal group, the complete response rates were 18.4% (23/125) and 17.5% (35/200) (χ2=0.319, P=0.660); the percentages of tumor regression grade(TRG) 0-1 patients were 68.0%(85/125) and 67.5%(135/200)(χ2=0.009, P=0.925); the T downstage rates were 63.2%(79/125) and 70.0%(140/200)(χ2=1.266, P=0.274), respectively, whose differences were all not significant. The 3-year DFS rate in high group was 62.4%, which was significantly lower than 93.5% in normal group (χ2=53.147, P=0.000). There were 65 patients in high-high group, accounting for 52% (65/125) of high group. Among these 65 patients, 44(67.7%) presented recurrence and metastasis within 3 years and the 3-year DFS was 32.3%, which was much lower than 95.0% of 60 patients in high-normal group(χ2=182.085, P=0.000). Preoperative serum CEA level may not be used to predict tumor response of rectal cancer patients who receive preoperative radiochemotherapy. However, the prognosis of patients with high CEA level is worse. Recurrence and metastasis are more likely to occur in patients with high CEA level after radiochemotherapy.