Bone cancer diagnosis begins with a thorough medical history and physical examination, focusing on the location and characteristics of pain or other symptoms. Imaging tests, such as X-rays, CT scans, and MRI scans, are crucial for visualizing the tumor and assessing its size and extent. A bone biopsy, involving the removal of a small tissue sample from the suspected cancerous area, is necessary for definitive diagnosis. The biopsy sample is then examined under a microscope (pathology) to confirm the presence of cancer cells and determine the specific type and grade of the cancer. Further blood tests may also be used to evaluate overall health and detect markers associated with certain bone cancers.

Diagnosing bone cancer involves a combination of methods, beginning with a thorough medical history and physical examination. The doctor will ask about symptoms, family history of cancer, and any potential risk factors. Then, several diagnostic tests may be used:

• X-rays: These are often the first imaging test used. They can reveal abnormalities in bone structure, like tumors or fractures.
• Computed tomography (CT) scans: These provide more detailed images than X-rays, creating cross-sectional views of the bone. They can help determine the size and extent of the tumor.
• Magnetic resonance imaging (MRI) scans: MRIs are excellent for visualizing soft tissues and can better delineate the tumor's boundaries and its relationship to surrounding structures, including nerves and blood vessels.
• Bone scans: These scans use a radioactive tracer to detect areas of increased bone metabolism, which can indicate the presence of a tumor. While helpful in detecting spread, they aren't as precise as CT or MRI in pinpointing tumor location.
• Biopsy: This is the definitive diagnostic test. A small sample of bone tissue is removed and examined under a microscope by a pathologist. The biopsy can determine the type of cancer (e.g., osteosarcoma, Ewing sarcoma) and its grade (aggressiveness). There are several types of biopsies: needle biopsy (less invasive), incisional biopsy (removing a portion of the tumor), and excisional biopsy (removing the entire tumor, sometimes serving as a treatment as well).
• Blood tests: While not directly diagnosing bone cancer, blood tests can check for elevated levels of certain substances, such as alkaline phosphatase, which may indicate bone damage or tumor activity. They may also check for markers associated with specific types of bone cancer.

The combination of these tests allows doctors to confirm the diagnosis, determine the type and stage of the cancer, and plan appropriate treatment. The specific tests used will depend on the individual's symptoms, the location and suspected nature of the tumor, and other factors.