Gastric cancer, one of the most prevalent malignant tumors worldwide, continues to pose significant challenges in terms of morbidity and mortality. Despite advances in medical technology, the disease remains largely undetected until its later stages, severely impacting prognosis and survival rates. Current treatment guidelines prioritize surgery as the first-line approach, supplemented by immunotherapy and targeted therapy for advanced stages. However, as traditional chemotherapy drugs reach a plateau in efficacy, new therapeutic strategies are crucial for enhancing patient outcomes.

The stability of the gut microbiota, influenced by both environmental factors and internal conditions, plays a pivotal role in digestion, metabolism, and immune responses. Recent scientific advances have highlighted the significant contribution of gut flora to health and disease. Among these, Helicobacter pylori stands out as the primary risk factor for gastric cancer development.

Helicobacter pylori infection triggers an inflammatory response and can lead to various cellular dysfunctions, including mucosal atrophy, glandular destruction, and dysplasia. These changes are the precursors to gastric cancer. Studies have revealed that the gut microbiota of gastric cancer patients exhibits notable differences compared to non-cancerous individuals.

Research has shown significant shifts in the gut flora of gastric cancer patients, characterized by an increased presence of Lactobacillus, Klebsiella pneumoniae, and Nitrospirillum, while Porphyromonas and Neisseria levels decline. These variations indicate specific bacterial functions that facilitate tumor development.

Lactic acid, produced by lactobacilli, can promote tumor growth by activating the HIF-1 pathway, serving as both an energy source for cancer cells and a catalyst for angiogenesis. Additionally, Nitrospirillum, found exclusively in gastric cancer patients but not in those with chronic gastritis, metabolizes nitrates and nitrites, a critical risk factor for gastric cancer.

In traditional Chinese medicine literature, gastric cancer is not explicitly named but is associated with symptoms such as epigastric pain, dysphagia, and nausea. The etiology is attributed to insufficient healthy qi, poor diet, emotional stress, and external environmental factors. Among these, qi deficiency is considered the primary cause, often compounded by blood stasis and toxin accumulation.

Buyang Yiwei Decoction, developed by Professor Li Ji from Heilongjiang University of Chinese Medicine, has emerged as a promising therapeutic approach. This formula contains Astragalus root, Angelica sinensis root, Chuanxiong rhizome, white paeony root, Salvia miltiorrhiza, Actinidia chinensis root, turmeric root, epimedium leaf, and Prunus mume flower. Each ingredient synergistically supports qi and blood, facilitates blood circulation, and removes stasis.

Astragalus, Angelica sinensis, and Chuanxiong, derived from the Siwu Decoction, effectively improve immune function and nutritional status after surgery. These components also positively influence gut flora, specifically enhancing Lactobacillus growth, which is crucial for maintaining a healthy gut environment.

Salvia miltiorrhiza, rich in antioxidant compounds, inhibits tumor cell proliferation and promotes apoptosis. Actinidia chinensis and turmeric root have demonstrated significant anti-inflammatory and anti-proliferative effects. Collectively, these components work to modulate the gut microbiota, alleviate chemotherapy-related side effects, and improve overall patient quality of life.

The primary active agents in Buyang Yiwei Decoction include quercetin, kaempferol, and stigmasterol, belonging to the flavonoid subclass. These compounds exhibit potent anti-cancer properties by inducing apoptosis, causing cell cycle arrest, and inhibiting tumor angiogenesis through various molecular pathways.

Research indicates that quercetin plays a critical role in inducing autophagy and apoptosis in gastric cancer cells by regulating Akt-mTOR/HIF-1α signaling. This suggests that Buyang Yiwei Decoction holds significant potential as an adjuvant therapy in conjunction with conventional chemotherapy.

The complex interplay between gastric cancer and microbiota underscores the importance of regulating gut flora in cancer management. Traditional approaches like Buyang Yiwei Decoction offer promising strategies for improving clinical outcomes and quality of life in patients with advanced gastric cancer.

While current treatments offer some relief, innovative therapies that integrate traditional knowledge with modern science are essential for addressing the global burden of gastric cancer. Continued research into the mechanisms underlying these therapeutic approaches may pave the way for more effective and patient-centered treatments in the future.