Increasing frequency of gene copy number aberrations is associated with immunosuppression and predicts poor prognosis in gastric adenocarcinoma.

BACKGROUND: Patients with Epstein-Barr virus-positive gastric cancers or those with microsatellite instability appear to have a favourable prognosis. However, the prognostic value of the chromosomal status (chromosome-stable (CS) versus chromosomal instable (CIN)) remains unclear in gastric cancer. METHODS: Gene copy number aberrations (CNAs) were determined in 16 CIN-associated genes in a retrospective study including test and validation cohorts of patients with gastric cancer. Patients were stratified into CS (no CNA), CINlow (1-2 CNAs) or CINhigh (3 or more CNAs). The relationship between chromosomal status, clinicopathological variables, and overall survival (OS) was analysed. The relationship between chromosomal status, p53 expression, and tumour infiltrating immune cells was also assessed and validated externally. RESULTS: The test and validation cohorts included 206 and 748 patients, respectively. CINlow and CINhigh were seen in 35.0 and 15.0 per cent of patients, respectively, in the test cohort, and 48.5 and 20.7 per cent in the validation cohort. Patients with CINhigh gastric cancer had the poorest OS in the test and validation cohorts. In multivariable analysis, CINlow, CINhigh and pTNM stage III-IV (P < 0.001) were independently associated with poor OS. CIN was associated with high p53 expression and low immune cell infiltration. CONCLUSION: CIN may be a potential new prognostic biomarker independent of pTNM stage in gastric cancer. Patients with gastric cancer demonstrating CIN appear to be immunosuppressed, which might represent one of the underlying mechanisms explaining the poor survival and may help guide future therapeutic decisions.

Development and validation of deep learning classifiers to detect Epstein-Barr virus and microsatellite instability status in gastric cancer: a retrospective multicentre cohort study.

BACKGROUND: Response to immunotherapy in gastric cancer is associated with microsatellite instability (or mismatch repair deficiency) and Epstein-Barr virus (EBV) positivity. We therefore aimed to develop and validate deep learning-based classifiers to detect microsatellite instability and EBV status from routine histology slides. METHODS: In this retrospective, multicentre study, we collected tissue samples from ten cohorts of patients with gastric cancer from seven countries (South Korea, Switzerland, Japan, Italy, Germany, the UK and the USA). We trained a deep learning-based classifier to detect microsatellite instability and EBV positivity from digitised, haematoxylin and eosin stained resection slides without annotating tumour containing regions. The performance of the classifier was assessed by within-cohort cross-validation in all ten cohorts and by external validation, for which we split the cohorts into a five-cohort training dataset and a five-cohort test dataset. We measured the area under the receiver operating curve (AUROC) for detection of microsatellite instability and EBV status. Microsatellite instability and EBV status were determined to be detectable if the lower bound of the 95% CI for the AUROC was above 0·5. FINDINGS: Across the ten cohorts, our analysis included 2823 patients with known microsatellite instability status and 2685 patients with known EBV status. In the within-cohort cross-validation, the deep learning-based classifier could detect microsatellite instability status in nine of ten cohorts, with AUROCs ranging from 0·597 (95% CI 0·522-0·737) to 0·836 (0·795-0·880) and EBV status in five of eight cohorts, with AUROCs ranging from 0·819 (0·752-0·841) to 0·897 (0·513-0·966). Training a classifier on the pooled training dataset and testing it on the five remaining cohorts resulted in high classification performance with AUROCs ranging from 0·723 (95% CI 0·676-0·794) to 0·863 (0·747-0·969) for detection of microsatellite instability and from 0·672 (0·403-0·989) to 0·859 (0·823-0·919) for detection of EBV status. INTERPRETATION: Classifiers became increasingly robust when trained on pooled cohorts. After prospective validation, this deep learning-based tissue classification system could be used as an inexpensive predictive biomarker for immunotherapy in gastric cancer. FUNDING: German Cancer Aid and German Federal Ministry of Health.

Spatial profiling of gastric cancer patient-matched primary and locoregional metastases reveals principles of tumour dissemination.

OBJECTIVE: Endoscopic mucosal biopsies of primary gastric cancers (GCs) are used to guide diagnosis, biomarker testing and treatment. Spatial intratumoural heterogeneity (ITH) may influence biopsy-derived information. We aimed to study ITH of primary GCs and matched lymph node metastasis (LNmet). DESIGN: GC resection samples were annotated to identify primary tumour superficial (PTsup), primary tumour deep (PTdeep) and LNmet subregions. For each subregion, we determined (1) transcriptomic profiles (NanoString 'PanCancer Progression Panel', 770 genes); (2) next-generation sequencing (NGS, 225 gastrointestinal cancer-related genes); (3) DNA copy number profiles by multiplex ligation-dependent probe amplification (MLPA, 16 genes); and (4) histomorphological phenotypes. RESULTS: NanoString profiling of 64 GCs revealed no differences between PTsup1 and PTsup2, while 43% of genes were differentially expressed between PTsup versus PTdeep and 38% in PTsup versus LNmet. Only 16% of genes were differently expressed between PTdeep and LNmet. Several genes with therapeutic potential (eg IGF1, PIK3CD and TGFB1) were overexpressed in LNmet and PTdeep compared with PTsup. NGS data revealed orthogonal support of NanoString results with 40% mutations present in PTdeep and/or LNmet, but not in PTsup. Conversely, only 6% of mutations were present in PTsup and were absent in PTdeep and LNmet. MLPA demonstrated significant ITH between subregions and progressive genomic changes from PTsup to PTdeep/LNmet. CONCLUSION: In GC, regional lymph node metastases are likely to originate from deeper subregions of the primary tumour. Future clinical trials of novel targeted therapies must consider assessment of deeper subregions of the primary tumour and/or metastases as several therapeutically relevant genes are only mutated, overexpressed or amplified in these regions.

Frequent Coamplification of Receptor Tyrosine Kinase and Downstream Signaling Genes in Japanese Primary Gastric Cancer and Conversion in Matched Lymph Node Metastasis.

OBJECTIVE: To establish the gene copy number status of receptor tyrosine kinase (RTK) and downstream signaling (DSS) genes genes in primary gastric cancer (primGC) and matched lymph node metastases (LNmet). BACKGROUND: Evidence suggests that coamplification between RTKs and DSSs and conversion between primGC and LNmet are associated with resistance to targeted therapy. METHODS: DNA from 237 Japanese primGC and 103 matched LNmet was analyzed using a newly developed multiplex ligation-dependent probe amplification (MLPA) probemix to investigate RTK (EGFR, HER2, FGFR2, and MET) and DSS (PIK3CA, KRAS, MYC, and CCNE1) gene copy number status. Results were compared between primGC and LNmet and related to clinicopathological data including survival. RESULTS: A total of 150 (63%) primGC had either RTK or DSS amplification. DSS coamplification was more frequent than RTK coamplification in primGC and LNmets. Moreover, 70 (30%) GC showed a disconcordant RTK and/or DSS gene copy number status between primGC and LNmet, most common was negative conversion for DSS genes (n=40 GC). The presence of RTK amplification in primGC was related to poorer survival in univariate analysis (P=0.04). CONCLUSIONS: This is the first and most comprehensive study in gastric cancer investigating the concordance between gene copy number status of targetable RTKs and downstream signaling oncogenes in primGC and LNmets. Future studies need to establish whether the relative high frequency of RTK and DSS coamplification and/or the relative high rate of negative conversion in LNmet can potentially explain recent failures of RTK targeted therapy in gastric cancer patients.

Biopsy proportion of tumour predicts pathological tumour response and benefit from chemotherapy in resectable oesophageal carcinoma: results from the UK MRC OE02 trial.

BACKGROUND: Neoadjuvant chemotherapy followed by surgery is the standard of care for UK patients with locally advanced resectable oesophageal carcinoma (OeC). However, not all patients benefit from multimodal treatment and there is a clinical need for biomarkers which can identify chemotherapy responders. This study investigated whether the proportion of tumour cells per tumour area (PoT) measured in the pre-treatment biopsy predicts chemotherapy benefit for OeC patients. PATIENTS AND METHODS: PoT was quantified using digitized haematoxylin/eosin stained pre-treatment biopsy slides from 281 OeC patients from the UK MRC OE02 trial (141 treated by surgery alone (S); 140 treated by 5-fluorouracil/cisplatin followed by surgery (CS)). The relationship between PoT and clinicopathological data including tumour regression grade (TRG), overall survival and treatment interaction was investigated. RESULTS: PoT was associated with chemotherapy benefit in a non-linear fashion (test for interaction, P=0.006). Only patients with a biopsy PoT between 40% and 70% received a significant survival benefit from neoadjuvant chemotherapy (N=129; HR (95%CI):1.94 (1.39-2.71), unlike those with lower or higher PoT (PoT<40%, N=39, HR:1.25 (0.66-2.35); PoT>70% (N=28, HR:0.65 (0.36-1.18)). High pre-treatment PoT was related to lack of primary tumour regression (TRG 4 or 5), P=0.0402. CONCLUSIONS: This is the first study to identify in a representative subgroup of OeC patients from a large randomized phase III trial that the proportion of tumour in the pre-chemotherapy biopsy predicts benefit from chemotherapy and may be a clinically useful biomarker for patient treatment stratification.Proportion of tumour is a novel biomarker which can be measured in the pre-treatment diagnostic biopsy and which may enable the identification of chemotherapy responders and non-responders among patients with oesophageal carcinoma. Proportion of tumour could easily become part of the routine reporting of oesophageal cancer biopsies and may aid in managing patients with borderline resectable cancer.

The survival difference between gastric cancer patients from the UK and Japan remains after weighted propensity score analysis considering all background factors.

BACKGROUND: Previous studies comparing survival between gastric cancer (GC) patients from the West and the East were based on the assumption that background factors and prognostic factors were identical. The aim of the current study was to compare the survival of GC patients from the UK and Japan using weighted propensity score analysis after identifying all different background factors. METHODS: Data from 464 patients from the Leeds Teaching Hospital NHS Trust, Leeds, UK (LTHT), and 465 patients from the Kanagawa Cancer Center Hospital, Yokohama, Japan (KCCH), who had surgery for GC were analyzed. Prognostic factors for overall survival (OS) and cancer-specific survival (CSS) were identified by univariate and multivariate analyses. Survival was compared by propensity score weighting after adjusting for all significantly different background factors. RESULTS: Most background factors were different between LTHT and KCCH patients. Unadjusted stage-specific OS and CSS were significantly better in KCCH. Independent prognostic factors for unadjusted OS and CSS were pT and pN in KCCH and in addition tumor location, pancreatectomy, resection margin status and number of examined lymph nodes in LTHT. Even after adjusting for all background characteristics, survival remained better in KCCH. CONCLUSIONS: These results suggest that differences in background factors are unable to fully explain the survival difference of GC patients between UK and Japan. Comprehensive studies into the biology of GC and/or host factors are needed to fully understand the survival difference.

Systematic review of definitions of failure in revisional bariatric surgery.

BACKGROUND: There are no agreed definitions as to what constitutes a 'failure' of the primary bariatric procedure in relation to weight loss. METHODS: The MEDLINE database for primary research articles was searched using obesity [title] or bariatric [title] and revision [title] or revisional [title]. RESULTS: The MEDLINE search retrieved 174 studies. After duplicates and exclusions were removed, 60 articles underwent analysis. Fifty-one studies included inadequate weight loss or weight regain as an indication for revision: 31/51 (61 %) gave no definition of failure, 7/20 quoted <50 % of excess weight loss at 18 months and 6/20 used <25 % excess weight loss. CONCLUSIONS: The majority of published studies do not define failure of bariatric surgery, and <50 % excess weight loss at 18 months was the most frequent definition identified.

The superiority of the seventh edition of the TNM classification depends on the overall survival of the patient cohort: comparative analysis of the sixth and seventh TNM editions in patients with gastric cancer from Japan and the United Kingdom.

BACKGROUND: The objective of this study was to investigate whether the seventh edition of the American Joint Committee on Cancer/International Union Against Cancer TNM classification (TNM7) had superior discriminatory ability over the sixth edition of the TNM classification (TNM6) in patients with gastric cancer regardless of their country of origin. METHODS: In total, 538 patients from the Kanagawa Cancer Center Hospital (Yokohama, Japan) (KCCH) and 519 patients from the Leeds Teaching Hospitals National Health Service Trust (Leeds, United Kingdom) (LTHT) who underwent surgery for gastric cancer were selected. Overall survival was used for statistical analysis. Hazard ratios (HRs) were estimated with disease stage as a continuous variable to evaluate the discriminatory ability of the TNM stage groups. The estimates of log HRs (logHRs) for the TNM6 and the TNM7 stage groups were compared. RESULTS: In the KCCH cohort, 82 patients (15%) were upstaged, and 26 patients (5%) were downstaged between TNM6 and TNM7 compared with 253 patients (49%) and 53 patients (10%), respectively, in the LTHT cohort. The logHRs for a 1-stage increase within TNM6 and TNM7 were 1.06 and 1.16, respectively, in the KCCH cohort and 0.57 and 0.79, respectively, in the LTHT cohort. The differences in logHRs between TNM6 and TNM7 were significant in each cohort (KCCH: logHR, 0.11; P = .024; LTHT: logHR, 0.21; P = .0002) and between the 2 cohorts. CONCLUSIONS: TNM7 had superior discriminatory ability compared with TNM6 in both cohorts. The improved ability to discriminate patients with different survival probability when using TNM7 was greater in the LTHT cohort. The current findings indicated that the discriminatory ability of the TNM stage groups may depend on the baseline survival characteristics of the patient cohort.

Significant variation of resected meso-esophageal tissue volume in two-stage subtotal esophagectomy specimens: a retrospective morphometric study.

BACKGROUND: Differences in the extent and quality of surgical resection for esophageal cancer may influence the pathological staging and patient outcome. There are no data in the literature qualitatively and/or quantitatively characterizing esophagectomy specimens. METHODS: Macroscopic images of 161 esophagectomy specimens were analyzed retrospectively. The extent of resection was qualitatively classified as "muscularis propria," "intra-meso-esophageal," or "meso-esophageal." The volume of meso-esophageal tissue was quantified morphometrically. The number of muscle defects per specimen was counted. Results were related to clinicopathological variables, including survival. RESULTS: Sixty-two (39%) specimens were classified as "muscularis propria," 65 (40%) as "intra-meso-esophageal," and 34 (21%) as "meso-esophageal." The morphometrically measured meso-esophageal tissue volume was different between the three types (P < 0.001). The specimen type was related to the total number of lymph nodes (P = 0.02), number of metastatic lymph nodes (P = 0.024), and depth of tumor invasion (P = 0.013), but not related to extramural tumor volume, circumferential resection margin status, or the surgeon performing the resection. The number of muscle defects per specimen was similar in all resection types. The resection specimen classification was related to survival in patients treated by surgery alone (P = 0.027). CONCLUSIONS: This is the first study to quantify and classify the volume of tissue resected during esophagectomy. Our study shows significant variation of the resected tissue volume impacting pathological tumor staging. This variation was not associated with individual surgeon performance. A prospective, multicenter study is needed to validate our results and to investigate the potential biological mechanisms influencing the resectable volume of meso-esophageal tissue in cancer patients.

Prognostic significance of cancer within 1 mm of the circumferential resection margin in oesophageal cancer patients following neo-adjuvant chemotherapy.

OBJECTIVES: The prognostic significance of the circumferential resection margin (CRM) status in oesophageal cancer patients treated with neo-adjuvant chemotherapy and radical resection is controversial. Furthermore, it is currently unclear whether patients with cancer located at the CRM have a prognosis different from that of those with cancer within 1 mm of the CRM. This is the first study aiming to establish the optimal tumour-free distance from the CRM of an oesophagectomy in patients who have undergone neo-adjuvant chemotherapy. METHODS: The clinicopathological data of 232 oesophageal cancer patients from two UK centres were analysed. The CRM status was classified as Group A (cancer at the CRM), Group B (cancer within 1 mm but not at the CRM) and Group C (no cancer within 1 mm from the CRM). The relationship between the CRM status and patient survival was investigated. RESULTS: Thirty-eight specimens were classified as Group A, 89 as Group B and 105 as Group C. CRM status was related to the depth of tumour invasion (P < 0.001) and lymph node status (P < 0.001). The prognoses of the Group A and the Group B patients were similar. Both were poorer than that of the Group C patients (P = 0.008). Lymph node status was the only independent prognostic marker in multivariate analysis. CONCLUSIONS: Oesophageal cancer patients treated with preoperative chemotherapy with cancer cells at the CRM or within 1 mm of the CRM of the resected specimen have a significantly worse survival than patients with no cancer cells within 1 mm of the margin. However, this study suggests that the overall prognostic significance of the CRM status is limited in this cohort and the postoperative lymph node status is the most important prognostic factor in oesophageal cancer patients treated with neo-adjuvant chemotherapy and surgery.

Comparison of early outcomes for laparoscopic ventral hernia repair between nonobese and morbidly obese patient populations.

BACKGROUND: Obesity predisposes to incisional herniation and increased the incidence of recurrence after conventional open repair. Only sparse data on the safety and security of laparoscopic ventral hernia repair (LVHR) for morbidly obese patients are available. This study compared the incidence of perioperative complications and early recurrence after LVHR between morbidly obese and non-morbidly obese patients. METHODS: The case records of consecutive patients who underwent LVHR between December 2002 and August 2007 were reviewed. Patients with a body mass index (BMI) lower than 35 kg/m2 were compared with morbidly obesity patients who had a BMI of 35 kg/m2 or higher. RESULTS: The study included 168 patients (87 men) with a median age of 55 years (range, 24-92 years). Two conversions to open repair (1.2%) were performed, both for non-morbidly obese patients. Of the 168 patients, 42 (25%) were morbidly obese (BMI range, 35.0-58.0 kg/m2) and 126 (75%) were non-morbidly obese (BMI range, 15.5-34.9 kg/m2). The groups showed no significant differences in age, gender, number or size of fascial defects, operative time, length of hospital stay, or incidence of perioperative complications. At a median follow-up period of 19 months (range, 6-62 months), 20 patients (12%) had recurrent hernias. The incidence of recurrence was significantly associated with the size of the fascial defect and the size of the mesh, but not with morbid obesity. CONCLUSION: No significant difference in the incidence of perioperative complications or recurrence after LVHR was observed between the morbidly obese patients and the non-morbidly obese patients.

Total laparoscopic pancreaticoduodenectomy and reconstruction for a cholangiocarcinoma of the bile duct.

BACKGROUND: In this paper, we report on our experience with a totally laparoscopic pancreatico-duodenectomy performed for a cholangiocarcinoma of the lower third of the bile duct. METHODS: The patient was placed in the steep reverse Trendelenberg, Lloyd-Davis position. The procedure was performed with six laparoscopic ports, using similar steps to the open approach, with the use of an ultrasonic cutting and coagulating instrument for dissection and endoscopic linear stapling devices for the bile duct, intestinal, and gastroduodenal artery division. Reconstruction was done on a single loop by an intracorporeally sutured pancreaticojejunostomy, hepaticojejunostomy, and a stapled gastroenterostomy. The resection specimen was placed in a bag and retrieved through a 5-cm Pfannenstiel incision. RESULTS: Histology confirmed a T3 N1 R0 cholangiocarcinoma with the involvement of 1 of 17 lymph nodes. Twelve months following surgery, he remains well, having completed a course of adjuvant chemotherapy. CONCLUSIONS: Although the operation was technically demanding, it can be safely performed with a good oncologic result.

Analysis of illness behavior in patients after "failed" antireflux surgery.

HYPOTHESIS: Patients complaining of problems after antireflux surgery may have differences in illness behavior that could influence the decision to perform a revision procedure or its outcome. DESIGN: A prospective comparative questionnaire survey of consecutive series of patients. SETTING: University teaching hospital. PATIENTS: Those undergoing esophageal pH and manometric studies from July 1, 2001, through July 1, 2004, for investigation of new or recurrent symptoms after previous antireflux surgery. There were 52 eligible patients, of whom 4 were excluded because of refusal to enter the study (n = 1) or communication difficulties (n = 3). Of the remaining 48 patients, 22 underwent revision surgery and 26 did not. These 2 groups were compared with 167 patients with primary gastroesophageal reflux disease investigated during the same period. INTERVENTION: Self-administered, validated illness behavior questionnaire completed after informed consent was obtained. MAIN OUTCOME MEASURES: Illness behavior categories derived from the questionnaire answers: general hypochondriasis, disease conviction, psychological vs somatic illness perception, affective inhibition, affective disturbance, denial, irritability, Whiteley index of hypochondriasis, affective state, and disease affirmation. RESULTS: There were no significant differences in illness behavior category scores between the 2 groups with postoperative problems and patients with primary gastroesophageal reflux disease. CONCLUSION: Patients with problems after antireflux surgery have an illness behavior profile similar to that in patients with primary gastroesophageal reflux disease irrespective of whether there is objective evidence of recurrent reflux disease.