Maruyama index (MI) and outcomes of gastric cancer resection.

Abstract

4154 Background: Benefit of extensive lymph node (LN) dissections (D2 vs. D1) for gastric cancer is debated. The cumulative probability of tumor in all LN stations (total MI: TMI) and stations not removed (MI of unresected disease: MIUD) can be calculated. Low MIUD but not D2 dissection correlated with better survival in INT-0116 and the Dutch D2 trial. We evaluated the predictive ability of MI for key outcomes of gastric cancer resection. Methods: Institutional review of all curative-intent gastric cancer resections from 1999 to 2008. TMI and MIUD were calculated using age, gender, Borrmann type, depth of invasion, tumor location, position, grade, and histology. Correlation with tumor stage, R0 resection, and survival was analyzed. Log rank test for survival comparisons, Wilcoxon Mann Whitney and Kruskal Wallis tests for comparison between medians and proportional hazard models were employed. Results: Table: patient and tumor characteristics, N = 108. Median TMI and MIUD were 160 and 60 respectively, lower for the R0 than R1/2 resections (median TMI R0: 140 vs. R1/2: 360, p < 0.0001; median MIUD R0: 36 vs. R1/2: 131, p < 0.0001). TMI correlated with stage (median TMI stage I 100; stage II 133; stage III 297; stage IV 360: p < 0.0001). Lower MIUD as a continuous (p< 0.02) and categorical (p< 0.04) variable correlated with better survival (5 year survival MIUD < 60: 68% vs. MIUD ≥ 60: 36%). MIUD, R status, and stage independently predicted survival on univariate analysis, but not on multiple variable modeling. Conclusions: In our community-based gastric cancer resection cohort, MI correlated with more extensive disease at surgery and incomplete resections. We confirmed the predictive ability of MIUD for survival. MI may be a valuable preoperative surrogate for tumor stage and may identify patients needful of intensive preoperative staging and treatment to avoid futile resections. Tailored removal of LN as predicted by the MI may improve survival. % Age (yrs) Median 66 (25-93) Gender Female 43 Male 57 Race Black 63 White 30 Other 7 Tumor location Distal 64 Middle 22 Proximal 13 Position Lesser curvature 45 Greater curvature 20 Posterior 16 Anterior 8 Circumferential 12 Borrmann type I 6 II 13 III 65 IV 16 Grade Well 6 Moderate 31 Poor 61 Stage I 24 II 22 III 31 IV 22 R status R0 72 R1 22 R2 5 Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Genentech