The Gut Microbiome and Cancer: Impact on Treatment and Outcomes

Cecilia Larocca discusses the significant role of the gut microbiome in cancer treatment and patient outcomes, focusing primarily on its influence in melanoma. She outlines how bacteria, initially thought to reside only in the gut, are also found in various tissues and are correlated with cancer development, citing examples such as H. pylori's link to gastric cancer. Larocca emphasizes that while extensive research has connected the gut microbiome to chemotherapy efficacy—particularly regarding pancreatic cancer—it lacks direct links to skin cancer so far. Importantly, the gut microbiome has been shown to impact immunotherapy outcomes, with studies indicating that a diverse microbiome alone is insufficient; the presence or absence of specific bacterial strains is more predictive. The presentation also highlights the adverse effects of antibiotics on immunotherapy responses and the varying impacts of dietary choices on cancer development and treatment efficacy. While a balanced diet, particularly adherence to the Mediterranean diet, is recommended, the efficacy of probiotics remains uncertain, with potential negative effects observed. Furthermore, fecal microbiota transplantation shows promise in overcoming resistance in immunotherapy. Larocca concludes by underscoring the need for further research and clinical trials exploring the microbiome's role in cancer therapeutics.