A Multi-omics Approach to Disclose Progression and Underlying Biology of Head and Neck Adenoid Cystic Carcinoma

The goal of this observational study is to better understand why some people with metastatic adenoid cystic carcinoma (ACC) of the head and neck have slow-growing disease while others have faster-growing or more aggressive disease. Researchers want to learn how the biology of the tumor relates to each person's clinical risk group, which is based on a published prediction tool (a nomogram). The main question the study aims to answer is: Do people in the high-risk and low-risk groups have different biological tumor types (called ACC-I and ACC-II) when their primary tumor is tested? The study will also look at other important questions, such as: * Do metastatic tumors show the same biological type as the original tumor? * Do biological types differ based on where metastases grow or how early or late they appear? * Are biological types linked to how well systemic treatments work? * Can bl