Background Current staging and treatment guidelines for gastric adenocarcinoma do not differentiate between linitis plastic (LP) and non-LP cancers. Significant controversy exists regarding the surgical management of LP patients. Methods Using the multi-institutional U.S. Gastric Cancer Collaborative database, 869 gastric cancer patients who underwent resection between 2000 and 2012 were identified. Clinicopathologic and outcomes data of 58 LP patients were compared to 811 non-LP patients. Results Stage III/IV disease was more common at presentation in LP patients compared with non-LP patients (90 vs. 44 %, p < 0.01). Despite the fact that most LP patients underwent total gastrectomy (88 vs. 39 %, p < 0.01), final positive margins were more common in LP patients (33 vs. 7 %, p < 0.01). The use of frozen section allowed 15 intraoperative positive margins in 38 patients to be converted to negative final margins. Median overall survival (OS) was significantly worse in patients with LP (11.6 vs. 37.8 months, p < 0.01). There was no difference in median OS of LP patients based on stage (I/II, 17.3 mo; III, 10.6 mo; IV, 12.0 mo; p = 0.46). LP and non-LP patients who underwent optimal resection (negative margin and D2/3 lymphadenectomy) had better survival compared with those with nonoptimal resections. The median OS for optimally resected stage III LP (n = 22) and stage III non-LP (n = 185) patients was nearly identical (26.7 vs. 25.3 mo; p = 0.69). Conclusions Future staging systems and treatment guidelines should differentiate between LP and non-LP gastric cancers. Long-term survival in select LP patients who undergo optimal resections is comparable to optimally resected non-LP patients.

84 Background: Use of perioperative chemotherapy (CTx) alone versus chemo-radiation therapy (cXRT) in the treatment of resectable gastric cancer remains varied. We sought to define the utilization and effect of CTx alone versus cXRT on patients having undergone curative-intent resection for gastric cancer. Methods: Using the multi-institutional U.S. Gastric Cancer Collaborative database, we identified 505 patients between 2000 and 2012 with gastric cancer who received perioperative therapy in addition to curative-intent resection. The impact of perioperative therapy on survival was analyzed by the use of propensity-score matching of clinicopathologic factors among patients who received CTx alone versus cXRT. Results: Median patient age was 62 years and the majority of patients were male (58%). Surgical resection involved either partial gastrectomy (54%) or total gastrectomy (46%). On pathology, median tumor size was 5.0 cm; most patients had a T3 (37%) or T4 (36%) lesion and lymph node metastasis (74%). Margin status was R0 in most patients (89%). 211 (42%) patients received perioperative CTx alone whereas the remaining 294 (58%) patients received 5-FU based cXRT. Factors associated with receipt of cXRT were younger age (OR 0.98), T3 tumors (OR 1.52), and lymph node metastasis (OR 2.03) (all P < .05). Recurrence occurred in 214 (39%) patients. At a median follow-up of 28 months, median overall survival (OS) was 33.4 months and 5-year survival was 36.7%. Factors associated with worse OS included tumor size (HR 1.1), T-stage (HR 1.5), and lymph node metastasis (HR 1.58) (all P<0.05). In contrast, receipt of cXRT was associated with improved long-term OS (CTx alone: 21 months vs. cXRT 45 months; p<0.001). In the propensity-matched multivariate model that adjusted for tumor size, T-stage, and nodal status, cXRT remained associated with an improved long-term disease-free (HR 0.43) and overall (HR 0.41) survival (both P<0.001). Conclusions: XRT was utilized in 58% of patients undergoing curative-intent resection for gastric cancer. Using propensity-matched analysis, cXRT was an independent factor associated with improved recurrence-free and overall survival.

137 Background: Limited data exist on the prognostic implication of pre-operative Helicobacter pylori (H. pylori) infection in gastric adenocarcinoma (GAC). Our aim was to assess the association of H. pyloriwith recurrence and survival in patients undergoing resection of GAC. Methods: All patients who underwent curative intent resection for GAC from 2000 to 2012 at seven academic institutions comprising the US Gastric Cancer Collaborative were included. 30-day mortalities were excluded. Survival analyses were conducted with Kaplan Meier log rank and multivariate Cox regression. Primary endpoints were recurrence-free survival (RFS) and overall survival (OS). Results: Of 965 patients, 559 met inclusion criteria and had documented pre-operative H. pylori testing. 18.6% (n=104) of patients tested positive for H. pylori pre-operatively. Data regarding treatment of H. pylori was not available. H. pylori infection was associated with younger age (62.1 vs 65.1 years; p=0.041), distal tumor location (82.7% vs 71.9%; p=0.033), and receipt of adjuvant radiation therapy (47.0% vs 34.9%; p=0.032). There were no significant differences in ASA class, margin status, Grade, PNI, LVI, or nodal metastases. The distribution of TNM stage I-III was similar between the two groups. H. pylori status was not associated with tumor recurrence. However, pre-operative H. pylori infection was associated with longer OS (84.3 mo vs 44.2 mo; p=0.008). When accounting for differences in age, tumor location, and delivery of radiation therapy, H. pylori infection persisted as a positive prognostic factor for OS (HR 0.60; CI 0.40-0.91; p = 0.016). Conclusions: Patients with and without preoperative H. pylori infection had no significant differences in adverse pathologic factors including positive margin, high grade, lymph node metastases, or advanced TNM stage. Despite similar disease presentation, pre-operative H. pylori infection was independently associated with improved overall survival. Further studies examining the interaction between H. pylori and tumor immunology and genetics are needed to better understand the relationship between H. pylori and survival in gastric cancer.

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5 Background: The negative impact of postoperative complications (POCs) on survival is well documented for many cancer types, but has not been well described in gastric cancer. Here, we evaluated the effect of POCs on survival after surgery for gastric cancer in a cohort of patients from a multi-institutional database. Methods: Patients who underwent surgery with curative intent for gastric adenocarcinoma between 2000-2012 from participating institutions of the U.S. Gastric Cancer Collaborative were analyzed. Patients who died within 30 days of surgery were excluded. Ninety-day postoperative complication data were collected. Survival probabilities were estimated by Kaplan-Meier analysis and compared using the log-rank test. Results: A total of 853 patients from seven institutions met inclusion criteria. Median follow-up was 32 months. The overall complication rate was 40% (n=344). The most frequent complications were: infectious (25%, including surgical site infection [8%]), and anastomotic leak (6%). 7% of patients underwent reoperation during the same hospitalization. Five-year overall survival (OS) for patients without perioperative complications was 54%, compared with 39% for patients with POCs (p=0.001). Disease free survival (DFS) at five years was 61% for patients without POCs compared to 49% in patients with POCs (p=0.002). Patients without POCs were significantly more likely to receive adjuvant therapy (55% vs 42%; p<0.001). Conclusions: In a large, multi-institutional cohort, POCs were associated with decreased survival in patients undergoing surgery for gastric adenocarcinoma. This may be due, in part, to the negative impact of complications on the receipt of adjuvant therapy. Efforts aimed at reducing perioperative morbidity are important not only for short-term surgical outcomes, but also for enhancing long-term oncologic outcomes in patients with gastric cancer. [Table: see text]