Blood in the urine - 59% - Subtypes

Renal cell carcinoma symptoms

Symptom	Patients
Blood in the urine	59%
Abdominal mass	45%
Back or flank pain	41%
Weight loss	28%
Low blood counts (anemia)	21%
Tumor calcification on x-ray	13%
Symptoms of metastases	10%
Fever	9%
High calcium in blood	7%
High blood counts	7%

Subtypes of Renal Cell Carcinoma (RCC)

Not all kidney cancers are the same. There is an increasing understanding among clinicians and researchers that there are different subtypes of RCC and that they behave quite differently, both with regard to how aggressive they are in the patient and how they respond to treatment. Ten or fifteen years ago, it was common for a pathology report from a patient with kidney cancer to read simply “Renal Cell Carcinoma.” This simple diagnosis is now thought to be incomplete. Identification of the specific subtype or cell type (histology) of the kidney cancer can be as important in determining patient prognosis as knowing the stage or grade of the RCC. Your doctor should give you information regarding the histology, grade and stage of your kidney cancer. If not, you should feel comfortable asking for this information since it is an important part of your treatment planning.

The subtypes of RCC come from the description of the cell’s appearance and other characteristics. They include:

• Clear Cell (conventional) RCC: This is the most common form of kidney cancer and represents between 66% and 75% of all cases. Clear cell RCC is the cell type associated with the von Hippel Lindau (VHL) gene mutation in hereditary kidney cancer. In fact, approximately 70% of non-hereditary cases of clear cell RCC also have aVHL mutation. Much of today’s research, which is attempting to identify new effective treatments for patients with locally advanced or metastatic disease, is focused on this disease subtype since it is the most common type of RCC. When the tumor has not spread, prognosis is very good following surgical excision. Prognosis for the patient is directly related to both the cancer’s stage (tumor size and rate of growth) and grade (the characteristics of a tumor’s cell structure). Staging and grading are both explained later in this chapter. Patients with metastatic clear cell RCC – or a tumor that has spread to other parts of the body – have a significantly poorer prognosis.
• Papillary RCC: This is the second most common form of kidney cancer, making up approximately 15% of cases. Papillary RCC itself is divided into two subtypes based on cell appearance: Type I (5%) and Type II (10%). There is an increased incidence of papillary RCC in African Americans and an increased incidence of bilateral disease (involving both kidneys) associated with this subtype. There are also hereditary forms of both Type I and Type II papillary RCC. When papillary RCC has not spread, surgical removal is usually associated with an excellent prognosis. However, when papillary RCC metastasizes to other locations in the body, most conventional therapies for RCC, such as immunotherapy are ineffective.
• Chromophobe RCC: This rare form of kidney cancer represents approximately 5% of RCC cases. This type of RCC is thought to originate from the same cell type as those that form renal oncocytomas (see below). Hybrid tumors that contain features of both chromophobe RCC and renal oncocytoma have also been diagnosed. There is a familial or inherited form of chromophobe RCC (in association with renal oncocytoma) called Birt Hogg Dubé syndrome, which is also associated with a specific genetic mutation. Chromophobe RCC rarely metastasizes until very late in its clinical course, and surgical removal of localized or even locally advanced disease is usually associated with an excellent prognosis. Metastatic chromophobe RCC is quite rare, and no standard therapy currently exists.
• Renal Oncocytoma: This is a benign tumor of the kidney that makes up approximately 5% of all kidney tumors. These tumors do not metastasize, although they can grow to a large size in the kidney and invade local structures, which can result in symptoms requiring surgery. They are thought to be related to chromophobe RCC, and it can be quite difficult to differentiate the two. The tumor is treated by a partial or complete removal of the kidney.
• Unclassified RCC: Less than 1% of renal cell carcinomas are an unclassified type and are very rare. They don’t fit into one of the more common subtypes of RCC listed above. When examined under a microscope, these unclassified cancer cells have a structure and genetic features that don’t match the description of the more common RCC subtypes. This category usually includes aggressive tumors that do not respond to traditional therapy for RCC.
• Collecting Duct Carcinoma: This is a rare and very aggressive variant of kidney cancer that represents less than 1% of cases. This form of RCC is usually metastatic at the time of diagnosis, and is more common in younger individuals. Treatment has been directed at using chemotherapy-based regimens, similar to those used in the treatment of transitional cell carcinoma (see below), as these tumors do not respond to traditional RCC therapies such as bioimmunotherapy.
• Medullary RCC: This is also a very rare and aggressive variant of kidney cancer, thought to be a variant of collecting duct carcinoma. It is commonly associated with the sickle cell trait, and therefore is more common in the African-American population. It represents less than one percent of all kidney cancers diagnosed. Chemotherapy remains the main focus of treatment for this disease.
• Sarcomatoid RCC: This condition, known as “differentiation,” can occur with any of the common RCC subtypes. The term refers to the fact that the RCC cells -- when viewed under the microscope -- have the appearance of sarcoma cells. The percentage of sarcomatoid differentiation is usually reflected in the tumor’s pathology report and relates to the tumor’s aggressiveness. The prognosis associated with Sarcomatoid RCC is usually poor. The condition is found frequently in patients whose kidney cancer has metastasized widely. This form of kidney cancer is sometimes treated with chemotherapy.
• Transitional Cell Carcinoma of the Kidney: Transitional cell carcinoma (TCC) of the kidney is a rare and potentially very aggressive tumor that should not be considered a true kidney cancer, but instead should be grouped with those cancers that develop from cells that line the urinary tract. This includes TCC of the urinary bladder, which is far more common than TCC of the kidney. If the cancer has not spread, the tumor can be treated by surgical removal of both the kidney and its ureter, although recurrences of TCC in the bladder are common.