Cancer may spread from where it began to other parts of the body.
When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they began (the primary tumor) and travel through the lymph system or blood.
- Lymph system. The cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
- Blood. The cancer gets into the blood, travels through the blood vessels, and forms a tumor (metastatic tumor) in another part of the body.
The metastatic tumor is the same type of cancer as the primary tumor. For example, if transitional cell cancer of the ureter spreads to the lung, the cancer cells in the lung are actually ureter cancer cells. The disease is metastatic cancer of the ureter, not lung cancer.
The following stages are used for transitional cell cancer of the renal pelvis and/or ureter:
Stage 0 (Papillary Carcinoma and Carcinoma in Situ)
In stage 0, abnormal cells are found in tissue lining the inside of the renal pelvis or ureter. These abnormal cells may become cancer and spread into nearby normal tissue. Stage 0 is divided into stage 0a and stage 0is, depending on the type of tumor:
- Stage 0a may look like tiny mushrooms growing from the tissue lining the inside of the renal pelvis or ureter. Stage 0a is also called noninvasive papillary carcinoma.
- Stage 0is is a flat tumor on the tissue lining the inside of the renal pelvis or ureter. Stage 0is is also called carcinoma in situ.
In stage I, cancer has formed and spread through the lining of the renal pelvis and/or ureter, into the layer of connective tissue.
In stage II, cancer has spread through the layer of connective tissue to the muscle layer of the renal pelvis and/or ureter.
In stage III, cancer has spread:
- From the renal pelvis to tissue or fat in the kidney; or
- From the ureter to fat that surrounds the ureter.