Prognostic impact of fluorescent lymphography on gastric cancer

Indocyanine green and near-infrared fluorescence-guided surgery for gastric cancer: a narrative review

In recent years, indocyanine green (ICG) and near-infrared (NIR) fluorescence-guided surgery has become a versatile and well-researched tool for gastric cancer treatment. Our narrative review aims to explore the applications, benefits, and challenges that are associated with this technique. Initially used to detect sentinel lymph nodes in early gastric cancer, its scope has broadened to include several clinical applications. Its most notable advantages are the ability to guide standard lymphadenectomy, intraoperatively localize tumors and define tumor margins. Despite these advantages, there are still ongoing discussions regarding its accuracy, lack of standardized administration, and oncologic safety in sentinel node navigation surgery. The limited tumor specificity of ICG has been especially put into question, hindering its ability to accurately differentiate between malignant and healthy tissue. With ongoing innovations and its integration into newer endoscopic and robotic systems, ICG-NIR fluorescence imaging shows promise in becoming a standard tool in the surgical treatment of gastric cancer.

Effect of visceral obesity on outcomes of fluorescence-guided lymphadenectomy during laparoscopic gastrectomy for gastric cancer: Post hoc analysis of a randomized phase 3 trial

Objective

To explore the impact of visceral fat area (VFA) on the short- and long-term efficacy of indocyanine green (ICG)-guided D2 lymphadenectomy for gastric cancer (GC).

Methods

A post hoc analysis was performed in patients who participated in a phase 3 randomized clinical trial of ICG-guided laparoscopic radical gastrectomy vs. conventional laparoscopic radical gastrectomy from November 2018 to July 2019. The VFA was calculated based on preoperative computed tomography images. Short-term efficacy included the quality of lymph node (LN) dissection and surgical outcomes, while long-term efficacy included overall survival (OS) and recurrence-free survival (RFS).

Results

This study included 126 patients each in the ICG (high-VFA, n=43) and non-ICG groups (high-VFA, n=38). Compared with the non-ICG group, the ICG group had significantly more retrieved LNs (low-VFA: 50.1 vs. 43.9, P=0.001; high-VFA: 49.6 vs. 37.5, P<0.001) and a significantly lower LN noncompliance rate (low-VFA: 32.5% vs. 50.0%, P=0.020; high-VFA: 32.6% vs. 73.7%, P<0.001), regardless of the VFA. The ICG group had a shorter postoperative hospital stay and fewer intra-abdominal infections than the ICG group in the high-VFA patients (P=0.025 and P=0.020, respectively) but not in the low-VFA patients. Regardless of the VFA, the 3-year OS (RFS) was better in the ICG group than in the non-ICG group [low-VFA: 83.1% (76.9%) vs. 73.9% (67.0%); high-VFA: 90.7% (90.7%) vs. 73.7% (73.5%); P for interaction =0.474 (0.547)].

Conclusions

The short- and long-term efficacies of ICG tracing were not influenced by visceral obesity.

Targeting Patient-Derived Orthotopic Gastric Cancers with a Fluorescent Humanized Anti-CEA Antibody

BACKGROUND

Gastric cancer poses a major diagnostic and therapeutic challenge as surgical resection provides the only opportunity for a cure. Specific labeling of gastric cancer could distinguish resectable and nonresectable disease and facilitate an R0 resection, which could improve survival.

METHODS

Two patient-derived gastric cancer lines, KG8 and KG10, were established from surgical specimens of two patients who underwent gastrectomy for gastric adenocarcinoma. Harvested tumor fragments were implanted into the greater curvature of the stomach to establish patient-derived orthotopic xenograft (PDOX) models. M5A (humanized anti-CEA antibody) or IgG control antibodies were conjugated with the near-infrared dye IRDye800CW. Mice received 50 µg of M5A-IR800 or 50 µg of IgG-IR800 intravenously and were imaged after 72 hr. Fluorescence imaging was performed by using the LI-COR Pearl Imaging System. A tumor-to-background ratio (TBR) was calculated by dividing the mean fluorescence intensity of the tumor versus adjacent stomach tissue.

RESULTS

M5A-IR800 administration resulted in bright labeling of both KG8 and K10 tumors. In the KG8 PDOX models, the TBR for M5A-IR800 was 5.85 (SE ± 1.64) compared with IgG-IR800 at 0.70 (SE ± 0.17). The K10 PDOX models had a TBR of 3.71 (SE ± 0.73) for M5A-IR800 compared with 0.66 (SE ± 0.12) for IgG-IR800.

CONCLUSIONS

Humanized anti-CEA (M5A) antibodies conjugated to fluorescent dyes provide bright and specific labeling of gastric cancer PDOX models. This tumor-specific fluorescent antibody is a promising potential clinical tool to detect the extent of disease for the determination of resectability as well as to visualize tumor margins during gastric cancer resection.

Superior lymph node harvest by fluorescent lymphography during minimally invasive gastrectomy for gastric cancer patients with high body mass index

BACKGROUND

Fluorescent lymphography (FL) using indocyanine green (ICG) allows for the visualization of all draining lymph nodes (LNs), thereby increasing LN retrieval. However, no studies have assessed the efficacy of FL in high body mass index (BMI) gastric cancer patients, even as LN yield decreases with increasing BMI in gastrectomy. This study aimed to investigate the influence of FL on LN retrieval in high BMI gastric cancer patients.

METHODS

Gastric cancer patients who underwent laparoscopic or robotic gastrectomies from 2013 to 2021 were included. Patients were classified into two groups, with FL (FL group) or without FL (non-FL group). The effect of FL on LN retrieval was assessed by BMI. Inverse probability of treatment weighting (IPTW) was used to ensure comparability between groups.

RESULTS

Retrieved LN number decreased as BMI increased regardless of FL application (P < 0.001). According to the IPTW analysis, the mean retrieved LN number was significantly higher in the FL group (48.4 ± 18.5) than in the non-FL group (39.8 ± 16.3, P < 0.001), irrespective of BMI. The FL group exhibited a significantly higher proportion of patients with 16 or more LNs (99.5%) than the non-FL group (98.1%, P < 0.001). The FL group also had a significantly higher proportion of patients with 30 or more LNs (86.6%) than the non-FL group (72.2%, P < 0.001). In both the normal and high-BMI patients, the FL group had a significantly larger percentage of patients with a higher nodal classification than the non-FL group.

CONCLUSION

FL resulted in more LN retrieval, even in high BMI patients. FL ensures accurate staging by maintaining the appropriate retrieved LN number in high BMI gastric cancer patients.