There are several types of bone cancer that people of different ages can develop. Cancer can occur in any of the tissues that make up the skeletal system, including the hard bone cells, the softer cartilage, and fibrous tissues. Some cancers are occasionally or more frequently referred to as types of bone cancer, but are actually not true bone cancer.
True or primary bone cancer is rare and refers to cancer that starts in bone tissue. There are different types of bone cancer which start in the bones, defined by the type of bone tissue that is affected. Some types of bone cancer affect children more than adults, and others affect adults more than children.
Osteosarcoma is the most common of the primary types of bone cancer. It usually develops in children and teenagers, but sometimes affects adults. Tumors occur in the bone cells and often affect areas, such as the knee, where new bone is developing as a child grows.
Chondrosarcoma is the second most common type and affects the cartilage and rarely occurs under the age of 20. These tumors are diagnosed by grade. A low grade means that it is a slow-growing tumor that is less likely to spread and more likely to be successfully treated. Non-cancerous tumors of cartilage are more common than cancerous ones.
Ewing tumor is the third most likely type of bone cancer, and is a rare tumor which usually occurs in children. Other rare types of bone cancer are malignant fibrous histiocytoma and fibrosarcoma, which are cancers of fibrous tissues that usually occur in muscles, ligaments, and other soft tissue, but occasionally occur in bone. Giant cell tumors of bone and chordomas, bone tumors in the skull or spine, are two more rare bone cancers.
Secondary bone cancer refers to situations when cancer spreads or metastases from another area of the body, such as the lungs, kidneys, or lymphatic system, to the bones. This is the most common type of cancer which affects the skeleton. It is usually not referred to as bone cancer, but rather by the name of the body part or system where the cancer started. For example, cancer of the breast tissue that has metastasized to the bones would be called metastatic breast cancer.
Other cancers technically start in the bones but are not usually referred to as bone cancer. These include leukemia, which develops in the bone marrow but is considered a blood cancer, as well as some lymphomas, such as non-Hodgkins lymphoma, that sometimes begin in marrow rather than lymph nodes. Multiple myeloma is a blood cancer that almost always occurs in bone marrow, but is still considered to be a cancer of blood rather than bone.