Usefulness of carcinoembryonic antigen doubling time in prognosis prediction after curative resection of locally recurrent rectal cancer: A retrospective study.

INTRODUCTION Given that doubling time is an indicator of tumor growth, we assessed the usefulness of carcinoembryonic antigen doubling time (CEA-DT) in prognosis prediction after curative resection for locally recurrent rectal cancer. METHODS During January 1986 to December 2016, 33 patients with locally recurrent rectal cancer who underwent curative resection at our hospital were retrospectively reviewed. The primary endpoint was the 3-year recurrence-free survival (RFS) rate. The Kaplan-Meier method was used to compare RFS rates and evaluate univariate and multivariate analyses for factors associated with oncologic outcomes, including CEA-DT. CEA-DT was classified into two groups: the short and long CEA-DT groups. RESULTS The 3-year overall survival and RFS rates were 62.6% and 42.4%, respectively. In multivariate analyses, CEA-DT was an independent risk factor for poor RFS. The 3-year RFS rate was significantly better in the long CEA-DT group than in the short CEA-DT group (58.8% vs. 25.0%, p = 0.0063). CONCLUSION CEA-DT is a useful prognostic factor that can be assessed before surgery for locally recurrent rectal cancer. Long CEA-DT may indicate a favorable prognosis. Contrarily, short CEA-DT is associated with poor prognosis; therefore, further treatment intervention is necessary for patients with short CEA-DT.