Are Probiotics Beneficial or Harmful for Pancreatic Cancer Outcomes?

Pancreatic cancer is influenced by interactions between cancer cells and the tumor microenvironment (TME), including tumor-infiltrating lymphocytes (TILs). Specifically, CD8 + T cells impact prognosis by eliminating cancer cells. Recent studies have revealed that microbiomes are present in pancreatic tissues and may affect tumor growth and immune responses. Additionally, recent studies revealed that the abundance of Bacteroides, Lactobacillus, and Peptoniphilus are associated with poor pancreatic cancer prognosis. This study investigates the role of oral probiotics in influencing pancreatic cancer outcomes. We retrospectively reviewed patients aged ≥ 18 years with pathologically confirmed pancreatic cancer from Seoul National University Hospital between January 2011 and January 2023. We investigated progression-free survival and overall survival between the control group and the probiotics group. Among pancreatic cancer patients undergoing palliative chemotherapy without radiotherapy and resection, there was a significant difference in overall survival (OS) when comparing the control group to the probiotics group (median: 10 months (9-11) vs. 12 months (9-19), p = 0.026). Regardless of the type of probiotics, oral probiotics may have a positive impact, but further research is still needed to understand the underlying immunological mechanisms.