Extension of resection after positive intraoperative pathology during surgery for gastric and gastroesophageal junction adenocarcinoma: a retrospective cohort study.

BACKGROUND: Residual tumor at the resection margins after surgery for gastric and gastroesophageal junction (GEJ) adenocarcinoma is a known prognostic factor. In this single-center, retrospective cohort study in a tertiary referral center, the authors aimed to evaluate the relevance of intraoperative pathology consultation (IOC) and consecutive extension of surgery on patient survival. STUDY DESIGN: Of 737 consecutive patients undergoing (sub)total gastrectomy for gastric or GEJ adenocarcinoma, 679 cases with curative intent surgery between 05/1996 and 03/2019 were included. Patients were categorized into: R0 without further resection (direct R0), R0 after positive IOC and extension of resection (converted R0), and R1. RESULTS: IOC was performed in 242 (35.6%) patients, in 216 (89.3%) at the proximal resection margin. Direct R0-status was achieved in 598 (88.1%), converted R0 in 26 (3.8%) of 38 (5.6%) patients with positive IOC and R1 in 55 (8.1%) patients. The median follow-up was 29 months for surviving patients. 3-year survival rate (3-YSR) was significantly higher for direct R0 compared to converted R0 with 62.3% compared to 21.8% (hazard ratio=0.298; 95% CI=0.186-0.477, P <0.001). 3-YSR was similar between converted R0 and R1 (21.8 vs. 13.3%; hazard ratio =0.928; 95% CI=0.526-1.636, P =0.792). In multivariate analysis, advanced T ( P <0.001), N ( P <0.001), R ( P =0.003), and M1 status ( P <0.001) were associated with worse overall survival. CONCLUSION: IOC and consecutive extended resection for positive resection margins in gastrectomy for the proximal gastric and GEJ adenocarcinoma does not achieve long-term survival benefits in advanced tumor stages.

Two decades of gastric and gastroesophageal junction cancer surgery.

PURPOSE: Diagnosis and treatment of gastric and gastroesophageal junction cancer have undergone many critical changes during the last two decades. We addressed the question of how clinical reality outside of clinical trials has changed for gastric and gastroesophageal junction cancer patients in a European center for upper gastrointestinal surgery. METHODS: In this retrospective cohort study, patients undergoing (sub)total gastrectomy for gastric or gastroesophageal junction adenocarcinoma between 1996 and 2017 in a tertiary upper gastrointestinal center were included. The time was divided into a) before (1996-2006) (pre-CTx) and b) after (2006-2017) (CTx) the MAGIC trial. Data were comprehensively analyzed for demographics, tumor stage, perioperative treatment, surgery, histopathology, and survival rates (SR). RESULTS: 737 patients (32% female) underwent gastrectomy, 255 patients in the pre-CTx era and 482 patients in the CTx era. The median age was 65 years and the median follow-up was 27.5 months for surviving patients. Around 16.9% of patients received neoadjuvant treatment in the pre-CTx era versus 46.3% in the CTx era. The 3-year survival rate (3-YSR) was 46.4% in the pre-CTx and 60.9% in the CTx era (p < 0.001). For pretreated patients, 3-YSR was 39.0% (pre-CTx) versus 55.3% (CTx) (p = 0.168). Survival rate (SR) for locally advanced tumor stages (cT3/cT4) was higher when neoadjuvant therapy was administered (3-YSR: 56.7% vs 40.6%; p = 0.022). There were no significant differences according to sex (p = 0.357), age (p = 0.379), pT category (p = 0.817), pN stage (p = 0.074), cM stage (p = 0.112), Laurén classification (p = 0.158), and SRs (3-YSR: 60.3% vs 59.4%; p = 0.898) between the MAGIC and FLOT regimens. CONCLUSIONS: Survival rates have dramatically improved for gastric cancer patients during the last two decades. MAGIC and FLOT regimens showed similar results in the postsurgical follow-up.

Microsatellite instability and sex differences in resectable gastric cancer - A pooled analysis of three European cohorts.

OBJECTIVE: Biological sex differences in cancer are increasingly acknowledged. Here, we examined these differences in clinicopathological characteristics and survival in microsatellite instability (MSI)-high and microsatellite stable (MSS) gastric cancer (GC). DESIGN: We analysed MSI status by polymerase chain reaction (PCR) and/or mismatch repair (MMR) status by immunohistochemistry in a pooled analysis of individual patient data from one retrospective cohort from Cologne, and the randomised phase III clinical trials D1/D2 and CRITICS. All patients had resectable adenocarcinoma of the stomach and/or gastro-oesophageal junction. Patients were treated with either surgery only or perioperative chemo(radio)therapy. RESULTS: MSI and/or MMR analyses on 1307 tumours resulted in 1192 (91.2%) MSS and/or MMR proficient (MMRP) [median age, 65 years; 759 males (63.7%); 619 treated with surgery only (51.9%)], and 115 (8.8%) MSI-high [median age, 69 years; 67 males (58.3%); 76 treated with surgery only (66.1%)] GC cases. Males had shorter overall survival (OS) than female MSI-high GC (5-year OS 34.7% vs. 69.7%; hazard ratio (HR) 2.68, 95%CI 1.60 to 4.49; p < 0.001). Females with MSI-high had longer OS than those with MSS/MMRP GC (HR 0.61, 95%CI 0.41 to 0.92; p = 0.02). Males with MSI-high did not have longer OS than those with MSS/MMRP GC (HR 1.26, 95%CI 0.94 to 1.69; p = 0.12). CONCLUSIONS: MSI-high GC males had a significantly worse prognosis compared to their female counterparts in three independent cohorts. In addition, the favourable prognostic value of MSI was only seen in females and not in males. These observations emphasise the need to consider sex differences in prognosis and treatment effects in oncology. CLINICAL TRIAL REGISTRATION: The CRITICS trial is registered at ClinicalTrials.gov, number NCT00407186; EudraCT, number 2006-004130-32; and CKTO, 2006-02.

Occurrence of High Microsatellite-Instability/Mismatch Repair Deficiency in Nearly 2,000 Human Adenocarcinomas of the Gastrointestinal Tract, Pancreas, and Bile Ducts: A Study From a Large German Comprehensive Cancer Center.

INTRODUCTION: Knowledge of the high microsatellite-instability (MSI-H)/mismatch repair deficiency (MMRd) status is of increasing interest for personalized neoadjuvant or adjuvant therapy planning. Only a few studies are available on MSI-H distribution in the Northern European Caucasian patient population. In this study, we focused on a large cohort of tumors of the upper gastrointestinal tract. MATERIALS AND METHODS: Surgical material from a total of 1,965 patients was analyzed for MSI-H/MMRd status (including 1,267 carcinomas of the esophagus or stomach). All tumors were analyzed with an internationally recommended immunohistochemical panel consisting of four antibodies (MLH1, MSH2, PMS2, and MSH6). The results were molecularly objectified. RESULTS: Adenocarcinomas with MSI-H/MMRd were detected with the following distribution: esophagus (1.4%), stomach (8.3%), small intestine (18.2%), large intestine (8.5%), intrahepatic bile ducts (1.9%), and pancreas (0%). In case of gastric tumors with MSI-H/MMRd, neoadjuvant therapy did not influence the prognosis of patients (p = 0.94). Within all tumor entities with MSI-H/MMRd, patients with a UICC stage 4 were also represented. In this advanced stage, 11.7% of patients with MSS tumors were diagnosed compared to 0.5% of patients with MSI-H tumors relative to the entire tumor collective. DISCUSSION: In this study, the proportion of MSI-H/MMRd tumors in the stomach is smaller than would have been expected in knowledge of the data published by TCGA or AGRC. Negative prognostic effects regarding MSI-H status and neoadjuvant therapy as described by the MAGIC study group were not seen in our cohort. The extent to which the MSI-H/MMRd status should be known for neoadjuvant therapy planning must be clarified in prospective studies in the future. At present, there is no convincing data to dispense the neoadjuvant therapy for gastric carcinoma. Due to the very convincing, positive data regarding the response rates of MSI-H tumors to treatment with PD1/PD-L1 inhibitors, every metastatic carcinoma of the gastrointestinal tract should be tested for its MSI-H status.

Sex-specific prognostic effect of CD66b-positive tumor-infiltrating neutrophils (TANs) in gastric and esophageal adenocarcinoma.

BACKGROUND: Tumor-associated neutrophils (TANs) have recently been identified as a relevant component of the tumor microenvironment (TME) in solid tumors. Within the TME TANs mediate either tumor-promoting or tumor-inhibiting activities. So far, their prognostic relevance remains to be determined. This study aims to evaluate the prognostic relevance of TANs in different molecular subtypes of gastric and esophageal adenocarcinoma. METHODS: We analyzed a total of 1118 Caucasian patients divided into gastric adenocarcinoma (n = 458) and esophageal adenocarcinoma cohort (n = 660) of primarily resected and neoadjuvant-treated individuals. The amount of CD66b + TANs in the tumor stroma was determined using quantitative image analysis and correlated to both molecular, as well as clinical data. RESULTS: An accumulation of TANs in the tumor stroma of gastric carcinomas was associated to a significant favorable prognosis (p = 0.026). A subgroup analysis showed that this effect was primarily related to the molecular chromosomal instable subtype (CIN) of gastric carcinomas (p = 0.010). This was only observed in female patients (p = 0.014) but not in male patients (p = 0.315). The same sex-specific effect could be confirmed in adenocarcinomas of the esophagus (p = 0.027), as well as in female individuals after receiving neoadjuvant therapy (p = 0.034). CONCLUSIONS: Together, we show a sex-specific prognostic effect of TANs in gastric cancer within a Caucasian cohort. For the first time, we showed that this sex-specific prognostic effect of TANs can also be seen in esophageal cancer.

Optimized PD-L1 scoring of gastric cancer.

BACKGROUND: PD-1/PD-L1-Immunotherapy has been approved for gastric carcinoma. PD-L1 assessment by immunohistochemistry is the principle biomarker. Are biopsies able to map the actual PD-L1 status of the entire tumor? METHODS: Whole tumor slides of 56 gastric carcinoma were analyzed to determine the distribution of PD-L1 positive cells in the entire tumor areas. Tissue micro arrays with four cores of the tumor surface, which represents the endoscopically accessible biopsy zone, were built from the same tumors. The PD-L1 CPS value was determined separately for each core. Preoperative diagnostic biopsies were available for 22 of the tumors. PD-L1 prevalence, sensitivity and specificity were analyzed using the whole tumor slides as reference scores. Molecular subtyping was performed and related to the PD-L1 status. RESULTS: 27.3% of cases were PD-L1 negative (CPS < 1), 43.6% showed low PD-L1 expression (CPS ≥ 1 to < 5), 12.7% moderate (CPS ≥ 5 to < 10) and 16.4% strong expression (CPS ≥ 10). The biopsies showed best test characteristics if four surface biopsies were analyzed combined, i.e., the CPS was calculated across all four biopsies. The prevalence showed a distribution similar to the resection specimens, sensitivity was 0.73 and specificity 1.0. Using fewer surface biopsies decreased sensitivity and specificity and caused false-negative classifications. Compared to the TMAs, the preoperative biopsies showed reduced sensitivity (0.412). CONCLUSIONS: This is the first comprehensive study to optimize PD-L1 assessment in gastric cancer using endoscopically available tissue. The obtained PD-L1 prevalence is consistent with data of current clinical studies. Calculation of the test characteristics shows that surface biopsies can be indicative of the true PD-L1 status based on the resection specimen. However, an adequate number of biopsies is required. In this study, n = 4 biopsies yielded best results.

Amplification of KRAS and its heterogeneity in non-Asian gastric adenocarcinomas.

BACKGROUND: Gastric cancer is one of the deadliest cancer entities worldwide. While surgery is the only curative treatment option in early tumors, for locally advanced and metastatic patients further therapeutic targets are needed. Several studies not only reported mutations but also amplifications of the KRAS locus in different cancer entities. More recently, KRAS amplification was discussed as a new therapeutic target. Little is known about the (prognostic) relevance and (heterogenic) distribution of KRAS amplification in gastric adenocarcinomas, especially in Non-Asian patients. METHODS: Amplification of the KRAS locus and corresponding protein expression was analyzed in 582 gastric adenocarcinomas employing fluorescence in-situ hybridization (FISH) and immunohistochemistry. Amplification status was correlated with clinico-pathological features, clinical outcome and molecular tumor data including a correlation to the TCGA subtypes of gastric carcinoma. RESULTS: KRAS amplification was detected in 27 out of 470 analysable tumors (5.7%) and correlated with protein expression of KRAS in all amplified tumors. Within the KRAS amplified gastric tumors 14/27 (51.9%) showed a heterogeneous distribution with also KRAS non-amplified tumor parts. According to TCGA 24 tumors (88.8%) were related to chromosomal instable tumors (CIN). The survival analysis of the entire patient cohort did not show any difference in overall survival in dependence on the KRAS status. However, a significant survival difference with a worse outcome for patients with KRAS amplified tumors was identified when analysing patients without neoadjuvant pre-treatment. CONCLUSIONS: We confirm the unfavorable prognosis of KRAS amplified tumors reported by other studies in (Asian) patient groups, at least in patients without neoadjuvant pre-treatment. Within KRAS amplified tumors we revealed intratumoral heterogeneity that may define a (more aggressive) tumor cell population which is more frequently observed in patients with lymph node metastases. Despite the heterogeneous distribution of KRAS amplified tumor clones, KRAS amplified locally advanced or metastasized gastric adenocarcinomas represent a therapeutically highly relevant tumor subgroup.