Prevalence of False-Negative Results of Intraoperative Consultation on Surgical Margins During Resection of Gastric and Gastroesophageal Adenocarcinoma

Surgical Techniques and Related Perioperative Outcomes After Robot-assisted Minimally Invasive Gastrectomy (RAMIG): Results From the Prospective Multicenter International Ugira Gastric Registry

OBJECTIVE

To gain insight into the global practice of robot-assisted minimally invasive gastrectomy (RAMIG) and evaluate perioperative outcomes using an international registry.

BACKGROUND

The techniques and perioperative outcomes of RAMIG for gastric cancer vary substantially in the literature.

METHODS

Prospectively registered RAMIG cases for gastric cancer (≥10 per center) were extracted from 25 centers in Europe, Asia, and South-America. Techniques for resection, reconstruction, anastomosis, and lymphadenectomy were analyzed and related to perioperative surgical and oncological outcomes. Complications were uniformly defined by the Gastrectomy Complications Consensus Group.

RESULTS

Between 2020 and 2023, 759 patients underwent total (n=272), distal (n=465), or proximal (n=22) gastrectomy (RAMIG). After total gastrectomy with Roux-en-Y-reconstruction, anastomotic leakage rates were 8% with hand-sewn (n=9/111) and 6% with linear stapled anastomoses (n=6/100). After distal gastrectomy with Roux-en-Y (67%) or Billroth-II-reconstruction (31%), anastomotic leakage rates were 3% with linear stapled (n=11/433) and 0% with hand-sewn anastomoses (n=0/26). Extent of lymphadenectomy consisted of D1+ (28%), D2 (59%), or D2+ (12%). Median nodal harvest yielded 31 nodes (interquartile range: 21-47) after total and 34 nodes (interquartile range: 24-47) after distal gastrectomy. R0 resection rates were 93% after total and 96% distal gastrectomy. The hospital stay was 9 days after total and distal gastrectomy, and was median 3 days shorter without perianastomotic drains versus routine drain placement. Postoperative 30-day mortality was 1%.

CONCLUSIONS

This large multicenter study provided a worldwide overview of current RAMIG techniques and their respective perioperative outcomes. These outcomes demonstrated high surgical quality, set a quality standard for RAMIG, and can be considered an international reference for surgical standardization.

Artificial intelligence-based real-time histopathology of gastric cancer using confocal laser endomicroscopy

There has been a persistent demand for an innovative modality in real-time histologic imaging, distinct from the conventional frozen section technique. We developed an artificial intelligence-driven real-time evaluation model for gastric cancer tissue using confocal laser endomicroscopic system. The remarkable performance of the model suggests its potential utilization as a standalone modality for instantaneous histologic assessment and as a complementary tool for pathologists' interpretation.

Advances in Gastric Cancer Surgical Management

The goal of a gastric cancer operation is a microscopically negative resection margin and D2 lymphadenectomy. Minimally invasive techniques (laparoscopic and robotic) have been proven to be equivalent for oncologic care, yet with faster recovery. Endoscopic mucosal resection can be used for T1a N0 tumor resection. Better understanding of hereditary gastric cancer and molecular subtypes has led to specialized recommendations for MSI-high tumors and patients with pathogenic CDH1 mutations. In the future, surgical management will support minimally invasive approaches and personalized cancer care based on subtype.

Real-time Histological Evaluation of Gastric Cancer Tissue by Using a Confocal Laser Endomicroscopic System

BACKGROUND/AIM

The need for instant histological evaluation of fresh tissue, especially in cancer treatment, remains paramount. The conventional frozen section technique has inherent limitations, prompting the exploration of alternative methods. A recently developed confocal laser endomicroscopic system provides real-time imaging of the tissue without the need for glass slide preparation. Herein, we evaluated its applicability in the histologic evaluation of gastric cancer tissues.

MATERIALS AND METHODS

A confocal laser endomicroscopic system (CLES) with a Lissajous pattern laser scanning, was developed. Fourteen fresh gastric cancer tissues and the same number of normal gastric tissues were obtained from advanced gastric cancer patients. Fluorescein sodium was used for staining. Five pathologists interpreted 100 endomicroscopic images and decided their histologic location and the presence of cancer. Following the review of matched hematoxylin and eosin (H&E) slides, their performance was evaluated with another 100 images.

RESULTS

CLES images mirrored gastric tissue histology. Pathologists were able to detect the histologic location of the images with 65.7% accuracy and differentiate cancer tissue from normal with 74.7% accuracy. The sensitivity and specificity of cancer detection were 71.9% and 76.1%. Following the review of matched H&E images, the accuracy of identifying the histologic location was increased to 92.8% (p<0.0001), and that of detecting cancer tissue was also increased to 90.9% (p<0.001). The sensitivity and specificity of cancer detection were enhanced to 89.1% and 93.2% (p<0.0001).

CONCLUSION

High-quality histological images were immediately acquired by the CLES. The operator training enabled the accurate detection of cancer and histologic location raising its potential applicability as a real-time tissue imaging modality.

The correlation between the margin of resection and prognosis in esophagogastric junction adenocarcinoma

Adenocarcinoma of the gastroesophageal junction (AEG) has become increasingly common in Western and Asian populations. Surgical resection is the mainstay of treatment for AEG; however, determining the distance from the upper edge of the tumor to the esophageal margin (PM) is essential for accurate prognosis. Despite the relevance of these studies, most have been retrospective and vary widely in their conclusions. The PM is now widely accepted to have an impact on patient outcomes but can be masked by TNM at later stages. Extended PM is associated with improved outcomes, but the optimal PM is uncertain. Academics continue to debate the surgical route, extent of lymphadenectomy, preoperative tumor size assessment, intraoperative cryosection, neoadjuvant therapy, and other aspects to further ensure a negative margin in patients with gastroesophageal adenocarcinoma. This review summarizes and evaluates the findings from these studies and suggests that the choice of approach for patients with adenocarcinoma of the esophagogastric junction should take into account the extent of esophagectomy and lymphadenectomy. Although several guidelines and reviews recommend the routine use of intraoperative cryosections to evaluate surgical margins, its generalizability is limited. Furthermore, neoadjuvant chemotherapy and radiotherapy are more likely to increase the R0 resection rate. In particular, intraoperative cryosections and neoadjuvant chemoradiotherapy were found to be more effective for achieving negative resection margins in signet ring cell carcinoma.

SMPDL3B contributes to gastric adenocarcinoma cells progression by promoting the infiltration of M2 macrophages

Background/aim

The common disease gastric adenocarcinoma (GAC) has a high morbidity and mortality, so there is an urgent need for research to explore new diagnostic markers and therapeutic targets. This investigation was carried out to investigate the expression of sphingomyelin phosphodiesterase acid-like 3b (SMPDL3B) in GAC and its effects on tumor progression.

Materials and methods

Samples were collected from patients who underwent radical gastrectomy from January 2021 to December 2022. Along with the normal gastric epithelial cell lines GES-1 and SGC-7901, the AGS, MGC-803, and MSN-45 human gastric cancer cell lines were used to confirm SMPDL3B expression. RT-qPCR, Western blot, immunohistochemical, cell proliferation, assay of wound healing, transwell migration assay, invasion assay, flow cytometry, and immune evaluation experiments were carried out.

Results

SMPDL3B was found to be substantially expressed in GAC, and this condition has a bad prognosis. By establishing SMPDL3B knockdown and overexpression of GAC cell lines, this study confirmed that SMPDL3B promoted tumor cell proliferation, migration, and invasion. Additional bioinformatics research revealed a connection between SMPDL3B and immune cell infiltration in the GAC immunological microenvironment, which enhanced tumor cell proliferation by promoting the infiltration content of M2 macrophages.

Conclusion

This study determined the function of SMPDL3B for the clinical diagnosis, prediction, and novel management of GAC.

Distal Versus Total D2-Gastrectomy for Gastric Cancer: a Secondary Analysis of Surgical and Oncological Outcomes Including Quality of Life in the Multicenter Randomized LOGICA-Trial

BACKGROUND

Distal gastrectomy (DG) for gastric cancer can cause less morbidity than total gastrectomy (TG), but may compromise radicality. No prospective studies administered neoadjuvant chemotherapy, and few assessed quality of life (QoL).

METHODS

The multicenter LOGICA-trial randomized laparoscopic versus open D2-gastrectomy for resectable gastric adenocarcinoma (cT1-4aN0-3bM0) in 10 Dutch hospitals. This secondary LOGICA-analysis compared surgical and oncological outcomes after DG versus TG. DG was performed for non-proximal tumors if R0-resection was deemed achievable, TG for other tumors. Postoperative complications, mortality, hospitalization, radicality, nodal yield, 1-year survival, and EORTC-QoL-questionnaires were analyzed using Χ2-/Fisher's exact tests and regression analyses.

RESULTS

Between 2015 and 2018, 211 patients underwent DG (n = 122) or TG (n = 89), and 75% of patients underwent neoadjuvant chemotherapy. DG-patients were older, had more comorbidities, less diffuse type tumors, and lower cT-stage than TG-patients (p < 0.05). DG-patients experienced fewer overall complications (34% versus 57%; p < 0.001), also after correcting for baseline differences, lower anastomotic leakage (3% versus 19%), pneumonia (4% versus 22%), atrial fibrillation (3% versus 14%), and Clavien-Dindo grading compared to TG-patients (p < 0.05), and demonstrated shorter median hospital stay (6 versus 8 days; p < 0.001). QoL was better after DG (statistically significant and clinically relevant) in most 1-year postoperative time points. DG-patients showed 98% R0-resections, and similar 30-/90-day mortality, nodal yield (28 versus 30 nodes; p = 0.490), and 1-year survival after correcting for baseline differences (p = 0.084) compared to TG-patients.

CONCLUSIONS

If oncologically feasible, DG should be preferred over TG due to less complications, faster postoperative recovery, and better QoL while achieving equivalent oncological effectiveness. Distal D2-gastrectomy for gastric cancer resulted in less complications, shorter hospitalization, quicker recovery and better quality of life compared to total D2-gastrectomy, whereas radicality, nodal yield and survival were similar.

Diagnostic accuracy of frozen section biopsy for early gastric cancer extent during endoscopic submucosal dissection: a prospective study

BACKGROUND

Accurate diagnosis of the lateral extent of early gastric cancer during endoscopic submucosal dissection (ESD) is crucial to achieve negative resection margins. Similar to intraoperative consultation with a frozen section in surgery, rapid frozen section diagnosis with endoscopic forceps biopsy may be useful in assessing tumor margins during ESD. This study aimed to evaluate the diagnostic accuracy of frozen section biopsy.

METHODS

We prospectively enrolled 32 patients undergoing ESD for early gastric cancer. Biopsy samples for the frozen sections were randomly collected from fresh resected ESD specimens before formalin fixation. Two different pathologists independently diagnosed 130 frozen sections as "neoplasia," "negative for neoplasia," or "indefinite for neoplasia," and the frozen section diagnosis was compared with the final pathological results of the ESD specimens.

RESULTS

Among the 130 frozen sections, 35 were from cancerous areas, and 95 were from non-cancerous areas. The diagnostic accuracies of the frozen section biopsies by the two pathologists were 98.5 and 94.6%, respectively. Cohen's kappa coefficient of diagnoses by the two pathologists was 0.851 (95% confidence interval: 0.837-0.864). Incorrect diagnoses resulted from freezing artifacts, a small volume of tissue, inflammation, the presence of well-differentiated adenocarcinoma with mild nuclear atypia, and/or tissue damage during ESD.

CONCLUSIONS

Pathological diagnosis of frozen section biopsy is reliable and can be applied as a rapid frozen section diagnosis for evaluating the lateral margins of early gastric cancer during ESD.

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.

Supra-ampullary duodenectomy in a patient with positive distal resection margin after subtotal gastrectomy for gastric cancer: a case report

Resection margin involvement after curative intent resection for gastric cancer results in a poor prognosis and deprives the patient of the chance for a cure. Reoperation to achieve an R0 status should guarantee tolerable morbidity and achievement of negative margins. We performed laparoscopic distal gastrectomy with extracorporeal Billroth II reconstruction in a 56-year-old woman with gastric cancer following neoadjuvant chemotherapy. Scattered cancer cells were observed in the proximal and distal resection margins on immunohistochemical staining for cytokeratin. Two weeks postoperatively, remnant total gastrectomy and supra-ampullary duodenectomy were performed. Before reoperation, percutaneous transhepatic gallbladder drainage and angiocatheter placement outside the ampulla of Vater (AoV) via the cystic duct were performed to avoid pancreaticoduodenectomy and to obtain the maximal distal margin. Duodenal transection was performed 1 cm above the AoV. The resected duodenum was 4 cm in length. The patient had no postoperative complications and received adjuvant chemotherapy 1 month after the reoperation.

Intraoperative frozen section analysis of margin status as a quality indicator in gastric cancer surgery

INTRODUCTION

Positive pathologic margins following gastric cancer (GC) resection carries a poor prognosis. We evaluated intraoperative frozen section (IFS) analysis of resection margins (RMs) as a quality indicator in GC surgery.

METHODS

Patients referred to a provincial cancer agency with surgically resected non-metastatic GC between 2004 and 2012 were included. Associations between IFS analysis, other baseline characteristics, RMs, and overall survival (OS) were assessed using logistic regression, Kaplan-Meier analyses, and Cox proportional hazards modeling.

RESULTS

Among 377 patients, median age was 67 years, 68% were male, and 16% had +RMs. Thirty-four percent of patients underwent IFS analysis, which protected against +RMs (odds ratio [OR]: 0.34, 95% confidence interval [CI]: 0.16-0.73, p = 0.006) and improved OS (hazards ratio [HR]: 0.72, 95% CI: 0.54-0.98, p = 0.037). OS following re-resection of IFS positive patients was similar to IFS negative patients (69 vs. 54 months, p = 0.317). Stage III disease (OR: 12.8, 95% CI: 3.00-55.0, p = 0.001) and gastroesophageal junction tumors (OR: 2.25, 95% CI: 1.05-4.78, p = 0.036) predicted +RMs. Stage III disease led to worse OS (HR: 2.89, 95% CI: 1.92-4.34, p < 0.001) while intestinal histology improved OS (HR: 0.67, 95% CI: 0.50-0.90, p = 0.007).

CONCLUSIONS

IFS analysis reduce +RMs and improve OS and should be incorporated in curative intent GC surgery for patients with locally advanced GC.

Fifty years of progress in gastric cancer

As with every human malignancy, the diagnosis, staging, and treatment of patients with gastric cancer have undergone enormous evidence-based change over the last 50 years, largely as a result of increasingly rapid developments in technology and science. Some of the changes in clinical practice have derived from prospective randomized controlled trials (RCTs), whereas others have come from study of meticulously maintained prospective databases, which define the disease's natural history over time, and occasionally from in-depth analysis of a single patient with an unexpectedly good or poor outcome. Herein we summarize the more important changes in gastric cancer management and the data supporting those changes.

Minimum resection length to ensure a pathologically negative distal margin and the preservation of a larger remnant stomach in proximal gastrectomy for early upper gastric cancer

BACKGROUND

In proximal gastrectomy (PG), a longer distal margin (DM) length should be maintained to obtain a pathologically negative DM. However, a shorter DM length is preferred to preserve a large remnant stomach for favorable postoperative outcomes. Evidence regarding the minimum DM length to ensure a pathologically negative DM is useful.

METHODS

Patients who underwent PG or total gastrectomy for cT1N0M0 gastric cancer limited to the upper third were enrolled. A new parameter, ΔDM, which corresponded to the pathological extension distal to the gross tumor boundary towards the resection stump, was evaluated. The maximum ΔDM, which is the length ensuring a pathologically negative DM, was first determined. Furthermore, the possible incidences of pathologically positive DM were calculated for each pathological type and clinical tumor (cTumor) size.

RESULTS

Of 361 patients eligible for this study, 190 and 171 were assigned to differentiated (Dif) and undifferentiated types (Und), respectively. The maximum ΔDM was 30 and 40 mm in Dif and Und, respectively. Considering a correlation between cTumor size and ΔDM, and possible incidences of pathologically positive DM, 10, 20, and 30 mm were the minimal gross DM lengths in Dif when cTumor size was ≤ 15 mm, > 15 and ≤ 50 mm, and > 50 mm, respectively. In Und, the incidences of pathologically positive DM were 0.59% and 2.3% for gross DM lengths of 30 and 20 mm, respectively.

CONCLUSION

The minimum DM lengths to ensure a pathologically negative DM in PG are proposed according to the pathological type of early upper gastric cancer.

Discovery of a Redox-Activatable Chemical Probe for Detection of Cyclooxygenase-2 in Cells and Animals

Cyclooxygenase-2 (COX-2) expression is up-regulated in inflammatory tissues and many premalignant and malignant tumors. Assessment of COX-2 protein in vivo, therefore, promises to be a powerful strategy to distinguish pathologic cells from normal cells in a complex disease setting. Herein, we report the first redox-activatable COX-2 probe, fluorocoxib Q (FQ), for in vivo molecular imaging of pathogenesis. FQ inhibits COX-2 selectively in purified enzyme and cell-based assays. FQ exhibits extremely low fluorescence and displays time- and concentration-dependent fluorescence enhancement upon exposure to a redox environment. FQ enters the cells freely and binds to the COX-2 enzyme. FQ exhibits high circulation half-life and metabolic stability sufficient for target site accumulation and demonstrates COX-2-targeted uptake and retention in cancer cells and pathologic tissues. Once taken up, it undergoes redox-mediated transformation into a fluorescent compound fluorocoxib Q-H that results in high signal-to-noise contrast and differentiates pathologic tissues from non-pathologic tissues for real-time in vivo imaging.

Identification of the KCNQ1OT1/ miR-378a-3p/ RBMS1 Axis as a Novel Prognostic Biomarker Associated With Immune Cell Infiltration in Gastric Cancer

Background: Gastric cancer (GC) is the second leading cause of cancer-related mortality and the fifth most common cancer worldwide. However, the underlying mechanisms of competitive endogenous RNAs (ceRNAs) in GC are unclear. This study aimed to construct a ceRNA regulation network in correlation with prognosis and explore a prognostic model associated with GC.

Methods: In this study, 1,040 cases of GC were obtained from TCGA and GEO datasets. To identify potential prognostic signature associated with GC, Cox regression analysis and the least absolute shrinkage and selection operator (LASSO) regression were employed. The prognostic value of the signature was validated in the GEO84437 training set, GEO84437 test set, GEO15459 set, and TCGA-STAD. Based on the public databases, TargetScan and starBase, an mRNA-miRNA-lncRNA regulatory network was constructed, and hub genes were identified using the CytoHubba plugin. Furthermore, the clinical outcomes, immune cell infiltration, genetic variants, methylation, and somatic copy number alteration (sCNA) associated with the ceRNA network were derived using bioinformatics methods.

Results: A total of 234 prognostic genes were identified. GO and GSEA revealed that the biological pathways and modules related to immune response and fibroblasts were considerably enriched in GC. A nomogram was generated to provide accurate prognostic outcomes and individualized risk estimates, which were validated in the training, test dataset, and two independent validation datasets. Thereafter, an mRNA-miRNA-lncRNA regulatory network containing 4 mRNAs, 22 miRNAs, 201 lncRNAs was constructed. The KCNQ1OT1/hsa-miR-378a-3p/RBMS1 ceRNA network associated with the prognosis was obtained by hub gene analysis and correlation analysis. Importantly, we found that the KCNQ1OT1/miR-378a-3p/RBMS1 axis may play a vital role in the diagnosis and prognosis of GC patients based on Cox regression analyses. Furthermore, our findings demonstrated that mutations and sCNA of the KCNQ1OT1/miR-378a-3p/RBMS1 axis were associated with increased immune infiltration, while the abnormal upregulation of the axis was primarily a result of hypomethylation.

Conclusion: Our findings suggest that the KCNQ1OT1/miR-378a-3p/RBMS1 axis may be a potential prognostic biomarker and therapeutic target for GC. Moreover, such findings provide insights into the molecular mechanisms of GC pathogenesis.

Label-free multiphoton excitation imaging as a promising diagnostic tool for breast cancer

Histopathological diagnosis is the ultimate method of attaining the final diagnosis; however, the observation range is limited to the two‐dimensional plane, and it requires thin slicing of the tissue, which limits diagnostic information. To seek solutions for these problems, we proposed a novel imaging‐based histopathological examination. We used the multiphoton excitation microscopy (MPM) technique to establish a method for visualizing unfixed/unstained human breast tissues. Under near‐infrared ray excitation, fresh human breast tissues emitted fluorescent signals with three major peaks, which enabled visualizing the breast tissue morphology without any fixation or dye staining. Our study using human breast tissue samples from 32 patients indicated that experienced pathologists can estimate normal or cancerous lesions using only these MPM images with a kappa coefficient of 1.0. Moreover, we developed an image classification algorithm with artificial intelligence that enabled us to automatically define cancer cells in small areas with a high sensitivity of ≥0.942. Taken together, label‐free MPM imaging is a promising method for the real‐time automatic diagnosis of breast cancer.

Minimum Esophageal Resection Length to Ensure Negative Proximal Margin in Total Gastrectomy for Gastric Cancer: A Retrospective Study

Objective

To identify the minimum length of esophageal resection to ensure a pathologically negative proximal margin (PM) in total gastrectomy for gastric cancer.

Background

In total gastrectomy, a certain esophageal length is resected to obtain a pathologically negative PM because of the possibility of unexpected pathological esophageal invasion. However, a recommendation regarding the esophageal transection site in total gastrectomy has not been established.

Methods

The data of patients who underwent total gastrectomy for gastric cancer from 2005 to 2018 were collected. We evaluated the length of unexpected pathological esophageal invasion (esophageal ΔPM) in each type of disease and each location of the gross proximal tumor boundary (PB) using the length between the PB and the esophagogastric junction (PB-EGJ length).

Results

Of the 1005 patients eligible for this study, 277, 196, and 532 had cT1, cT2-4 expansive (Exp), and cT2-4 infiltrative (Inf) growth patterns, respectively. In cT1 and Exp, no unexpected pathological esophageal invasion occurred when the PB-EGJ length was >1 cm, whereas pathological esophageal invasion occurred in 20.0% of cT1 and 32.7% of Exp when the PB-EGJ length was ≤1 cm. The esophageal ΔPM was <1 cm. In Inf, no unexpected pathological esophageal invasion occurred when the PB-EGJ length was >3 cm, whereas pathological esophageal invasion occurred in 17.4% of patients when the PB-EGJ length was ≤3 cm. The esophageal ΔPM was <2 cm.

Conclusions

New recommendations regarding the esophageal resection length required to ensure a pathologically negative PM in total gastrectomy are herein proposed.

[Complete response after neoadjuvant therapy for gastric cancer: implications for surgery]

BACKGROUND

Perioperative or neoadjuvant therapy is the mainstay of treatment for locally advanced gastric cancer in Europe; however, data regarding possible modifications in the surgical strategy depending on the response to preoperative treatment are lacking.

METHODS

This review was carried out based on a search of the relevant contemporary literature regarding neoadjuvant or perioperative treatment for gastric adenocarcinoma and the implications of tumor response for the subsequent surgical treatment.

RESULTS

The most recent randomized trials showed a survival benefit after perioperative or neoadjuvant treatment for gastric cancer. Due to the variable response to the preoperatively administered part of the therapy, including complete response, it appears reasonable to develop an individualized surgical approach; however, scientific results supporting this approach are limited due to the variable quality of the surgical resection provided in these studies and the limited rate of complete response to preoperative treatment. Moreover, the reliability of clinical restaging after preoperative treatment is also limited. On the other hand, there is currently evidence that supports a re-evaluation of the necessary resection margins for partial gastrectomy in advanced gastric cancer with the help of intraoperative frozen sections and new reconstruction methods.

CONCLUSION

The current evidence does not support the implementation of a complete organ-sparing strategy with active follow-up surveillance for gastric cancer.; however, stomach-preserving partial gastrectomy techniques could be applied for advanced disease more often in the future.

Intraoperative gastroscopy to determine proximal resection margin during totally laparoscopic gastrectomy for patients with upper third gastric cancer

Background

In totally laparoscopic gastrectomy (TLG), it is usually difficult to determine the proximal margin. Therefore, the present study evaluated the usefulness of intraoperative gastroscopy for direct marking of the tumor proximal margin during TLG for cancer in the upper third of the stomach.

Methods

This retrospective cohort study included 52 patients with gastric cancer who underwent TLG from January 2018 to May 2020. The proximal margin of tumors was determined by intraoperative gastroscopic methods.

Results

Patients were divided into short (1 cm) and long (2 cm) groups according to the distance to the proximal margin of the tumor. Participants consisted of 41 males and 11 females with a median age of 63.5 years. Tumors involving the esophagogastric junction (EGJ) occurred in 27 patients. Siewert type II and III tumors were present in 42 and 10 patients, respectively. The median operative time was 244 min. The long group had a statistically significant lower frequency of positive margin than the short group (0% vs. 17.4%, P=0.033). Total gastrectomy was performed in 35 patients, and 17 patients received proximal gastrectomy. No complications associated with the procedure occurred in any patient.

Conclusions

Intraoperative endoscopic views for tumor proximal localization can be used effectively during TLG for patients with upper third gastric cancer. Our results indicate that a distance of ≥2 cm from the proximal resection margin to the tumor was necessary to achieve a negative resection margin. In the future, this may be used as an alternative to frozen section diagnosis.

Analysis of Esophagectomy Margin Practice and Survival Implications

BACKGROUND

The objective of this study was to determine how thoracic surgeons manage intraoperative esophagectomy positive margins and how these decisions may relate to overall survival and progression-free survival in esophageal cancer.

METHODS

A survey was sent to thoracic surgeons to understand the management of intraoperative positive esophagectomy margins. Primary data at two high-volume esophageal cancer institutions from 1994 to 2017 were retrospectively reviewed to identify patients who had intraoperative positive frozen section margins during esophagectomy. Patient characteristics and survival data were collected and analyzed. Overall survival and progression-free survival were assessed using a Cox model.

RESULTS

Eighty-five percent of thoracic surgeons responding to a survey reported the utilization of frozen pathologic evaluation during esophagectomy with attempts at re-resection to achieve negative margin. Our esophagectomy database identified 94 patients with intraoperative positive margins. Of those re-resected (n = 67, 63%), 44 patients (46.8%) were converted to R0 resections. overall survival was improved for patients in the R0 group (13 months) vs R+ group (3.4 months, P = .04). Progression-free survival was also improved between the R0 group (8.6 months) and the R+ group (2.2 months, P = .03). In a multivariable analysis for progression-free survival, margin status was an independent predictor of survival (hazard ratio 3.13, P = .03).

CONCLUSIONS

From a thoracic surgery survey, 85% of surgeons use intraoperative frozen section margin analysis to guide surgical decision making during an esophagectomy. Analyzing patients with a positive margin discovered during esophagectomy suggests that esophageal cancer patients who can undergo re-resection to a negative margin have increased progression-free survival. The final margin appears to be related to progression-free survival.

Peritoneal biopsy frozen section: cachexia manifesting as signet ring-like cells

Peritoneal metastases from signet ring cell adenocarcinoma may be overlooked at laparoscopy, resulting in problematic false-negative diagnoses. Conversely, false-positive diagnoses are rarely reported. For the surgeon, cachexia may rise suspicion for peritoneal metastases by exhibiting a worrisome micronodular appearance of the peritoneum, and atrophic adipocytes looks like signet ring cells at the microscopical level. Being aware of this underdiagnosed condition may help avoiding unfortunate false-positive diagnoses of peritoneal metastases during intraoperative consultation.

Prognostic Impact of Frozen Section Investigation and Extent of Proximal Safety Margin in Gastric Cancer Resection

BACKGROUND AND AIMS

Guidelines propose different extents of macroscopic proximal margin for gastric cancer and frozen margin investigation in selected cases, but data is lacking. This study was to evaluate the necessary extent of macroscopic proximal margin, accuracy of frozen margin investigation, and prognostic impact of tumor-free proximal margin length in pT2-pT4 gastric cancer.

STUDY DESIGN

Proximal and distal frozen margins were routinely investigated intraoperatively in all pT2-pT4 gastric cancers resected between 2011 and 2017. Macroscopic and microscopic proximal margin lengths were correlated. For R0-resections, survival analysis was performed for distal gastrectomy (DG) with microscopic proximal margin length ≤3 cm versus >3 cm.

RESULTS

Overall, 1484 patients were included. Microscopic proximal margin lengths were macroscopically more often misestimated in diffuse histology (P = 0.0004), but extent of underestimation in centimeter was similar to intestinal and mixed/undetermined type (P = 0.134). Fifteen cases (1.0%) resulted in R1-resection, 10 at distal, and 5 at proximal margin but none with macroscopic proximal margin ≥3 cm and negative frozen section. Overall agreement of frozen margin and final pathology was 2951/2968 (99.4%). Proximal margin length in DG did not correlate with survival or recurrence in R0-resected patients.

DISCUSSION

Diffuse histology is at higher risk for underestimation of proximal margin length, but extent of underestimation is similar in other Laurén subtypes. If ≥3 cm macroscopic proximal margin length is applied with intraoperative frozen margin confirmation, R1-resection can be avoided.

CONCLUSION

In pT2-T4a gastric cancer, proximal margin of ≥3 cm plus frozen margin confirmation provides high oncological safety. In DG patients with R0-resection, proximal margin length does not correlate with survival or recurrence.

Frozen section diagnosis of gastrointestinal poorly cohesive and signet-ring cell adenocarcinoma: useful morphologic features to avoid misdiagnosis

Frozen section examination of adenocarcinomas with poorly cohesive growth, including signet-ring cell carcinoma, is challenging. Due to their diffuse morphology, the tumor cells may be indistinct and difficult to distinguish from inflammatory or stromal cells. Misdiagnosis may result in significant adverse clinical outcome. We performed a detailed retrospective analysis of such cases to identify features that are helpful to avoid misdiagnosis at the time of frozen section. We reviewed the original frozen section slides from 50 patients with poorly cohesive carcinoma (PCC) including 32 with positive and 18 with negative frozen section slides. Tumor cells and inflammatory cells were evaluated for 17 distinct cytologic and nine architectural or stromal features. Features with 100% specificity and positive predictive value (PPV) for carcinoma included the presence of cells with a single distinct cytoplasmic mucin vacuole, focal gland formation, and perineural invasion. Features with high specificity, sensitivity, PPV, and negative predictive value (NPV) (all > 75%) included irregular nuclear contours, large nuclear size with many nuclei > 4× the size of a small lymphocyte, and disruption/obliteration of normal structures. Other features with high specificity and PPV (both ≥ 85%) but relatively low sensitivity and NPV-included crescent-shaped/indented nuclei, prominent nucleoli, anisonucleosis (> 4:1 difference in nuclear size), multinucleation, and the presence of mitotic figures. We characterized useful histologic features of poorly cohesive carcinoma that may serve to distinguish carcinoma cells from benign inflammatory or stroma cells. Knowledge of the relatively specific features in particular may help surgical pathologists avoid false-negative interpretation resulting in significant clinical morbidity.