What should be determined first when identifying the primary site of cancer?

Determining the primary site of cancer hinges on identifying the organ or tissue where the tumor originated. The primary site serves as the foundation for diagnosis, treatment planning, and monitoring, making it critical to establish this before exploring other factors.

When identifying the primary site, knowing the original organ or tissue provides essential context, such as potential pathways of metastasis and the most relevant treatment options. Once the primary site is established, further details about the tumor history, specific subsites, and methods of tumor removal can be clarified and scrutinized.

Subsites, while important later in the diagnosis process, depend on the location of the primary tumor. The nature of the tumor history gives insight into progression and previous treatments, and the method of tumor removal may inform the surgical approach taken, but they are secondary to understanding where the tumor began. Thus, identifying the organ or tissue of origin is the most foundational step in the cancer identification process.