Each type of cancer is staged differently, but stage 1 typically indicates the tumor is small or the cancer has not spread beyond its site of origin. Staging is a way of describing how severe or extensive a person's cancer is, states the National Cancer Institute.
Several systems are used to stage cancer, but the TNM system is one of the most common. Using this system, a physician assesses a cancer according to its size and extent, lymph node involvement and metastasis, according to the National Cancer Institute. T0 is used to indicate there is no evidence of a primary tumor. If a primary tumor exists, it is classified as Tis, T1, T2, T3 or T4. Tis refers to the presence of carcinoma in situ, a type of abnormal cell that may turn into cancer. Cancerous tumors are assigned a number from T1 to T4. The higher the number, the bigger the tumor or more extensive the cancer.
If the cancer has not spread to nearby lymph nodes, it is assigned a value of N0. Once the cancer spreads to nearby lymph nodes, it classified as N1, N2 or N3. The higher the number used, the greater the number of regional lymph nodes involved, reports the National Cancer Institute. Metastasis refers to the spread of cancer to other areas of the body. If the cancer has not spread beyond the site of origin or nearby lymph nodes, it is classified as M0. The cancer is assigned an M1 if it has spread to other parts of the body.