How Abdominal Chemotherapy May Help the Immune System Fight Stomach Cancer
- 6 hours ago
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Matsumiya, M., Sonoda, H., Yamashita, H. et al. Intraperitoneal Paclitaxel-Induced Eosinophil Recruitment as a Potential Mediator of Tumor Response in Peritoneal Metastases from Gastric Cancer. Ann Surg Oncol (2026). https://doi.org/10.1245/s10434-025-19075-x
What was studied?
Researchers looked at how intraperitoneal chemotherapy (medicine delivered directly into the abdominal cavity) affects the immune environment in people with gastric (stomach) cancer that has spread to the peritoneum (lining of the abdomen). Specifically, they studied paclitaxel, a chemotherapy drug, and how it might recruit certain immune cells called eosinophils, which could help fight cancer cells.
Why is this important?
When cancer spreads to the peritoneal surface, it’s often hard to treat because standard systemic (whole-body) chemotherapy may not reach the tumor effectively. Delivering chemotherapy directly into the abdomen allows higher drug levels right where the cancer is.
Key Findings
1. Chemotherapy changed immune cells in the abdomen: After intraperitoneal paclitaxel, the types of immune cells found in the abdominal fluid shifted. There were fewer helper T cells and more myeloid cells — a group that includes eosinophils.
2. Eosinophils increased after treatment: In many patients, especially those who responded well to treatment, there was a notable rise in eosinophils — white blood cells usually linked to allergic reactions but also capable of killing cancer cells.
3. Higher eosinophils were linked with better outcomes: Patients with more eosinophils after treatment were more likely to have:
Cancer cells no longer detected in abdominal fluid
Eligibility for additional surgery
Better overall survival compared to patients with fewer eosinophils
4. Eosinophils showed cancer-killing behavior: Lab tests suggested that the eosinophils activated by paclitaxel could directly induce cancer cell death.
What does this mean for patients?
Intraperitoneal chemotherapy with paclitaxel may not only kill cancer directly but also stimulate your immune system in a helpful way.
Eosinophils in the abdominal cavity might serve as a marker of good response to treatment.
In the future, measuring eosinophils could help doctors predict who will benefit most from this approach, and strategies that enhance eosinophil recruitment might improve outcomes.
Bottom Line
Delivering chemotherapy directly into the abdomen changes the immune environment in some patients with gastric cancer that has spread inside the belly. A rise in specific immune cells (eosinophils) after treatment may be linked with better response and survival, offering insights for future therapies and monitoring.
