Prognostic Impact of a Decrease in Serum Carbohydrate Antigen 19-9 Levels After Preoperative Therapy for 4 Months or More for Borderline Resectable Pancreatic Cancer Abutting Major Arteries

<b>Background:</b> This study aimed to identify the prognostic factors after pancreatectomy for borderline resectable pancreatic cancer abutting major arteries (BR-A).<b>Methods:</b> We retrospectively investigated relationship between preoperative and intraoperative variables and overall survival (OS) through univariate and multivariate analyses. The cut-off points of preoperative therapy duration and response rates of serum carbohydrate antigen 19-9 (CA19-9) levels after preoperative therapy were determined through a minimum <i>P</i>-value approach using the log-rank test for OS. Overall survival was compared among patients stratified according to the independent prognostic factors and the presence or absence of pancreatectomy.<b>Results:</b> After pretreatment, 17 patients underwent pancreatectomy and four patients continued chemotherapy without surgery. Multivariate analysis in 17 resected BR-A patients demonstrated decreased serum CA19-9 levels and preoperative therapy duration of ≥4 months were the independent prognostic factors [hazard ratio (HR) 0.01; <i>P</i> = 0.002, HR 0.13; <i>P</i> = 0.02]. Patients who underwent surgery with decreased serum CA19-9 levels after preoperative therapy of ≥4 months had a significantly better prognosis than those without one or both of independent prognostic factors and those who did not undergo surgery (median survival time: not estimated, 23.3 months, 10.5 months, and 10.8 months; <i>P</i> = 0.02, <i>P</i> = 0.004, and <i>P</i> = 0.001, respectively). Furthermore, the prognosis did not significantly differ between the patients who underwent surgery without meeting either one or both criteria and those without surgery.<b>Conclusions:</b> Preoperative therapy duration of ≥4 months and decreased serum CA19-9 levels are independent prognostic factors among BR-A patients.