This study looks at cancer cachexia, which is weight, muscle, and fat loss caused by cancer. It affects patients with colorectal, lung, or pancreatic cancer that can't be removed by surgery. Cachexia can lower physical strength, quality of life, and survival rates. The study aims to identify different types of cachexia and find better treatments for it. Researchers will collect information from patients about their symptoms, physical activity, and health markers like blood tests. These findings may help create new ways to diagnose and treat cachexia, improving life for patients with advanced cancer.

• Participants will wear a device to track sleep and exercise for one week and complete surveys and tests at the start, at 3 months, and 1 year.
• Involves blood and tumor tissue sample collection, plus review of medical records and standard PET/CT scans.
• The study accepts adults (18+) with specific cancer types and plans for cancer treatment, but excludes those with planned surgeries or recent chemo for another cancer.