Prognostic Significance of Lymph Node Metastases in Patients with High-Grade Appendiceal Cancer

Abstract

In treating high-grade appendiceal cancer, appropriate patient selection for cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) is essential. The effect of lymph node (LN) status on survival is not clear. We hypothesize that LN metastases negatively affect long-term survival. Retrospective analysis of peritoneal mucinous carcinomatosis (PMCA) patients from a prospective database was conducted. Using Kaplan-Meier survival curves and Cox proportional hazards ratio analysis, the effect of LN status, completeness of cytoreduction (CC), and peritoneal cancer index (PCI) was studied. Of 134 patients with appendiceal cancer who underwent CRS/HIPEC, 77 (57%) had PMCA. Mean follow-up was 22 (range, 3-90) months. Overall survival (OS) was 88, 56, and 40% for 1, 3, and 5-year, respectively. Thirty-four patients (44%) had LN metastases, 23 of whom (68%) had CC, whereas in LN negative patients 35 of 43 (81%) had CC (p=0.191). PCI≥20 was seen in 23 of 34 patients (68%) with LN metastases and 29 of 43 (67%) without metastases (p=0.191). Five-year OS for patients with LN metastases was 11% compared with 76% for LN negative (p<0.001). Among patients with complete cytoreduction, 5-year OS for LN positive vs. negative was 21 and 73%, respectively (p=0.002). On multivariate regression analysis of LN status, CC score and PCI, the following hazard ratios were obtained: 3.4 (95% confidence interval (CI), 1.3-9.0), 2.6 (95% CI, 1.03-6.7), and 2.8 (95% CI, 0.8-10.4), respectively. Patient selection for CRS/HIPEC should take into consideration LN status, but it should not be a contraindication if preoperative evaluation revealed a high likelihood of complete cytoreduction.