Prognostic Performance of Different Lymph Node Staging Systems After Curative Intent Resection for Gastric
Gaya Spolverato1, Aslam Ejaz, Yuhree Kim
1*Department of Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD †Department of Surgery, Division of Surgical Oncology, Winship Cancer Institute, Emory University, Atlanta, GA ‡Department of Surgery, Stanford University, Palo Alto, CA §Department of Surgery, Washington University School of Medicine, St. Louis, MO ¶Department of Surgery, The Ohio State University, Columbus, OH ||Department of Surgery, Division of Surgical Oncology, University of Wisconsin, Madison, WI **Department of Surgery, Wake Forest University, Winston-Salem, NC.
Objective:
To compare the prognostic performance of American Joint Committee on Cancer/International Union Against Cancer seventh N stage relative to lymph node ratio (LNR), log odds of metastatic lymph nodes (LODDS), and N score in gastric adenocarcinoma.
Background:
Metastatic disease to the regional LN basin is a strong predictor of worse long-term outcome following curative intent resection of gastric adenocarcinoma.
Methods:
A total of 804 patients who underwent surgical resection of gastric adenocarcinoma were identified from a multi-institutional database. The relative discriminative abilities of the different LN staging/scoring systems were assessed using the Akaike's Information Criterion (AIC) and the Harrell's concordance index (c statistic).
Results:
Of the 804 patients, 333 (41.4%) had no lymph node metastasis, whereas 471 (58.6%) had lymph node metastasis. Patients with ≥N1 disease had an increased risk of death (hazards ratio = 2.09, 95% confidence interval: 1.68-2.61; P < 0.001]. When assessed using categorical cutoff values, LNR had a somewhat better prognostic performance (C index: 0.630; AIC: 4321.9) than the American Joint Committee on Cancer seventh edition (C index: 0.615; AIC: 4341.9), LODDS (C index: 0.615; AIC: 4323.4), or N score (C index: 0.620; AIC: 4324.6). When LN status was modeled as a continuous variable, the LODDS staging system (C index: 0.636; AIC: 4304.0) outperformed other staging/scoring systems including the N score (C index: 0.632; AIC: 4308.4) and LNR (C index: 0.631; AIC: 4225.8). Among patients with LNR scores of 0 or 1, there was a residual heterogeneity of outcomes that was better stratified and characterized by the LODDS.
Conclusions:
When assessed as a categorical variable, LNR was the most powerful manner to stratify patients on the basis of LN status. LODDS was a better predicator of survival when LN status was modeled as a continuous variable, especially among those patients with either very low or high LNR.
