Kidney cancer is cancer that begins in the kidneys, a pair of fist-sized organs that remove waste and excess fluid from the blood and produce urine. The kidneys also produce hormones that help regulate blood pressure and prompt the production of red blood cells.
The most common type of kidney cancer is renal cell carcinoma (RCC). This type accounts for an estimated 9 out of 10 cases of kidney cancer. It is also known as renal cell cancer and renal cell adenocarcinoma. Because so many cases of kidney cancer are RCC, people sometimes use renal cell carcinoma synonymously with kidney cancer.
There are several different subtypes of RCC. Subtypes are categorized based on how the cancer cells look when examined under a microscope. To determine the subtype, a healthcare team will order a biopsy, where a sample of the cancerous cells are removed and then sent to a lab for testing.
Knowing the subtype of RCC can be helpful when determining how the cancer is behaving in the body and the best approach to treatment.
Clear cell renal cell carcinoma (ccRCC)
The most common type of RCC is called clear cell renal cell carcinoma. This type accounts for approximately 70 to 80 percent of cases of RCC. As the name implies, the cancerous cells appear clear (or very pale) when examined under a microscope.
Papillary renal cell carcinoma (PRCC)
Renal cell carcinoma cells that do not appear clear or very pale under a microscope can be referred to as non-clear renal cell carcinomas. These are much less common, and several different subtypes fall under this category.
The most common subtype in this category is papillary renal cell carcinoma. It accounts for approximately 10 to 15 percent of cases of RCC (making it the second-most common subtype overall). Its name comes from finger-like formations called papillae which form throughout the tumor. It can be categorized as Type 1 or Type 2. Type 1 is slow-growing and Type 2 is more aggressive and grows more quickly.
Treatment for PRCC is very much a case-by-case scenario, and patients are advised to work with a healthcare provider that specializes in treating this type of cancer.
Chromophobe renal cell carcinoma
This type is the third most common, and accounts for roughly 5 percent of cases of RCC. Under a microscope, the cells appear pale. The cells are pale in color like ccRCC cells, but have important molecular differences—they mutate differently, originate in different locations in the kidneys, and produce energy differently.
Other types
While the three cancers described above are the three most common types of RCC, there are other types that are rare. These include collecting duct RCC and medullary RCC which account for 1 percent of cases each, as well as clear cell papillary RCC, which has features of both papillary and clear subtypes and accounts for 2 to 4 percent of cases.
RCC can also be labeled “unclassified” because the cancer cells do not meet the criteria of other types or more than one type of cancer cell is present. Approximately 2 to 3 percent of cases are unclassified. There are also other types of kidney cancer that are not RCC.
Individualized treatment
It is important to remember that every case of kidney cancer is different and that treatment for kidney cancer is individualized. This means that a healthcare team will take into consideration many factors about the cancer and about the person with cancer when determining the best approach to treatment—and your healthcare team is always your best source of information about your diagnosis.
Surgery may be the preferred treatment for early stages of ccRCC. More advanced cases may be treated with immunotherapy or targeted therapy medications. Radiation therapy and chemotherapy may be used in some cases. Therapies that destroy cancer cells by freezing (cryoablation), high-frequency radio waves (radiofrequency ablation), or by stopping blood supply to the kidney (embolization) may also be used.
