A Multi-institutional Analysis of Open Versus Minimally-Invasive Surgery for Gastric Adenocarcinoma: Results of the US Gastric Cancer Collaborative

Surgical experience with minimally invasive surgery (MIS) has increased; however, published reports on MIS resection of gastric adenocarcinoma are limited. Between 2000 and 2012, 880 patients who underwent surgical resection of gastric adenocarcinoma were identified from a multi-institutional database. Clinicopathological characteristics, operative details, and outcomes were stratified by operative approach (open vs. MIS) and analyzed. Overall, 70 (8 %) patients had a MIS approach. Patients who underwent a MIS resection were more likely to have a smaller tumor (open 4.5 cm vs. MIS 3.0 cm, p < 0.001). MIS resections were associated with lower estimated blood loss (open 250 cc vs. MIS 150 cc) and longer operative time (open 232 min vs. MIS 271 min) compared with open surgery (both p < 0.05). An R0 resection was achieved in most patients (open 90.9 % vs. MIS 98.6 %, p = 0.03) and median lymph node yield was good in both groups (open 17 vs. MIS 14, p = 0.10). MIS had a similar incidence of complications (open 33.1 % vs. MIS 20 %, p = 0.07) and a similar length of stay (open 9 days vs. MIS 7 days, p = 0.13) compared with open surgery. In the propensity-matched analysis, median recurrence-free and overall were not impacted by operative approach. An MIS approach to gastric cancer was associated with adequate lymph node retrieval, a high incidence of R0 resection, and comparable long-term oncological outcomes versus open gastrectomy

A Nomogram to Predict Overall Survival and Disease-Free Survival After Curative Resection of Gastric Adenocarcinoma

The American Cancer Society projects there will be over 22,000 new cases, resulting in nearly 11,000 deaths, related to gastric adenocarcinoma in the US in 2014. The aim of the current study was to find clinicopathologic variables associated with disease-free survival (DFS) and overall survival (OS) following curative resection of gastric adenocarcinoma, and create a nomogram for individual risk prediction. A nomogram to predict DFS and OS following surgical resection of gastric adenocarcinoma was constructed using a multi-institutional cohort of patients who underwent surgery for primary gastric adenocarcinoma at seven major institutions in the US between January 2000 and August 2013. Discrimination and calibration of the nomogram were tested by C-statistic, Kaplan-Meier curves, and calibration plots. A total of 719 patients who underwent surgery for primary gastric adenocarcinoma were included in the study. Using the backward selection of clinically relevant variables with Akaike information criteria, age, sex, tumor site, depth of invasion, and lymph node ratio (LNR) were selected as factors predictive of OS, while age, tumor site, depth of invasion, and LNR were incorporated in the prediction of DFS. A nomogram was constructed to predict OS and DFS using these variables. Discrimination and calibration of the nomogram revealed good predictive abilities (C-index, DFS 0.711; OS 0.702). Independent predictors of recurrence and death following surgery for primary gastric adenocarcinoma were used to create a nomogram to predict DFS and OS. The nomogram was able to stratify patients into prognostic groups, and performed well on internal validation

Impact of External-beam Radiation Therapy on Outcomes among Patients with Resected Gastric Cancer: A Multi-institutional Analysis

Use of perioperative chemotherapy (CTx) alone versus chemoradiation 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. Using the multi-institutional US Gastric Cancer Collaborative database, we identified 505 gastric cancer patients between 2000 and 2012 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. Median patient age was 62 years, and most patients were male (58.2 %). Most patients had a T3 (38.7 %) or T4 (36.8 %) lesion and lymph node metastasis (73.4 %). A total of 211 (42.8 %) patients received perioperative CTx alone, whereas the remaining 294 (58.2 %) patients received cXRT. Factors associated with receipt of cXRT were younger age (odds ratio, 1.93) and lymph node metastasis (odds ratio, 4.02; both P < 0.05). At a median follow-up of 28 months, the median overall survival (OS) was 33.4 months, and the 5-year OS was 36.7 %. Factors associated with worse overall survival included large tumor size [hazard ratio (HR), 1.83], T3 (HR 2.96) or T4 (HR 4.02) tumors, and lymph node metastasis (HR 1.57; all P < 0.05). In contrast, receipt of cXRT was associated with improved long-term OS (CTx alone, 20.9 months; cXRT, 46.7 months; HR 0.51; P < 0.001). cXRT was utilized in 58 % of patients undergoing curative-intent resection for gastric cancer. With propensity score-matched analysis, cXRT was an independent factor associated with improved recurrence-free survival and OS

Prognostic Performance of Different Lymph Node Staging Systems After Curative Intent Resection for Gastric Adenocarcinoma

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

Conditional Survival after Surgical Resection of Gastric Cancer: A Multi-Institutional Analysis of the US Gastric Cancer Collaborative

Survival estimates following surgical resection of gastric adenocarcinoma are traditionally reported as survival from the date of surgery. Conditional survival (CS) estimates, however, may be more clinically relevant by accounting for time already survived. We assessed CS following surgical resection for gastric adenocarcinoma. We analyzed 807 patients who underwent resection for gastric adenocarcinoma from 2000 to 2012 at seven participating institutions in the U.S. Gastric Cancer Collaborative. Cox proportional hazards models were used to evaluate factors associated with overall survival. Three-year CS estimates at "x" year after surgery were calculated as follows: CS3 = S(x+3)/S-(x). Overall 1-, 3-, and 5-year overall survival rates after gastric resection were 42, 34, and 30 %, respectively. Using CS estimates, the probability of surviving an additional 3 years given that the patient had survived at 1, 3, and 5 years were 56, 71, and 82 %, respectively. Patients with higher risk at baseline (i.e., stage III or IV disease, lymphovascular invasion) demonstrated the greatest increase in CS over time. Survival estimates following surgical resection of gastric adenocarcinoma is dynamic; the probability of survival increases with time already survived. Patients with worse prognostic features at the time of surgery had the greatest increases in CS over time. Conditional survival estimates provide important information about the changing probability of survival over time and should be used among patients with resected gastric adenocarcinoma to guide subsequent follow-up strategies

Impact of External-Beam Radiation Therapy on Outcomes Among Patients with Resected Gastric Cancer: A Multi-institutional Analysis

Use of perioperative chemotherapy (CTx) alone versus chemoradiation 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. Using the multi-institutional US Gastric Cancer Collaborative database, we identified 505 gastric cancer patients between 2000 and 2012 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. Median patient age was 62 years, and most patients were male (58.2 %). Most patients had a T3 (38.7 %) or T4 (36.8 %) lesion and lymph node metastasis (73.4 %). A total of 211 (42.8 %) patients received perioperative CTx alone, whereas the remaining 294 (58.2 %) patients received cXRT. Factors associated with receipt of cXRT were younger age (odds ratio, 1.93) and lymph node metastasis (odds ratio, 4.02; both P < 0.05). At a median follow-up of 28 months, the median overall survival (OS) was 33.4 months, and the 5-year OS was 36.7 %. Factors associated with worse overall survival included large tumor size [hazard ratio (HR), 1.83], T3 (HR 2.96) or T4 (HR 4.02) tumors, and lymph node metastasis (HR 1.57; all P < 0.05). In contrast, receipt of cXRT was associated with improved long-term OS (CTx alone, 20.9 months; cXRT, 46.7 months; HR 0.51; P < 0.001). cXRT was utilized in 58 % of patients undergoing curative-intent resection for gastric cancer. With propensity score-matched analysis, cXRT was an independent factor associated with improved recurrence-free survival and OS