What term describes the widespread metastasis of cancer?

The term that accurately describes the widespread metastasis of cancer is "carcinomatosis." This term is used specifically when referring to a condition where cancer cells are present throughout the body, often indicating that the cancer has spread extensively from its original site. Carcinomatosis is commonly associated with certain types of cancers that tend to disseminate widely, leading to multiple tumor sites and affecting various organs.

In contrast, "metastasis" refers to the process by which cancer cells spread from the original tumor to other parts of the body, but it does not inherently imply that this spread is extensive or widespread. "Oncogenesis" describes the process of tumor formation and the development of cancer, rather than its spread. "Adenocarcinoma" is a specific type of cancer that arises from epithelial tissue and produces glandular structures, which does not directly pertain to the concept of widespread metastasis. Thus, "carcinomatosis" is the most appropriate term for describing the extensive spread of cancer throughout the body.