24 Background: Previous investigators have reported on the value of lymph node ratio (LNR, defined as the number of positive nodes divided by the total number of nodes assessed) in gastric adenocarcinoma (GAC) staging. Given the complexity of previously proposed staging systems, it has not gained widespread acceptance. The aim of our study was to offer a novel simplified approach to incorporating LNR into gastric cancer staging. Methods: 131 patients who underwent curative intent resection with lymphadenectomy for GAC between 1/00-6/11 were identified. Clinicopathologic factors were assessed. Primary outcome was overall survival (OS). Results: Median age was 64 yrs, 51% were male. Median tumor size was 3.5 cm, 67% were poorly differentiated, 20% had perineural invasion, 31% had lymphovascular invasion, and 6% had a positive margin. Locoregional nodal metastases were present in 59% (n=77, N0: 41%, N1: 18%, N2: 22%, N3a: 14%, N3b: 5%). Median number of lymph nodes (LN) assessed was 15.5. Mean FU was 27.3 mos, median OS was 29.3 mos. Median LNR was 0.4 (.04-1). Patients with LNR ≥0.4 had decreased OS as compared to patients with LNR <0.4 (15.1 vs 41.5 mos, p<0.0001); the survival of patients with LNR <0.4 was similar to that of node negative pts (48 mos, p=0.882). On Cox regression analysis, LNR ≥0.4 was more strongly associated with decreased OS (HR 3.09, 95%CI: 1.81-5.26; p<0.0001) compared to the AJCC 7th edition N stage (HR 1.36, 95%CI: 1.11-1.68; p=0.004). In the subset of patients who were inadequately staged and had <16 nodes examined, a LNR ≥0.4 was associated with reduced survival compared to a LNR <0.4 (17.3 vs 41.5 mos, p=.04). Conclusions: Compared to the current lymph node staging system, a lymph node ratio using 0.4 as the cutoff may more accurately predict survival outcomes. It seems to be particularly useful in patients who have inadequate nodal assessment. This simplified approach to lymph node ratio may be a more valuable staging tool than the current AJCC nodal staging system for gastric cancer and needs to be validated.
Positive lymph node ratio is an index in predicting prognosis for remnant gastric cancer with insufficient retrieved lymph node in R0 resection
