Methylene blue-assisted technique for harvesting lymph nodes after radical surgery for gastric cancer: a prospective randomized phase III study

Tracers in Gastric Cancer Surgery

The treatment of gastric cancer mainly depends on radical gastrectomy. Determination of appropriate surgical margins and adequate lymph node (LN) resection are two major surgical steps that directly correlate with prognosis in gastric cancer. Due to the expanding use of minimally invasive procedures, it is no longer possible to locate tumors and LNs through touch. As an alternative, tracers have begun to enter the field due to their capacities for intraoperative visualization. Herein, we summarize the application of contemporary tracers in gastric cancer surgery, including isosulfan blue, methylene blue, patent blue, indocyanine green, carbon particles, and radioactive tracers. Their mechanisms, administration methods, detection efficiency, and challenges, as well as perspectives on them, are also outlined.

Impact of retrieved lymph node count on short-term complications in patients with gastric cancer

BACKGROUND

It is well established that retrieved lymph node (RLN) counts were positively correlated with better overall survival in gastric cancer (GC). But little is known about the relationship between RLN count and short-term complications after radical surgery.

METHODS

A total of 1487 consecutive GC patients between January 2016 and December 2018 at Nanjing Drum Tower Hospital were retrospectively analyzed. Univariate analyses were performed to elucidate the association between RLN count and postoperative complications. We further identified clinical factors that might affect the RLN count.

RESULTS

Among all of the patients, postoperative complications occurred in 435 (29.3%) patients. The mean RLN count was 25.1, and 864 (58.1%) patients were diagnosed with lymph node metastasis. Univariate analyses showed no significant difference between RLN count and postoperative complications (both overall and stratified by CDC grade). Univariate and multivariate analyses further revealed that type of resection, tumor invasion, and lymph node metastasis were associated with RLN count.

CONCLUSIONS

The current study demonstrated that RLN count was not associated with postoperative short-term complications following gastrectomy of GC, which provided a rationale for the determination of a proper RLN count of curative gastrectomy.

Clinical study of harvesting lymph nodes with carbon nanoparticles in advanced gastric cancer: a prospective randomized trial

Background

The objective of this study is to evaluate the efficiency and safety of carbon nanoparticles (CNPs) for harvesting lymph nodes (LNs) in cases of advanced gastric cancer (AGC).

Methods

Patients with previously untreated resectable AGC were eligible for inclusion in this study. All patients were randomly allocated to two subgroups. In the experimental group, 1.0 mL of CNP was injected into the subserosa of the stomach around the tumor before gastrectomy with D2 dissection. The same procedure was performed directly without any coloring material in the control arm. Following surgery, LNs were harvested, colored LNs were counted, and the diameters were measured by the investigator and pathologist.

Results

Thirty patients were enrolled in the study. We observed no serious adverse effects related to CNP injection. The rate of stained LNs was 46.6 %. The mean number of harvested LNs was larger in the experimental than in the control group (38.33 vs 28.27, p = 0.041). A smaller diameter of LNs was recorded in the experimental arm (3.32 vs 4.30 mm, p = 0.023). In addition, we developed a model for predicting the total number of LNs based on the data from CNP-stained LNs and metastatic LNs (MLNs).

Conclusions

CNP is a safe material. Surgeons could harvest more LNs in patients with AGC. The harvest of an increased number of smaller diameters of LNs may be beneficial. Further study is warranted to demonstrate the model’s practicality.

Safety and performance analysis of acriflavine and methylene blue for in vivo imaging of precancerous lesions using fibered confocal fluorescence microscopy (FCFM): an experimental study

Background

Fibered confocal fluorescence microscopy (FCFM) allows in vivo investigation of pulmonary microstructures. However, the bronchial epithelium can only be imaged using exogenous fluorophores. The objective of this study is to compare methylene blue (MB) and acriflavine genotoxicity and to assess FCFM performance for in vivo imaging of precancerous lesions.

Methods

Genotoxicity was assessed using the comet assay on both cultured human lymphocytes and NCI-H460 cells, which had been exposed to MB or acriflavine before being illuminated at 660 or 488 nm, respectively. FCFM was performed on precancerous lesions in the hamster cheek pouch model, following topical application of the fluorophores. FCFM data were analyzed according to histology.

Results

No genotoxicity was found using 0.01% (w/v) MB after illumination at 660 nm for 2 and 15 min (5 mW). Acriflavine exposure (0.025%) led to DNA damages, increasing from 2 to 15 min of light exposure at 448 nm in both lymphocytes (83.4 to 88%, p = 0.021) and NCI H460 cell populations (79.9 to 84.6%, p = 0.045). In total, 11 invasive carcinoma, 24 reserve cell hyperplasia, and 17 dysplasia lesions were imaged using FCFM in vivo. With both fluorophores, the cellular density increased from hyperplasia to high-grade dysplasia (p < 0.05). With MB, the cellular diameter significantly decreased (48.9 to 13.9 μm) from hyperplasia to carcinoma (p < 0.05). In this model, a cut-off diameter of 30 μm enabled the diagnosis of high-grade lesions with a sensitivity of 94.7% and a specificity of 97%.

Conclusion

Methylene blue can be used safely to image precancerous lesions in vivo. This study does not support the use of acriflavine in humans.