What term describes the formation and development of tumors?

The term that describes the formation and development of tumors is "oncogenesis." It specifically refers to the biological process that leads to the formation of tumors, particularly malignant tumors, through mechanisms such as genetic mutation, cellular changes, and the influence of various factors, including environmental and lifestyle choices.

While "oncology" refers to the branch of medicine dealing with the study and treatment of tumors, it does not specifically address the process of tumor formation. "Carcinogenesis" is a related term that focuses more broadly on the initiation and development of cancer, encompassing both benign and malignant tumor formation. "Pathogenesis," on the other hand, refers generally to the development of a disease and does not specifically focus on tumors. Thus, "oncogenesis" is the most accurate term in the context of the formation and development of tumors.