Do Lymph Node Metastases Matter in Appendiceal Cancer with Peritoneal Carcinomatosis? A US HIPEC Collaborative Study

Area of Science:

• Surgical Oncology
• Gastrointestinal Oncology
• Appendiceal Cancer Research

Background:

• The necessity of regional lymph node (LN) evaluation in appendiceal adenocarcinoma (AA) with peritoneal metastases remains uncertain.
• This study investigates the prognostic impact of LN metastases on survival outcomes.

Purpose of the Study:

• To assess the prognostic value of lymph node (LN) metastases in patients with appendiceal adenocarcinoma (AA).
• To determine if LN status impacts survival in patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC).

Main Methods:

• Retrospective analysis of 250 patients with AA from the US HIPEC collaborative.
• Inclusion criteria required adequate LN sampling (≥12 LNs).
• Outcomes were compared between LN-positive and LN-negative disease, with multivariate and propensity score matching analyses.

Main Results:

• LN-positive disease was independently associated with worse overall survival (OS) (HR: 2.82, p=0.01).
• Median OS was significantly lower in LN-positive patients (25.9 months vs. 91.4 months, p<0.01).
• LN status remained a significant predictor of poor OS even after propensity score matching and in patients with high PCI.

Conclusions:

• Lymph node status is a significant independent predictor of worse overall survival in appendiceal adenocarcinoma patients undergoing CRS-HIPEC, even with advanced peritoneal carcinomatosis.
• Formal lymph node evaluation should be routinely performed for patients with AA undergoing CRS-HIPEC to guide treatment and prognostication.