Predictors of occult metastases in potentially Resectable pancreatic ductal adenocarcinoma

Background

Patients with resectable (R) or borderline resectable (BR) pancreatic ductal adenocarcinoma (PDAC) sometimes show unexpected liver, peritoneal, and para-aortic lymph node metastases intraoperatively. Despite radical pancreatectomy, a nonnegligible number of patients relapse within 6 months after surgery. The aim of this study was to identify the preoperative predictors of occult metastases (OM), defined as intraoperative distant metastases or within 6 months after pancreatectomy.

Materials and methods

This study included patients with R and BR PDAC who underwent curative-intent pancreatectomy or staging laparoscopy between 2006 and 2021. Multivariate logistic regression and Cox hazard analyses were performed to identify the preoperative predictors of OM and to assess the impact of these factors on prognosis after pancreatectomy.

Results

Of the 279 patients, OM was observed intraoperatively in 47 and postoperatively in 34. In the OM group, there were no differences in prognosis between patients who had intraoperative metastases and recurrence within 6 months (median survival time [MST], 18.1 vs. 12.9 months), and between patients who underwent pancreatectomy and those who did not (MST, 13.9 vs. 18.1 months). Preoperative tumor size ≥22 mm (odds ratio [OR], 2.03; 95 % confidence interval [CI], 1.16–3.53; p = 0.013) and preoperative CA19–9 level ≥ 118.8 U/mL (OR, 2.64; 95 % CI, 1.22–5.73; p = 0.014) were significant predictors of OM. Additionally, positive OM predictors were strong independent prognostic factors for overall survival after pancreatectomy (hazard ratio, 2.47; 95 % CI, 1.54–3.98; p < 0.001).

Conclusion

Multidisciplinary treatment strategies should be considered for patients with predictors of OM to avoid inappropriate surgical interventions.