The stages of bone cancer are stage 1, stage 2, stage 3 and stage 4, according to the American Cancer Society. These stages are further broken down into the size of the tumor and whether it has spread outside of the bone, and whether it is considered low or high grade.
There are two kinds of stage 1 bone cancer, according to the American Cancer Society. In stage 1A, the tumor is less than 3 inches in diameter, has not spread to nearby lymph nodes or anywhere else in the body, and is low grade. In stage 1B, the tumor is larger than 3 inches in diameter, still has not metastasized, and is still low grade.
Stage 2A and 2B are similar to stages 1A and 1B except the tumor is considered high grade, according to the American Cancer Society. In stage 3, the tumor still has not spread to distant sites, but is found in more than one place on the same bone. The tumors are high grade. In stage 4, the tumors have metastasized to sites outside the bone. They can be any size and any grade. In 4A, the cancer has invaded the lung. In 4B, the cancer has spread to distant sites in addition to the lung, or to the nearby lymph nodes.