Bone cancer is a devastating illness in which malignant tumors replace healthy bone tissue. The primary form of this cancer begins in the bones themselves, while the secondary form involves the spread of cancer from other parts of the body to the bones. In the United States, the disease is divided into several bone cancer stages depending on the size and spread of the tumors. Stage I is the mildest form of bone cancer and may progress through more serious phases until Stage IV. While Stage IV cancer is a life-threatening condition, people can survive with proper treatment.
The American Joint Commission on Cancer (AJCC) developed the system to classify bone cancer stages in the U.S. The system uses four factors: tumor size (T), whether the cancer has spread to lymph nodes (N) or organs (M) and a grade of how aggressive the cancer is (G). Doctors will perform diagnostic tests to determine these four factors and base their treatment on how far the cancer has progressed. These tests include X-rays, biopsies and blood tests. Other countries use different staging classifications, such as the Enneking system in the United Kingdom, which only specifies three bone cancer stages.
The first three bone cancer stages in the U.S. are sometimes called localized cancer. Stage I defines bone cancer that is limited to one bone and has not spread to lymph nodes or nearby organs. The cancer must also have one of the lower grades of aggressiveness to be placed in this stage. Stage I may be subdivided based on the size of the tumor or if there are separate tumors on one bone.
The second of the bone cancer stages is similar to Stage I, except the cancer has been determined to be aggressive. Stage III is aggressive bone cancer with more than one tumor on a single bone. In these stages, the cancer still has not spread to other parts of the body.
Stage IV is significantly different from the lower cancer stages and considered much more serious. Stage IV bone cancer has spread either to surrounding lymph nodes or organs such as the lungs, brain or liver. This is also known at metastatic cancer.
Treatment for bone cancer depends on the size and location of the tumor, as well as how aggressively it is spreading. Early treatment usually involves surgery to remove the tumor and damaged tissue. Treatment for late stage or aggressive bone cancer will typically include chemotherapy and radiation therapy. It is import to pursue follow-up treatments after a bone cancer diagnosis, because the disease can reoccur in some patients.