This study looks at how a plant-based diet affects people with pancreatic ductal adenocarcinoma (**PDAC**), a type of pancreatic cancer. It focuses on how diet and gut microbiome (the bacteria living in your stomach) impact the success of chemotherapy given before surgery, called **neoadjuvant therapy**. The study is observational, meaning you only complete surveys and provide a fecal sample; no experimental treatment is given. The study aims to see if the variety of gut bacteria or a healthy diet, measured by the **HEI-2015** dietary score, can predict a better response to treatment.

Key Points:

• Participants must be 18 or older and diagnosed with resectable PDAC.
• The study requires a dietary survey and a sample of feces.
• Excludes those with advanced PDAC or who have had chemotherapy.