The impact of lymph node ratio on survival in gallbladder cancer: a national cancer database analysis

Background: The study aimed to investigate the impact of lymph node ratio (LNR) on survival in patients with resectable gallbladder adenocarcinoma. Methods: We retrospectively analyzed the National Cancer Database from 2004 to 2020. We included patients with gallbladder adenocarcinoma who had undergone resection of the primary site as well as adequate lymphadenectomy. Exclusions comprised patients with distant metastasis and missing key data. LNR was calculated as a proportion of positive lymph nodes (LNs) to examined LNs. Results: Patients were stratified into LNR groups: LNR0 -343 patients (55%); 168 (26.9%) patients with LNR <30%; and 113 (18.1%) with LNR > 30%. The mean age was 67.3 +/- 10.7 years, with 71.6% being female and 75.8% identifying as white. The mean overall survival (OS) was 52.8 months for the LNR0 group, 36.3 months for LNR <30%, and 27 months for LNR > 30% (p < 0.001). The difference in survival was significant when adjusted for adjuvant chemotherapy status and surgical margins using Cox regression - HR 3.2 (2.4-4.5 95% CI) for LNR <30% and HR 4.9 (3.5-6.8 95% CI) for LNR > 30%. Conclusion: The study suggests that LNR is a valuable prognostic factor for resectable gallbladder cancer patients and could potentially guide treatment decisions.