Impact of the 7th Edition AJCC staging classification on the NCCN clinical practice guidelines in oncology for gastric and esophageal cancers

The 7th edition of the AJCC Cancer Staging Manual has attempted to harmonize gastric and esophageal cancers, including management of gastroesophageal junction (GEJ)-type tumors. The treatment of complex tumor types is best guided by a staging classification that reliably groups patients according to prognosis and therapy. This article reviews and discusses these changes with the goal of elucidating key features of the staging system and outlining how these changes relate to the NCCN Clinical Practice Guidelines in Oncology with regard to the care and treatment of patients. The 7th edition of the AJCC Cancer Staging Manual has certainly improved harmonization of gastric and distal esophageal/GEJ-type adenocarcinomas, although issues persist, particularly regarding the optimal neoadjuvant treatment for the management of GEJ carcinomas.

Preoperative chemotherapy plus bevacizumab with early salvage therapy based on FDG-PET response in locally advanced gastroesophageal junction and gastric adenocarcinoma

4101

Background: Response on FDG-PET scan during preoperative chemotherapy has prognostic significance. We performed a phase II trial to examine the effectiveness of FDG-PET directed early switching to salvage chemotherapy measured by 2-year disease free survival (DFS). Methods: Pts with PET avid, endoscopic ultrasound and laparoscopically staged T3 or N+ resectable gastric or GEJ adenocarcinoma received induction epirubicin 50mg/m2, cisplatin 60mg/m2 Day 1, capecitabine 625mg/m2 BID Days 1-21 (ECX) and bevacizumab 15mg/kg Day 1. PET scan was repeated at Week 3. PET responders (≥35% decline in SUV) continued with ECX for 2 more cycles. PET non-responders were switched to 2 cycles of salvage therapy: docetaxel 30mg/m2 and irinotecan 50mg/m2Days 1 and 8 q21 days and bevacizumab 15mg/kg Day 1. All pts went to surgery 4 weeks after Cycle 3. Results: Twenty of planned 60 pts were enrolled before the study closed for poor accrual. Eleven (55%) had a PET response after induction. Ten of 11 underwent R0 resection: 1/10 path complete response, 3/10 path partial response. Nine PET non-responders were switched to the salvage regimen. Seven of 9 non-responders had R0 resection, none achieved a pathological response. The median DFS for PET responders was 27.8 mos (95% CI 10.3-27.8) and DFS in salvage group has not been reached. There was no significant difference in DFS between the two groups (p= 0.4). Follow up for overall survival is ongoing. Conclusions: Response on PET scan during induction chemotherapy can identify early treatment failures. The results for therapy cross-over indicate a potentially improved DFS with salvage chemotherapy. Results from this trial are hypothesis generating and merit evaluation in a larger clinical trial. Updated survival data will be presented. Clinical trial information: NCT00737438.

Variable penetrance of CDH1 mutation diffuse gastric cancer: A genomic analysis

4082

Background: CDH1 encodes E-cadherin; mutations (CDH1mut) increase the risk of diffuse gastric (DGC) and lobular breast cancers. Life-time risk of DGC is estimated at 80%. Current recommendations are prophylactic gastrectomy (PG) in CDH1mut carriers after age 20. Foci of DGC are found in some PG; others have none at PG, and some CDH1mut without PG never develop cancer. Identifying risk modifying alleles or other genomic events which increase the risk of DGC may improve understanding of DGC and may provide a biomarker for when to perform PG. Methods: For a Gastric Cancer Registry, we collected family pedigrees, germline DNA and FFPE tumor from CDH1mut DGC patients (pts) and their families. From 24 families, with 52 CDH1mut individuals, we identified 4 families in which a young CDH1mut pt developed advanced DGC while their CDH1mut parent and siblings had no clinical evidence of DGC. Several relatives had undergone PG with no DGC found. We hypothesize that there are risk modifying alleles and/or a “second hit” that causes variable penetrance and early onset of DGC in the young CDH1mut pts. Whole genome sequencing was performed on germ line DNA (Complete Genomics, Inc. Mountain View, CA); and whole exome sequencing on tumor specimens (MSKCC). Results: To date, 4 DGC pts and 8 relatives from 4 families have been studied. All 4 affected pts were women (ages 17, 25, 27, 42); their unaffected CDH1mut parents were 41, 51, 54, and 70 years old. The families are of Kenyan, Scandinavian, Italian, Eastern European, and Scottish origin. CDH1 mutations for the pts and their families were confirmed on WGS, and were as follows: 1451C>A(pro484his);c. 1792C>T (arg598ter);c. 1893dupA in exon 12;c. 1565+1G>A (IVS10+1G>A). Analysis of germline DNA for modifying alleles is being performed (Ingenuity Systems, Redwood, Ca.); whole exome sequencing of tumor to identify a possible "second hit" is underway. These data will be presented. Conclusions: Since at least some older pts with proven CDH-1mut do not develop DGC while their children do, CGH-1mut alone may not be sufficient to cause early onset DGC. We hope to identify the additional genomic events associated with early onset advanced DGC. Supported in part by grants from the Gerstner and DeGregorio Foundations.

Esophagojejunal reconstruction after total gastrectomy for gastric cancer using a transorally inserted anvil delivery system

INTRODUCTION

Total gastrectomy (TG) is commonly performed for the treatment of patients with gastric cancer. However, reconstruction of the esophagojejunal (EJ) anastomosis can be technically demanding, with reported anastomotic leak rates in the Western world still approaching 10-15%. We report our experience using the transoral anvil delivery system (OrVil™) for creation of the EJ anastomosis after TG.

METHODS

From 2007 to 2011, 48 consecutive patients with gastric cancer underwent open (n=31) or laparoscopic (n=17) TG. EJ reconstruction was performed with the transoral anvil deliver system (OrVil™) in an end-to-side fashion. Demographic, clinic, and perioperative data were obtained from a prospectively maintained database.

RESULTS

Of the 48 patients, 83% were male. Median age at resection was 64 years. Median body mass index was 27.1 kg/m2. Seventy-nine percent (n=38) of patients had at least one comorbidity. Fifteen patients (31%) had at least one perioperative complication. There was one perioperative death (2%) following a duodenal stump leak. There were four EJ leaks (8%) and two EJ stenoses (independent of leak; 4%). There was one EJ leak (6%) and one EJ stenosis (6%) following a case that was first attempted laparoscopically. There were no deaths as a consequence of an EJ leak.

CONCLUSIONS

The use of the transoral anvil delivery system during EJ reconstruction is a safe and effective option for reconstruction after open or laparoscopic TG with acceptable mortality and morbidity. The anastomotic leak rate appears to be comparable to that of other techniques.

Phase II study of preoperative chemotherapy plus bevacizumab with early salvage therapy based on FDG-PET response in patients with locally advanced gastric and GEJ adenocarcinoma

94

Background: Response on FDG-PET scan during preoperative chemotherapy has prognostic significance. PET non-responders do poorly whether they continue the same chemotherapy or proceed directly to surgery [JCO 24: 4692; 2006, Lancet Onc 8:797;2007) Early identification of treatment failure using PET scan may spare patients (pts) from inactive therapy and allow for cross-over to alternative therapies. We performed a phase II trial to examine the effectiveness of FDG-PET directed early switching to salvage chemotherapy measured by 2 year disease free survival (DFS) in the PET non-responding group. Methods: Pts with PET avid, EUS and laparoscopically staged T3 or Node positive resectable gastric or GEJ adenocarcinoma received induction with epirubicin 50mg/m2, cisplatin 60mg/m2, capecitabine 625mg/m2 bid days 2-21(ECX) and bevacizumab 15mg/kg day 1. PET scan was repeated at week 3. PET responders (≥35% decline in SUV) continued ECX for 2 more cycles. PET non-responders switched to 2 cycles of salvage therapy: docetaxel 30mg/m2 d1, d8 q21 days, irinotecan 50mg/m2 d1, d8 q21 days and bevacizumab 15mg/kg day 1. Pts had surgery 4 weeks after cycle 3. Results: 20 of planned 60 pts were enrolled before the study closed for poor accrual. 14 male (64%), 8 female (39%), median age 62, median KPS 90. 11(55%) had a PET response after the first cycle. 10/11 (91%) underwent R0 resection: 1/10 pathologic CR, 3/10 pathologic PR. 9/20 PET non-responders switched to the salvage regimen. 7/9 Non-responders had R0 resection, none achieved a pathological response. The DFS for PET responders was 27.8mos (95% CI 10.3-27.8) and DFS in salvage group has not been reached. There was no significant difference in DFS between the two groups (p= 0.4). Follow up for overall survival is ongoing. Biologic correlative studies are pending. Conclusions: Response on PET scan during induction chemotherapy can identify early treatment failures. The results for therapy cross-over indicate a potentially improved DFS with salvage chemotherapy. Results from this trial are hypothesis generating and merit evaluation in a larger clinical trial. Supported by a grant from Genentech. Clinical trial information: NCT00737438.

Comparison of disease-specific survival in the United States and Korea after resection for early-stage node-negative gastric carcinoma

BACKGROUND AND OBJECTIVES

Disease-specific survival (DSS) for GC patients differs in Eastern and Western countries. The aim is to compare outcomes of US and Korean patients following resection of early-stage, node-negative gastric carcinoma (GC).

METHODS

All patients (1995-2005) with T1N0 gastric carcinoma, excluding gastroesophageal tumors, were evaluated. DSS was compared by adjusting for prognostic variables from an internationally validated GC nomogram.

RESULTS

The cohort included 598 Korean patients and 159 US patients. Age and BMI were significantly higher in US patients. Distal tumor location was more frequent in Korea (60% vs. 52%) and proximal location in the US (19% vs. 5%, P < 0.0001). Five-year DSS did not differ significantly between Korea and the US. After multivariate analysis, DSS of Korean patients persisted, with no significant differences when compared to US patients (HR = 1.2, 95% CI: 0.3-5.2, P = 0.83).

CONCLUSIONS

Despite widespread speculations that GC differs in the East and West, when we compare similarly staged, node-negative GC patients, survival did not differ significantly between Korea and the US. This suggests that GC is a heterogeneous disease and when similar subtypes of gastric cancer are compared, these differences disappear. This study suggests more similarities than previously hypothesized between US and Korean GC patients.

Establishment of esophagogastric xenografts: A model for characterizing disease heterogeneity

95

Background: Gastric cancer is a heterogeneous disease that may be subdivided into distinct subtypes—proximal/gastroesophageal (GE) junction, diffuse/signet ring type, and distal gastric cancer/intestinal type—based on histopathologic and anatomic criteria. Each subtype is associated with unique epidemiology and gene expression. Human epidermal growth factor receptor (HER2) is a validated treatment target in gastric cancer. For patients with metastatic disease, the available cytotoxic agents are applied indiscriminately to all disease subtypes, and with only modest success. The purpose of this study is to establish xenograft models from gastric cancer subtypes to improve our understanding of disease heterogeneity and develop therapies geared for each subtype of gastric cancer. Methods: Fresh specimens obtained from resected primary or metastatic tumors under aseptic conditions. 1 g tumor samples injected SQ into flanks of NSG mice. Xenografts established after 5 passages and maintained by serial transplantation into new mice. Cell cultures established after 5 in vitro passages; cell lines after 15 passages Results: To date, 66 tumor samples have been implanted from which 16 xenografts have been established. The table below summarizes the results. Single-agent afatinib (pan-ErbB inhibitor) demonstrated antitumor activity in an HER2-positive xenograft established from MSKCC patient’s tumor harvested from a skin metastasis. Conclusions: We have established xenograft models of gastric cancer. In vivo testing of afatinib showed a reduction of tumor growth of HER2-positive gastric cancer. These models provide a platform to study potential therapeutics for esophagogastric cancer to further validate difference in their biology and guide rational design of clinical trials. [Table: see text]

Blood neutrophil-to-lymphocyte ratio is prognostic in gastrointestinal stromal tumor

BACKGROUND

The immune system has been shown to play an important role in gastrointestinal stromal tumor (GIST). The neutrophil-to-lymphocyte ratio (NLR) in blood is an easily assessable parameter of systemic inflammatory response. The aim of this study was to determine whether the NLR is prognostic in GIST.

METHODS

A total of 339 previously untreated patients with primary, localized GIST operated at our institution between 1995 and 2010 were identified from a prospectively collected sarcoma database. NLR was assessed preoperatively. Patients who received adjuvant imatinib treatment were excluded from the analysis (n = 64). Cox regression models were calculated and correlation analyses were performed.

RESULTS

On univariate analysis, NLR was associated with recurrence-free survival (RFS) (P = 0.003, hazard ratio 3.3, 95 % confidence interval 1.5-7.4). Patients with a low NLR had a 1- and 5-year RFS of 98 and 91 %, compared with 89 and 76 % in those with a high NLR. The median RFS was not reached. Positive correlations were found between NLR and mitotic rate (Pearson correlation coefficient [r] = 0.15, P = 0.03), and NLR and tumor size (r = 0.36, P = 0.0001). RFS in patients with a GIST >5 cm with low NLR was significantly longer compared to patients with high NLR (P = 0.002). Flow cytometry analysis of freshly obtained GISTs revealed that neutrophils constituted a minimal percentage of intratumoral immune cells.

CONCLUSIONS

NLR is a surrogate for high-risk tumor features. Elevated blood NLR appears to represent systemic inflammation in patients with high-risk GIST.

Impact of obesity on perioperative complications and long-term survival of patients with gastric cancer

BACKGROUND

The prevalence of obesity is increasing in the United States. Obesity has been associated with worse surgical outcomes, but its impact on long-term outcomes in gastric cancer is unclear. The aim of this study was to evaluate the effects of being overweight on surgical and long-term outcomes for patients with gastric cancer.

METHODS

Patients who underwent curative intent resection for gastric carcinoma from 1985 to 2007 were identified from a prospectively collected gastric cancer database. Overweight was defined as a body mass index (BMI) of 25 kg/m(2) or higher. Clinical outcomes of overweight and nonoverweight patients were compared.

RESULTS

From the total population of 1,853 patients, 1,125 (60.7%) were overweight. Overweight patients tended to have more proximal tumors and a lower T stage. Accurate complication data were available on a subset of patients from 2000 to 2007. A BMI of ≥25 was associated with increased postoperative complications (47.9 vs. 35.8%, p < 0.001). This was mainly due to an increase in the rate of wound infections (8.9 vs. 4.7%, p = 0.02) and anastomotic leaks (11.8 vs. 5.4%, p = 0.002). Multivariate logistic regression analysis showed that higher BMI, total gastrectomy, and use of neoadjuvant chemotherapy were associated with increased wound infection and anastomotic leak. Overweight patients were less likely to have adequate lymph node staging (73.3 vs. 79.2%, p = 0.047). There was no difference in overall survival or disease-specific survival between the two groups.

CONCLUSIONS

Increased BMI is a predictor of increased postoperative complications, including anastomotic leak, but it is not a predictor of survival in gastric cancer.

Role of repeat staging laparoscopy in locoregionally advanced gastric or gastroesophageal cancer after neoadjuvant therapy

INTRODUCTION

Staging laparoscopy (SL) can identify occult, subradiographic metastatic (M1) disease in patients with gastric or gastroesophageal (G/GEJ) cancer who are unlikely to benefit from gastrectomy. The purpose of this study is to determine the yield of repeat SL following neoadjuvant therapy for G/GEJ adenocarcinoma after initial negative pretreatment SL.

METHODS

Retrospective review of a prospective database identified patients with locoregionally advanced (T3-4Nany or TanyN+) G/GEJ adenocarcinoma who underwent pretreatment SL. The yield of repeat SL following neoadjuvant therapy was determined.

RESULTS

From 1994 to 2010, 276 patients with locoregionally advanced G/GEJ adenocarcinoma were identified, of whom 244 proceeded to operation after neoadjuvant therapy, at a median time of 105 days. One hundred sixty-four patients (67 %) underwent repeat SL, and 80 patients (33 %) proceeded directly to laparotomy. Occult M1 disease was identified in 12 (7.3 %) and 6 (7.5 %) patients, respectively. In the repeat SL cohort, M1 disease was identified at laparoscopy in nine patients (5.5 %). M1 disease not identified by laparoscopy was discovered at laparotomy in three patients (1.8 %). The median follow-up for the study population was 31 months. For patients with M1 disease, median overall survival was 15 months, versus 41 months for patients resected without M1 disease (p < 0.0001).

CONCLUSIONS

Occult, subradiographic M1 disease develops in approximately 7 % of patients following neoadjuvant therapy for locoregionally advanced G/GEJ adenocarcinoma. These patients have poor prognosis, and repeat SL can be a valuable tool in selecting patients with locoregionally advanced G/GEJ tumors for potentially curative resection after neoadjuvant therapy.

Laparoscopic transabdominal lateral adrenalectomy

Laparoscopic adrenalectomy is a mainstay of operative options for adrenal tumors and allows surgeons to perform adrenalectomies with less morbidity, less post-operative pain, and shorter hospital stays. The literature has demonstrated its efficacy to be equal to open adrenalectomy in most cases. With regard to malignant primary and metastatic lesions, controversy still remains, however, consideration of a laparoscopic approach for smaller, well circumscribed and non-invasive lesions is reasonable. During any laparoscopic resection, when there is doubt about the ability to safely remove the lesion with an intact capsule, conversion to an open approach should be considered. The primary goal of a safe and complete oncologic resection cannot be compromised. For most benign lesions, laparoscopic approaches are safe and feasible and conversion to an open approach is necessary only for lesions where size limits the ability of a minimally invasive resection.

Minimally invasive surgery for gastric cancer

Application of minimally invasive techniques to gastric cancer in the West has been curbed by concerns of feasibility and oncologic adequacy. Growing evidence supports improved short-term and equivalent oncologic outcomes in selected patients undergoing laparoscopic surgery for early-stage disease. Laparoscopic resection for advanced gastric cancer remains controversial due to few reliable studies on long-term outcomes. We focus on important studies from Asia and highlight the Western experience with laparoscopic and robotic surgery for gastric carcinoma.

Comparisons of Gastric Cancer Treatments: East vs. West

There has been a large amount of speculation concerning the differences in the outcomes in patients who have gastric cancer in the Eastern and Western worlds. The differences in biology, surgical and adjuvant treatment have been used to explain such differences. There are clear differences observed in the histology (diffuse vs. intestinal), tumor location (proximal vs. distal), environmental exposures, dietary factors and Helicobacter pylori status. A higher incidence of gastric cancer in the East has led to screening programs, and leading to an earlier stage at presentation. Surgical treatment differs in that the extended lymph node dissection is routinely practiced in the Asian countries. Additionally, different adjuvant therapeutic regimens are used in both regions. The purpose of this review is to describe the differences in both presentation and treatment between the East and the West.

A prospective evaluation of the utility of 2-deoxy-2-[(18) F]fluoro-D-glucose positron emission tomography and computed tomography in staging locally advanced gastric cancer

BACKGROUND

The aim of this study was to examine prospectively the utility of adding preoperative [(18) F]fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT) to routine CT, endoscopic ultrasound (EUS), and laparoscopic staging of localized gastric cancer.

METHODS

Patients with locally advanced gastric/gastroesophageal cancer were screened for 2 institutional review board-approved Memorial Sloan-Kettering Cancer Center neoadjuvant chemotherapy protocols. Locally advanced disease was defined as T3 or T4, or lymph node-positive, based on EUS and high-resolution CT scan. All patients underwent both standard FDG-PET/CT and laparoscopy with cytological examination of washings. The sensitivity and specificity of FDG-PET/CT for the identification of metastatic disease not seen on CT was determined. An economic model using Medicare/Medicaid reimbursement charges was developed to assess the cost-effectiveness of these interventions.

RESULTS

A total of 113 patients were enrolled from 2003 to 2010. All patients were assessed as having locally advanced disease by CT/EUS. FDG uptake in the primary tumor was associated with male sex, proximal tumors, and nondiffuse Lauren's subtype. 31 (27%) patients had occult metastatic disease detected by PET/CT (n = 11, 10%) and/or laparoscopy (n = 21, 19%), with a single overlap. Economic modeling suggests that the addition of FDG-PET/CT to the standard staging evaluation of patients with locally advanced gastric cancer resulted in an estimated cost savings of ∼US $13,000 per patient.

CONCLUSIONS

FDG-PET/CT identifies occult metastatic lesions in approximately 10% of patients with locally advanced gastric cancer. Because of reduced morbidity from fewer futile surgeries and lower patient care costs, PET/CT should be considered as a component of the standard staging algorithm for localized gastric cancer.

Tobacco use is associated with increased recurrence and death from gastric cancer

BACKGROUND

Tobacco use increases the risk of developing gastric cancer. We examined the hypothesis that gastric cancer developing in patients with a history of tobacco use may be associated with increased risk of cancer-specific death after curative surgical resection.

METHODS

From the Memorial Sloan-Kettering Cancer Center Gastric Cancer prospective surgical database, we collected baseline demographic data and tumor characteristics from all patients who had undergone curative resection for gastric cancer between 1995 and 2009 and who had not received pre- or postoperative chemo- or radiotherapy. A smoking history was defined as >100 cigarettes' lifetime use. The primary end point was gastric cancer disease-specific survival (DSS); secondary end points were 5-year disease-free survival (DFS) and overall survival (OS). Gastric cancer-specific hazard was modeled by Cox regression.

RESULTS

A total of 699 eligible patients were identified with a median age of 70 years (range 25-96 years); 410 (59%) were current or previous smokers. Smoking was associated with gastroesophageal junction/cardia tumors and white non-Hispanic ethnicity. Multivariate analysis included the following variables: tumor stage, age, performance status, diabetes mellitus, gender, and tumor location. In this analysis, the hazard ratio for gastric cancer DSS in smokers was 1.43 (95% confidence interval 1.08-1.91, P=0.01). Smoking was also an independent significant risk factor for worse 5-year DFS (hazard ratio 1.46, P=0.007) and OS (hazard ratio 1.48, P=0.003). Among 516 patients for whom tobacco pack-year usage was available, both heavy (≥20 pack-years) and light (<20 pack-years) tobacco use was significantly associated with DSS, DFS, and OS.

CONCLUSIONS

Smoking history appears to be an independent risk factor for death from gastric cancer in patients who have undergone curative surgical resection.

Tobacco use is associated with increased recurrence and death from gastric cancer

BACKGROUND

Tobacco use increases the risk of developing gastric cancer. We examined the hypothesis that gastric cancer developing in patients with a history of tobacco use may be associated with increased risk of cancer-specific death after curative surgical resection.

METHODS

From the Memorial Sloan-Kettering Cancer Center Gastric Cancer prospective surgical database, we collected baseline demographic data and tumor characteristics from all patients who had undergone curative resection for gastric cancer between 1995 and 2009 and who had not received pre- or postoperative chemo- or radiotherapy. A smoking history was defined as >100 cigarettes' lifetime use. The primary end point was gastric cancer disease-specific survival (DSS); secondary end points were 5-year disease-free survival (DFS) and overall survival (OS). Gastric cancer-specific hazard was modeled by Cox regression.

RESULTS

A total of 699 eligible patients were identified with a median age of 70 years (range 25-96 years); 410 (59%) were current or previous smokers. Smoking was associated with gastroesophageal junction/cardia tumors and white non-Hispanic ethnicity. Multivariate analysis included the following variables: tumor stage, age, performance status, diabetes mellitus, gender, and tumor location. In this analysis, the hazard ratio for gastric cancer DSS in smokers was 1.43 (95% confidence interval 1.08-1.91, P=0.01). Smoking was also an independent significant risk factor for worse 5-year DFS (hazard ratio 1.46, P=0.007) and OS (hazard ratio 1.48, P=0.003). Among 516 patients for whom tobacco pack-year usage was available, both heavy (≥20 pack-years) and light (<20 pack-years) tobacco use was significantly associated with DSS, DFS, and OS.

CONCLUSIONS

Smoking history appears to be an independent risk factor for death from gastric cancer in patients who have undergone curative surgical resection.

Laparoscopic versus open distal gastrectomy for gastric cancer: a meta-analysis of randomized controlled trials and high-quality nonrandomized studies

OBJECTIVE

To perform a meta-analysis of high-quality published trials, randomized and observational, comparing laparoscopic distal gastrectomy (LDG) and open distal gastrectomy (ODG) for gastric cancer.

BACKGROUND

Controversy persists about the clinical utility of minimally invasive techniques for the treatment of gastric cancer. Prospective data is limited to a few small randomized trails.

METHODS

: Studies published from January 1992 to March 2010 that compare LDG and ODG were identified. No restrictions in pathologic stage were applied. All randomized controlled trials (RCTs) were included. Selection of high-quality, nonrandomized comparative studies (NRCTs) was based on a validated tool (Methodological Index for Nonrandomized Studies). Mortality, complications, harvested lymph nodes, operative time, blood loss, and hospital stay were compared using weighted mean differences (WMDs) and odds ratios (ORs).

RESULTS

Twenty-five studies were included in the analyses, 6 RCTs and 19 NRCTs, compromising 3055 patients (1658 LDG, 1397 ODG). LDG was associated with longer operative times (WMD 48.3 minutes; P < 0.001) and lower overall complications (OR 0.59; P < 0.001), medical complications (OR 0.49; P = 0.002), minor surgical complications (OR 0.62; P = 0.001), estimated blood loss (WMD -118.9 mL; P < 0.001), and hospital stay (WMD -3.6 days; P < 0.001). Mortality and major complications were similar. Patients in the ODG group had a significantly higher number of lymph nodes harvested (WMD 3.9 nodes; P < 0.001), although the estimated proportion of patients with less than 15 retrieved nodes was similar (OR 1.26, P = 0.09).

CONCLUSIONS

LDG can be performed safely with a shorter hospital stay and fewer complications than open surgery. The long-term significance of a difference of less than 5 nodes in the number of harvested lymph nodes remains unclear. Lymph node staging appears to be unaffected. These results need to be validated in Western patients with advanced gastric cancer.

Laparoscopic resection for gastric carcinoma: Western experience

There has been much speculation regarding differences in outcome for patients who have gastric cancer in the Eastern versus Western world. Among other factors, these differences have contributed to a unique cohort of patients and experience in the Western staging/evaluation of gastric cancer and in the application of minimally invasive approaches for treatment. This review summarizes the current state of laparoscopic approaches for the staging and treatment of gastric adenocarcinoma for patients presenting in Western countries, with their associated unique presentation, comorbidities, and outcomes.

Role of repeat staging laparoscopy in locoregionally advanced gastric cancer after completion of neoadjuvant therapy

11

Background: Staging laparoscopy (SL) can identify occult, subradiographic metastatic disease, either visible or cytologic, defining patients with stage IV gastric cancer who are unlikely to benefit from gastrectomy. The purpose of this study was to characterize the yield of repeat SL performed immediately prior to gastrectomy following administration of neoadjuvant therapy for locoregionally advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinoma.

Methods: Retrospective review of a prospective database identified patients with locoregionally advanced G/GEJ adenocarcinoma (T3−4Nany or TanyN+) that underwent pretreatment SL with negative peritoneal cytology followed by neoadjuvant chemotherapy or chemoradiation. After neoadjuvant therapy, patients underwent repeat SL. The yield of repeat SL to identify metastatic disease (M1) was determined and outcome data were analyzed.

Results: From 1994−2010, 164 patients with locoregionally advanced G/GEJ adenocarcinoma were identified who underwent repeat SL immediately prior to gastrectomy. Occult M1 disease was identified in 12 patients (7.3%). Of these 12 patients, M1 disease was identified at laparoscopy in 9 patients (5.5%)—8 patients had visible disease and 1 patient had peritoneal cytology−only M1 disease. M1 disease not identified by SL was discovered at laparotomy in the other 3 patients (1.8%). There were no complications associated with patients who only underwent SL. Median follow-up was 30 months with a median survival of 18 months for patients with M1 disease and 47 months for patients resected with curative intent without M1 disease (p<0.001).

Conclusions: Repeat staging laparoscopy following neoadjuvant therapy for locoregionally advanced G/GEJ adenocarcinoma identifies 5−6% of patients with clinically occult, subradiographic M1 disease. The majority of M1 disease is identified at repeat SL rather than at laparotomy and the majority is visible as opposed to cytology−only M1. These patients with occult M1 disease have a poor prognosis, are unlikely to benefit from gastrectomy, and repeat SL can avert the morbidity of a non−therapeutic laparotomy in this patient population.

Establishment of primary gastric and gastroesophageal (GE) junction xenografts: A model for characterizing disease heterogeneity

51

Background: Gastric cancer is a heterogeneous disease that may be subdivided into distinct subtypes—proximal/gastroesophageal (GE) junction, diffuse/signet ring type, and distal gastric cancers—based on histopathologic and anatomic criteria. Each subtype is associated with unique epidemiology and gene expression. Human epidermal growth factor receptor (HER2) is a validated treatment target in gastric cancer. For patients with metastatic disease, the available cytotoxic agents are applied indiscriminately to all disease subtypes, and with only modest success. The purpose of this study is to establish xenograft models from gastric cancer subtypes to improve our understanding of disease heterogeneity and develop therapies geared for each subtype of gastric cancer.

Methods: Fresh specimens obtained from resected primary or metastatic tumors under aseptic conditions. 1 g tumor samples injected SQ into flanks of NOD/SCID mice. Xenografts established after 5 passages and maintained by serial transplantation into new mice. Cell cultures established after 5 in vitro passages; cell lines after 15 passages.

Results: To date 26 tumor samples have been implanted from which 8 xenografts have been established. Table below summarizes the results. Cell line established from HER2-positive, trastuzumab refractory tumor resected from brain metastasis.

Conclusions: HER2-positive tumors have a favorable xenograft yield. Prior chemo or radiation therapy does not impact engraftment. Standard and experimental therapies are being tested on these xenografts to further validate difference in their biology and guide rational design of clinical trials.

[Table: see text]

124I-huA33 antibody uptake is driven by A33 antigen concentration in tissues from colorectal cancer patients imaged by immuno-PET

The primary aim of this analysis was to examine the quantitative features of antibody-antigen interactions in tumors and normal tissue after parenteral administration of antitumor antibodies to human patients.

METHODS

Humanized anti-A33 antibody (10 mg) labeled with the positron-emitting radionuclide (124)I ((124)I-huA33) was injected intravenously in 15 patients with colorectal cancer. Clinical PET/CT was performed approximately 1 wk later, followed by a detailed assay of surgically removed tissue specimens including radioactivity counting, autoradiography, immunohistochemistry, and antigen density determination.

RESULTS

PET/CT showed high levels of antibody targeting in tumors and normal bowel. In tissue specimens, the spatial distribution of (124)I-huA33 conformed to that of A33 antigen, and there was a linear relationship between the amount of bound antibody and antigen concentration. Antibody uptake was high in 1- to 2-mm regions of antigen-positive tumor cells (mean, ~0.05 percentage injected dose per gram) and in antigen-positive normal colonic mucosa (mean, ~0.03 percentage injected dose per gram). The estimated binding site occupancy for tumor and normal colon was 20%-50%.

CONCLUSION

The in vivo biodistribution of (124)I-huA33 in human patients 1 wk after antibody administration was determined by A33 antigen expression. Our data imply that the optimal strategy for A33-based radioimmunotherapy of colon cancer will consist of a multistep treatment using a radionuclide with short-range (α- or β-particle) emissions.