Diagnosing Bone Cancer
5) PET (Positron Emission Tomography): A positron emission tomography (PET) scan is a process where a small amount of radioactive glucose (sugar) is injected into a vein and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body.
6) Laboratory Test
Blood tests to determine the level of an enzyme called alkaline phosphatase. When cancer spreads to the bones, certain substances that can be found by routine lab tests might be released into the blood. For example:
Calcium: Bone metastases can dissolve the bones, leading to a high blood calcium level (called hypercalcemia). Problems other than bone metastases can cause high calcium levels, but if a person with cancer has a high blood calcium level, tests are often done to look for bone metastases.
Alkaline phosphatase: When the bones dissolve, the levels of alkaline phosphatase or ALP may increase. Alkaline phosphatase is also made by the liver, so high ALP levels can mean liver problems. (They don’t always mean bone metastases.)
Several substances can be released into urine when bone is damaged. One substance that can be measured is called N-telopeptide.
Once physical examination, imaging and laboratory tests results suggest bone metastasis, this makes the diagnosis positive to have cancer. But if all of these are not certain, doctor will conduct a biopsy.
In most cases, cancer is diagnosed by removing a small piece of body tissue and looking at it under a microscope. This procedure is called a biopsy.
During a biopsy, tissues or cells are removed from the body so they can be tested in a laboratory. The pathology report from the laboratory will confirm whether or not cancer cells are present in the sample.
CT scans used to guide a biopsy needle into a suspected area of bone metastasis deep in the body. The doctor guides the needle during CT scan through the skin to the suspected unusual area. This process is repeated until the needle reach there. A tiny piece of tissue is then taken out and checked in the lab to see if there are cancer cells in it.
Two types of biopsy is done
• Needle Biopsy: The surgeon makes a small hole in the bone and removes a sample of tissue from the tumour with a needle-like instrument.
• An Incisional Biopsy. The surgeon cuts into the tumour and removes a sample of tissue.
8) Cell and Tissue Studies
Cell and tissue studies look closely at the cells of the tumour for specific information about the type of bone cancer. Cells can be gathered from tissue removed during a biopsy or surgery.
Cell and tissue studies are often done to see what the cells look like, which helps doctors identify the type of tumour. Sometimes specific chromosomal abnormalities can also be identified.
9) Blood Chemistry Tests
Blood chemistry tests measure certain chemicals in the blood. They show how well certain organs are functioning and can also be used to detect abnormalities. Occasionally, blood chemistry tests may be used to diagnose or stage bone cancer. However, blood test results are usually not helpful in detecting sarcoma.
With osteosarcoma, serum alkaline phosphatase is higher than normal in 45%–50% of people. With Ewing sarcoma, lactate dehydrogenase (LDH) may be increased when the tumour is large or the cancer has spread (metastatic disease).