Fatigue and Molecular Mechanisms in Cancer Patients Receiving CCRT

This study is investigating what causes fatigue in cancer patients who are receiving concurrent chemoradiation therapy (chemotherapy and radiation given at the same time). Fatigue is one of the most debilitating side effects of cancer treatment, and researchers want to understand the biological mechanisms behind it by analyzing blood and stool samples taken before, during, and after treatment. **You may be eligible if...** - You are 18 or older with any type of cancer - You are receiving at least 15 fractions (sessions) of radiation combined with chemotherapy - You have not had prior cancer treatment in the past month (except surgery or induction chemotherapy) - You can read, write, and understand English or Spanish - You are willing to provide blood and stool samples at multiple timepoints **You may NOT be eligible if...** - You have a medical condition that makes blood draws (about 50 mL over 6 weeks) unsafe Talk to your doctor to see if this trial is right for you.