How is cancer referred to based on its origin?

Cancer is referred to by the organ where it originally formed because this designation provides critical information about the type of cancer and its characteristics. For example, if cancer originates in the lungs, it is classified as lung cancer, regardless of whether it has spread elsewhere in the body. This classification helps in understanding the cancer's behavior, devising a treatment plan, and predicting outcomes.

The other options do not hold as much relevance when identifying cancers. Metastasis locations are important for staging and treatment but do not define the cancer type itself. The type of treatment used is not a defining characteristic of the cancer; rather, it is a response based on the cancer's nature and extent. Symptoms also vary widely among different cancers and do not serve as a basis for naming them. Therefore, categorizing cancer by its original site allows for more targeted and effective healthcare strategies.