How early can bone cancer be diagnosed? What are early symptoms?

Vary with type of ca. Some bone cancers cause pain and swelling, others may be silent in the early stages. There are too many different types of bone cancers to provide one answer to the question.
Not 1 disease. Bone cancer is not just 1 disease. Most bone cancers arise from another site in the body. Bone marrow cancers are different. Bone cancers usually present with pain. Bone marrow cancers can present in many ways, and are frequently associated with blood test abnormalities. Does this answer your question?
By early visit. During routine visit to the doctor after examination may order an x ray based on complaint of slight pain or minimum swelling.

Related Questions

What are the early symptoms that might be from bone cancer?

Pain. It depends a lot on whether the tumor started in the bone, or spred there from another source. Best way to evaluate is to see your physician, and get a few tests, mainly xrays. Read more...