Staging of Gastric Cancer

Prognostic value of molecular cytology by one-step nucleic acid amplification (OSNA) assay of peritoneal washings in advanced gastric cancer patients

Peritoneal dissemination is a common form of gastric cancer (GC) recurrence, despite surgery with curative intent. This study aimed to evaluate the prognostic value of intraperitoneal lavage One-Step Nucleic Acid Amplification (OSNA) assay in advanced GC patients. OSNA assay targeting CK-19 mRNA was applied to detect free cancer cells (FCC) in intraperitoneal lavage samples obtained during gastrectomy. A total of 82 GC patients were enrolled to investigate the correlation between OSNA assay and patient's prognosis. Of the 82 patients, OSNA assay was positive in 25 (30.5%) patients. The median OS in OSNA positive patients was significantly lower than in OSNA negative patients (19 vs 45 months). Positive OSNA assay result was a significant unfavourable prognostic factor in both, univariable (HR 3.45, 95% CI 0.95-12.48; p = 0.0030) and multivariable analysis (HR 3.10, 95% CI 1.22-8.54; p = 0.0298). Positive OSNA assay in intraperitoneal lavage is a valuable indicator of poor survival in advanced GC patients after multimodal treatment. After further confirmation on larger sample size, OSNA assay of peritoneal washings could be considered an adjunct tool to conventional cytology, the current gold standard, to provide precise intraoperative staging and additional prognostic information.

Role of staging laparoscopy for gastric cancer patients

Staging laparoscopy (SL) is frequently carried out in patients with advanced gastric cancer. However, some clinical questions are being debated and consensus must be obtained. With this aim, a literature search of PubMed/MEDLINE was carried out using the keywords "gastric cancer," "SL," and "diagnostic laparoscopy". Articles published online up to February 2019 were analyzed, focusing on the following questions. (i) What is an adequate indication for SL? (ii) How do you carry out SL? (iii) Does SL provide accurate information about peritoneal dissemination? (iv) Is the yield of SL different by tumor location? (v) Is SL a safe procedure? (vi) Is "repeat SL" needed? (vii) Does SL provide oncological benefit? Results provided the following responses: (i) In Western countries, clinically resectable advanced tumor is an indication for SL. Terms to be introduced for adequate indication include "location," "type 4 (linitis feature)," "large tumor," "equivocal computed tomography (CT] findings," and "lymph node swelling". (ii) Exploration of the entire peritoneal cavity is preferable. (iii) Detection rate of peritoneal disease is 43%-52% in Japanese institutions and 7.8%-40% in other countries. False-negative findings during SL were 0%-17%, and 10%-13% when limited to cytology. (iv) Yield of SL was higher in gastric cancer compared with esophagogastric junctional tumor. (v) SL-related complications were estimated to occur in 0.4%. (vi) Repeat SL is important after treatment. (vii) If the efficacy of neoadjuvant chemotherapy for patients with P0CY1 is established, SL can provide oncological benefit. SL can be carried out safely and effectively. Considering the prevalence of neoadjuvant treatment, the role of SL will become more important.

The value of staging laparoscopy in gastric cancer

Treatment options for patients with gastric cancer (GC) are based on tumor staging and resectability. Although only surgery provides improved survival, resection is contraindicated and should be avoided in the presence of intra-abdominal disease stage M1 (liver, peritoneal, or non-local lymph node metastases). Thus, a detailed and precise evaluation is imperative for optimal treatment. Staging laparoscopy (SL) constitutes a major tool in the accurate diagnosis of several types of cancers, including GC. SL presents several critical advantages: it can diagnose intra-abdominal disease; serve as a complement to other imaging studies; allow for biopsies; facilitate intraoperative ultrasound evaluations; allow for sampling of peritoneal fluid for cytological examination; and serve as an option for the administration of intraperitoneal chemotherapy. Although considered and advocated as a very useful asset in the pre-treatment cancer-staging arsenal, the wider application of SL has been long debated. The purpose of our study was to evaluate the contribution of laparoscopy to GC staging.

Diagnostic accuracy of endoscopic ultrasonography (EUS) for the preoperative locoregional staging of primary gastric cancer

BACKGROUND

Endoscopic ultrasound (EUS) is proposed as an accurate diagnostic device for the locoregional staging of gastric cancer, which is crucial to developing a correct therapeutic strategy and ultimately to providing patients with the best chance of cure. However, despite a number of studies addressing this issue, there is no consensus on the role of EUS in routine clinical practice.

OBJECTIVES

To provide both a comprehensive overview and a quantitative analysis of the published data regarding the ability of EUS to preoperatively define the locoregional disease spread (i.e., primary tumor depth (T-stage) and regional lymph node status (N-stage)) in people with primary gastric carcinoma.

SEARCH METHODS

We performed a systematic search to identify articles that examined the diagnostic accuracy of EUS (the index test) in the evaluation of primary gastric cancer depth of invasion (T-stage, according to the AJCC/UICC TNM staging system categories T1, T2, T3 and T4) and regional lymph node status (N-stage, disease-free (N0) versus metastatic (N+)) using histopathology as the reference standard. To this end, we searched the following databases: the Cochrane Library (the Cochrane Central Register of Controlled Trials (CENTRAL)), MEDLINE, EMBASE, NIHR Prospero Register, MEDION, Aggressive Research Intelligence Facility (ARIF), ClinicalTrials.gov, Current Controlled Trials MetaRegister, and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), from 1988 to January 2015.

SELECTION CRITERIA

We included studies that met the following main inclusion criteria: 1) a minimum sample size of 10 patients with histologically-proven primary carcinoma of the stomach (target condition); 2) comparison of EUS (index test) with pathology evaluation (reference standard) in terms of primary tumor (T-stage) and regional lymph nodes (N-stage). We excluded reports with possible overlap with the selected studies.

DATA COLLECTION AND ANALYSIS

For each study, two review authors extracted a standard set of data, using a dedicated data extraction form. We assessed data quality using a standard procedure according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) criteria. We performed diagnostic accuracy meta-analysis using the hierarchical bivariate method.

MAIN RESULTS

We identified 66 articles (published between 1988 and 2012) that were eligible according to the inclusion criteria. We collected the data on 7747 patients with gastric cancer who were staged with EUS. Overall the quality of the included studies was good: in particular, only five studies presented a high risk of index test interpretation bias and two studies presented a high risk of selection bias.For primary tumor (T) stage, results were stratified according to the depth of invasion of the gastric wall. The meta-analysis of 50 studies (n = 4397) showed that the summary sensitivity and specificity of EUS in discriminating T1 to T2 (superficial) versus T3 to T4 (advanced) gastric carcinomas were 0.86 (95% confidence interval (CI) 0.81 to 0.90) and 0.90 (95% CI 0.87 to 0.93) respectively. For the diagnostic capacity of EUS to distinguish T1 (early gastric cancer, EGC) versus T2 (muscle-infiltrating) tumors, the meta-analysis of 46 studies (n = 2742) showed that the summary sensitivity and specificity were 0.85 (95% CI 0.78 to 0.91) and 0.90 (95% CI 0.85 to 0.93) respectively. When we addressed the capacity of EUS to distinguish between T1a (mucosal) versus T1b (submucosal) cancers the meta-analysis of 20 studies (n = 3321) showed that the summary sensitivity and specificity were 0.87 (95% CI 0.81 to 0.92) and 0.75 (95% CI 0.62 to 0.84) respectively. Finally, for the metastatic involvement of lymph nodes (N-stage), the meta-analysis of 44 studies (n = 3573) showed that the summary sensitivity and specificity were 0.83 (95% CI 0.79 to 0.87) and 0.67 (95% CI 0.61 to 0.72), respectively.Overall, as demonstrated also by the Bayesian nomograms, which enable readers to calculate post-test probabilities for any target condition prevalence, the EUS accuracy can be considered clinically useful to guide physicians in the locoregional staging of people with gastric cancer. However, it should be noted that between-study heterogeneity was not negligible: unfortunately, we could not identify any consistent source of the observed heterogeneity. Therefore, all accuracy measures reported in the present work and summarizing the available evidence should be interpreted cautiously. Moreover, we must emphasize that the analysis of positive and negative likelihood values revealed that EUS diagnostic performance cannot be considered optimal either for disease confirmation or for exclusion, especially for the ability of EUS to distinguish T1a (mucosal) versus T1b (submucosal) cancers and positive versus negative lymph node status.

AUTHORS' CONCLUSIONS

By analyzing the data from the largest series ever considered, we found that the diagnostic accuracy of EUS might be considered clinically useful to guide physicians in the locoregional staging of people with gastric carcinoma. However, the heterogeneity of the results warrants special caution, as well as further investigation for the identification of factors influencing the outcome of this diagnostic tool. Moreover, physicians should be warned that EUS performance is lower in diagnosing superficial tumors (T1a versus T1b) and lymph node status (positive versus negative). Overall, we observed large heterogeneity and its source needs to be understood before any definitive conclusion can be drawn about the use of EUS can be proposed in routine clinical settings.

Usefulness of staging laparoscopy for advanced gastric cancer

PURPOSE

The aim of this study was to clarify the usefulness of staging laparoscopy for planning the treatment strategy in patients with advanced gastric cancer.

METHODS

This was a retrospective study of patients with gastric cancer who underwent staging laparoscopy. The patients were divided into three groups according to the presence/absence of peritoneal metastasis (P) and positive peritoneal cytology (CY): P negative (0) CY0, P0CY positive (1), and P1CY1. The treatment strategy after staging laparoscopy was as follows: (1) surgery for the P0CY0 group, (2) surgery with neoadjuvant chemotherapy (NAC) for the P0CY1 group, and (3) chemotherapy for the P1CY1 group. Survival was estimated by the Kaplan-Meier method and statistical differences were analyzed by the log-rank test.

RESULTS

Thirty-four patients were included in this study: 11 in the P0CY0 group, 13 in the P0CY1 group, and 10 in the P1CY1 group. A gastrectomy was done in 11, 10, and no patients, respectively. The survival rate of the P0CY0 patients was significantly better than that of the P0CY1 or P1CY1 patients (P = 0.0106 and 0.0031, respectively).

CONCLUSION

Staging laparoscopy is useful for planning the treatment strategy and estimating the prognosis of patients with advanced gastric cancer.

Der laparoskopische Ultraschall

Laparoscopic ultrasound exploration has significantly augmented the range of minimally invasive surgery. In particular it is essential for 3D exploration of the abdomen for staging. Beyond its diagnostic, purposes laparoscopic ultrasound is gaining importance for intraoperative therapeutic support, e. g. imaging of the biliary tree during laparoscopic surgery of the bile duct and for navigation during radio-frequency ablative or resective interventions on the liver and other parenchymatous organs. Compared to other imaging procedures, sonography has still the highest potential for further development. The most progress can be expected in navigated ultrasound.

Preoperative Staging and Postoperative Surveillance for Gastric Cancer

Physicians must consider multiple factors when determining the most appropriate preoperative imaging strategy for gastric cancer. Health care resources are not unlimited, and the use of multiple expensive imaging techniques that do not alter treatment decisions is not recommended. With this in mind, EGD and CT scan alone should form the basis for preoperative evaluation, with further imaging considered only in selected cases. Based on the reviewed literature, we do not recommend routine surveillance imaging after curative surgery for gastric cancer. We agree with current NCCN guidelines that recommend history and physical examination every 4 to 6 months for 3 years, followed by yearly examinations. Imaging studies and endoscopy should be selectively performed in symptomatic patients.

Staginglaparoskopie in der Onkologie

The availability of more treatment options for gastrointestinal cancer requires precise and reliable pretherapeutic staging. Despite impressive technical progress in modern imaging procedures, this high level of staging quality is not yet warranted in all instances. Visual exploration of the abdominal cavity in extended diagnostic laparoscopy (EDL), including surgical dissection of areas which are primarily inaccessible, biopsy retrieval, and laparoscopic ultrasound, is superior in the diagnostic workup of early peritoneal carcinomatosis and (small) liver metastases. It is helpful to evaluate lymph node infliction and local resectability. In esophageal carcinoma, pretherapeutic EDL is valuable in case of advanced adenocarcinoma of the distal esophagus (AEG I according to Siewert), whereas the incidence of abdominal tumor manifestations in squamous cell carcinoma is too low to perform staging laparoscopy. In advanced gastric cancer, EDL yields relevant additional information in up to 20% of cases. If a multimodal therapeutic strategy is considered, EDL should be obligatory at least in prospective therapeutic studies. In carcinoma of the pancreas, EDL is in general not recommended by the majority of centers. Selective use (in particular in advanced cancer with a high probability of local irresectability) is gaining importance. In hepatobiliary malignancy including colorectal metastases, the high yield of additional information by EDL was confirmed in recent studies.

The role of surgery in patients with advanced gastric cancer

Surgery remains the mainstay of treatment with curative intent for established gastric cancer. Patient selection is critical to achieving satisfactory outcomes, and involves careful assessment of both patient fitness and disease stage. Staging techniques have multiplied and become much more sensitive in recent years. Current best practice involves a combination of spiral CT scan, Endoscopic ultrasound, PET scanning and laparoscopy. Only a minority of patients progress to potentially curative surgery after staging and fitness assessment in Western centres. Conventional treatment involves a distal subtotal gastrectomy or total gastrectomy depending on the site of the lesion. Innovative techniques include the Merendino operation, and pylorus and nerve sparing gastrectomies for earlier stage disease in the proximal and distal stomach, respectively. There is evidence of nutritional and quality of life benefit in the first 2 years after surgery from formation of a gastric substitute reservoir. Laparoscopic resection is well established in Japan and is developing rapidly elsewhere but its role and outcomes are not yet well defined. Radical lymph node dissection remains controversial: randomised trial evidence of overall benefit is lacking, but expert series have produced excellent results, and there are indications of a sub-group benefit for patients with stage II and III disease. The increased morbidity and mortality associated with radical dissection appear to be largely attributable to pancreatic and splenic resection together with limitations in Unit expertise. Surgical palliation has become less important in recent years as interventional radiology and endoscopy techniques have been developed for the same purposes. Overall mortality and survival results have improved dramatically over the last 20 years, but interpretation of these figures is made difficult by major changes in staging and case selection. The chances of long-term survival are, however, clearly much greater, and those of peri-operative death much less for an individual patient accepted for surgery in 2006 than they would have been in 1986.

Clinical significance of CT-defined minimal ascites in patients with gastric cancer

AIM: To study the clinical significance of minimal ascites, which was only defined by the CT and whose nature was not determined preoperatively, in the relationship with the peritoneal carcinomatosis.

METHODS: The medical records and the dynamic CT films of 118 patients with gastric cancer were reviewed. Factors associated with peritoneal carcinomatosis were analyzed in 40 patients who had CT-defined ascites of which the nature was surgically confirmed.

RESULTS: Only 12.5-25% of the CT-defined minimal ascites, whose volume was estimated to be less than 50 mL, were associated with peritoneal carcinomatosis. When the estimated CT-defined ascitic volume was 50 mL or more, peritoneal carcinomatosis was identified in 75–100%. When CT-defined lymph node enlargements were not found beyond the regional gastric area, perigastric invasions were not suspected, and the size of tumor was less than 3 cm, peritoneal carcinomatosis seemed significantly less accompanied at the univariate analysis. However, except for the minimal volume of CT-defined ascites in comparison with the mild or more, other factors were not confirmed multivariately.

CONCLUSION: In the patients with gastric cancer, CT-defined minimal ascites alone is rarely associated with peritoneal carcinomatosis, if it does not accompany other signs suggestive of malignant seeding. Therefore, consideration of active curative resection should not be hesitated, if CT-defined minimal ascites is the only delusive sign.

Multiorgan resection for gastric cancer: intraoperative and computed tomography assessment of locally advanced disease is inaccurate

Multiorgan resection of locally advanced gastric cancer has previously been associated with increased morbidity. This study was performed to determine the actual prevalence of pathologic T4 disease in multiorgan gastric resection specimens excised for presumed clinical T4 gastric cancer. A prospective oncology database was queried to identify gastric cancer patients who underwent en bloc multiorgan resection for clinical T4 lesions. Four hundred eighteen patients with gastric cancer underwent gastrectomy between 1990 and 2002. Multiorgan resection was performed in 21 of 418 (5%) patients. Multiorgan resection was not associated with a significant increase in morbidity or mortality. Pathologically confirmed T4 disease was present in only 8 of 21 (38%) patients; the pathologic T stage in all remaining patients was T3 (13 [62%]). Fifteen patients were evaluated by preoperative computed tomography scan. Preoperative computed tomography was inaccurate in assessing T4 lesions, with a positive predictive value of only 50%. Multiorgan resection was safely performed in patients with locally advanced gastric cancer. Pathologic T4 disease was present in only one third of multiorgan resections performed for en bloc excision of locally advanced gastric cancer. Improved methods for intraoperative assessment of disease extension to adjacent viscera should be investigated.

Staging laparoscopy for gastric cancer

Surgical resection remains the only potentially curative treatment of patients with gastric cancer. Evaluation of surgery and other treatments depends on accurate staging of the disease. The objective of the study was to compare staging laparoscopy with ultrasonography, endoscopic ultrasound, computed tomography, and histology for serosal infiltration, lymph node metastasis, peritoneal seeding, and hepatic metastasis. Diagnostic laparoscopy was carried out in 48 patients. Prelaparoscopic staging in all cases included upper gastrointestinal endoscopy and biopsies followed by endosonography, ultrasound, and computed tomography. Preoperative combined examination using CT and laparoscopy was superior when compared with each modality alone or the combinations of the other tests. The present study showed that preoperative evaluation of patients with laparoscopy is superior to all other diagnostic tests. We also found that laparoscopy and computed tomography were better in accurately assessing the serosal infiltration, peritoneal seeding, and hepatic metastases, which thus allows the surgeon to choose more effective treatment modality.