Optimal Extent of Transhiatal Gastrectomy and Lymphadenectomy for the Stomach-Predominant Adenocarcinoma of Esophagogastric Junction: Retrospective Single-Institution Study in China

Siewert II esophagogastric junction adenocarcinoma: Still searching for the right treatment transabdominal or transthoracic surgical approaches?

INTRODUCTION

To date, the discussion is still ongoing whether the Siewert II adenocarcinoma of the esophagogastric junction (AEG) should be resected either by thoracoabdominal esophagectomy or gastrectomy with resection of the distal esophagus by transhiatal extension. The aim of our study was to compare the oncological and perioperative outcomes of the transthoracic approach (TTA) and the transabdominal approach (TAA).

METHODS

Searches of electronic databases identifying studies from Cochrane, PubMed and Google Scholar were performed. Randomised and non-randomised studies comparing TTA and TAA approaches for surgical treatment of AEG Siewert type II were included. The Newcastle-Ottawa and Jada scales were used to evaluate methodological quality. The risk of bias was assessed using the Rob v2 and Robins-I tools. Meta-analyses were conducted for the outcomes.

RESULTS

We included 17 trials (2 randomised controlled trials and 15 cohorts) involving 15297 patients. Longer three-year overall survival, five-year overall survival and R0 resection rates were observed in the TTA group. However, TTA had greater morbidity and pulmonary complications.

CONCLUSION

Transthoracic approach appears to be preferable for selected Siewert II tumours. This may lead to higher survival rates and better R0 resection rate. Well-designed studies are needed to confirm the results of this systematic review.

Total laparoscopic versus laparoscopic-assisted transabdominal posterior mediastinal digestive tract reconstruction in the treatment of Siewert II adenocarcinoma of the esophagogastric junction: A retrospective study

Background

The method of operation and the range of resection for Siewert II adenocarcinoma of the esophagogastric junction (AEG) remain controversial. This study aims to evaluate the safety, feasibility, and short-term postoperative effect of total laparoscopic versus laparoscopic-assisted transabdominal posterior mediastinal digestive tract reconstruction in the treatment of Siewert II AEG.

Methods

Total laparoscopic or laparoscopic-assisted gastrointestinal reconstruction through abdominal posterior mediastinum was performed in 108 patients with Siewert II AEG from October 2017 to February 2019. This study evaluated the loss of intraoperative blood, the number of lymph nodes, the marginal of the tumor, short-term postoperative complications (within 30 days), the rate of survival at follow-up, and the economic cost, feasibility, and effect of short-term postoperative recovery for patients who received these two operations.

Result

There were no significant differences in general data between the total laparoscopic group and the laparoscopic-assisted group (P > 0.05). However, the total laparoscopic group cost more time on the surgical procedure and digestive tract reconstruction, lost less intraoperative blood, and had more mediastinal lymph nodes compared with the laparoscopic-assisted group (P < 0.05). The total laparoscopic group was significantly better than the laparoscopic-assisted group compared with the short-term postoperative recovery indexes, such as the first exhaust time, the first defecation time, the first fluid time, the first semi-fluid diet time, the postoperative hospital stay, and other postoperative recovery indexes (P < 0.05). In addition, there were no significant differences in postoperative complications, postoperative pathological indexes, the recurrence rate, and mortality between the total laparoscopic group and laparoscopic-assisted group (P > 0.05).

Conclusions

The safety, feasibility, and short-term effect of total laparoscopic transabdominal posterior mediastinal digestive tract reconstruction in the treatment of Siewert II AEG were better than those for the laparoscopic-assisted group.

Targeting of the tumor immune microenvironment by metformin

Stimulating antitumor immunity is an attractive idea for suppressing tumors. CD4 + and CD8 + T cells as well as natural killer cells (NK) are the primary antitumor immune cells in the tumor microenvironment (TME). In contrast to these cells, regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), cancer-associated fibroblasts (CAFs), and tumor-associated macrophages (TAMs) release several molecules to suppress antitumor immunity and stimulate cancer cell invasion and proliferation. Adjuvant treatment with certain nontoxic agents is interesting to boost antitumor immunity. Metformin, which is known as an antidiabetes drug, can modulate both antitumor and protumor immune cells within TME. It has the ability to induce the proliferation of CD8 + T lymphocytes and NK cells. On the other hand, metformin attenuates polarization toward TAMs, CAFs, and Tregs. Metformin also may stimulate the antitumor activity of immune system cells, while it interrupts the positive cross-talk and interactions between immunosuppressive cells and cancer cells. The purpose of this review is to explain the basic mechanisms for the interactions and communications between immunosuppressive, anti-tumoral, and cancer cells within TME. Next, we discuss the modulating effects of metformin on various cells and secretions in TME.