Kidney cancer occurs when cancer cells form inside the kidney’s tubules or in the kidney tissue itself. Your kidneys are fist-sized organs in your lower mid back, on each side of your spine. Kidney cancer can affect one kidney or spread to both kidneys. The survival rate for kidney cancer is high when doctors find it before it spreads to other organs. Here is a look at types of kidney cancer, kidney cancer stages, and why this information matters when it comes to kidney cancer prognosis. Types of Kidney Cancer There are several types of kidney cancer and they are classified by the type of cell and where the cancer cells formed. The most common is renal cell carcinoma (RCC). It makes up about 85 to 90% of all kidney cancer cases in the United States. The cancer cells form inside renal cortex, an area where small tubes transport urine after filtration. Renal cell carcinoma has subgroups, which include clear cell RCC, papillary RCC, and chromophobe RCC. Other rare types of kidney cancer include: Sarcoma develops in the capsule, the thin layer of connective tissue that surrounds the kidney. Transitional cell carcinoma or urothelial carcinoma begins where the urine collects before it flows down into the bladder. Wilms tumor is most common in children. There is also a rare type of kidney cancer referred to as “unclassified RCC.” This type of cancer doesn’t match any of the other categories. Stages of Kidney Cancer Once your oncologist diagnoses the type of kidney cancer you have, the next step is to determine the stage of cancer. The stage tells your oncologist if your cancer has spread and if so, how far. The stages of kidney cancer include: Stage 1 indicates the cancer is smaller than 7 centimeters (cm). This is about the size of a tennis ball and is completely contained inside the kidney. Stage 2 is a tumor larger than 7 cm, but still entirely inside one kidney. It hasn’t spread. Stage 3 means the cancer has grown beyond the kidney. It may have spread to the lymph nodes closest to the kidneys or to the tissues around the kidney, but no further. Stage 4 is the most advanced type of cancer. Stage 4 kidney cancer means it has spread to distant lymph nodes or parts of your body, such as the lungs. If you have had kidney cancer and it has returned after a course of treatment, this is recurrent cancer. You may see a combination of letters and numbers to describe staging. T is for tumor, N is for nodes (cancer spread to any lymph nodes), and M is for metastasis (cancer spread to other parts of your body). For example, someone who has stage 3 kidney cancer could see a notation such as: T1N1M0. This would mean the cancer is in one kidney and one node, but has not spread (metastasized) further. Staging Affects Treatment and Outcome Surgery is most often the first choice for treatment, especially if the cancer has not spread beyond the kidney. Surgery may involve removing part of the kidney (partial nephrectomy), the whole kidney (simple nephrectomy), or the whole kidney plus the surrounding tissue and lymph nodes (radical nephrectomy). Following surgery, if there is a chance cancer cells have spread, your oncologist may recommend chemotherapy or radiation therapy. If you can’t have surgery for any reason, your oncologist may suggest treatment with cryotherapy, radiofrequency ablation, arterial embolization, or radiation therapy. These treatments kill cancer cells and shrink the tumor. The treatment approach for advanced kidney cancer is different. Surgery to remove the kidney may still be an option. But you will likely need a different type of therapy to treat the cancer that is elsewhere in your body. Newer therapies called immunotherapy (biologic therapy) and targeted therapies may be options. Your doctor may recommend these alone or in conjunction with chemotherapy. Kidney cancer treatment is successful for many people. Earlier-stage cancers typically respond well to treatment and have a more favorable long-term outlook than later-stage cancers.