Kidney cancer

Kidney cancer is usually defined as a cancer that originates in the kidney.

The two most common types of kidney cancer, reflecting their location within the kidney, are renal cell carcinoma (RCC) and urothelial cell carcinoma (UCC) of the renal pelvis.

The distinction between these two types (RCC and UCC) is important because their prognosis, staging, and management, i.e. treatment (e.g. surgery, chemotherapy etc.), are different.

Types
In addition to renal cell carcinoma and renal pelvis carcinoma, other, less common types of kidney cancer include:
 * Squamous cell carcinoma
 * Juxtaglomerular cell tumor (reninoma)
 * Angiomyolipoma
 * Renal oncocytoma
 * Bellini duct carcinoma
 * Clear-cell sarcoma of the kidney
 * Mesoblastic nephroma
 * Wilms' tumor, usually is reported in children under the age of 5.
 * Mixed epithelial stromal tumor

Rarely, some other types of cancer and potentially cancerous tumors that more usually originate elsewhere can originate in the kidneys. These include:
 * Clear cell adenocarcinoma
 * Transitional cell carcinoma
 * Inverted papilloma
 * Renal lymphoma
 * Teratoma
 * Carcinosarcoma
 * Carcinoid tumor of the renal pelvis

Cancer in the kidney may also be secondary, the result of metastasis from a primary cancer elsewhere in the body.

Location within the kidney
Kidney cancer originates in the kidney in two principal locations: the renal tubule and the renal pelvis. Most cancers in the renal tubule are renal cell carcinoma and clear cell adenocarcinoma. Most cancers in the renal pelvis are transitional cell carcinoma.

Signs and symptoms
Common signs and symptoms of a kidney cancer include, in order of prevalence: palpable mass in the abdomen, hematuria, and hydronephrosis. There may also be no signs or symptoms, however. A palpable mass is by far the most common sign. The mass typically presents first in the anterior lumbar region, between the margins of the ribs and the crista ilii; it then grows forward to the umbilicus, upwards into the hypochondrium, and downwards into the iliac and inguinal regions. In extreme cases it fills the entire belly. The colon, and sometimes a portion of the small intestines, lies in front of it. This position of the colon furnishes an important diagnostic mark of all kidney cancers.

Epidemiology
Around 208,500 new cases of kidney cancer are diagnosed in the world each year, accounting for just under 2% of all cancers. The highest rates are recorded in Northern America and the lowest rates in Asian and African regions.

In the United States in 2008, these two types together are estimated to cause 54,390 new cases and 13,010 deaths.

2005. The most recent estimates of incidence of kidney cancer suggest that there are 63,300 new cases annually in the EU25. In Europe, kidney cancer accounts for nearly 3% of all cancer cases.

In the UK kidney cancer is the eighth most common cancer in men, with 4,622 new cases diagnosed in 2005. This compares to 2,758 new cases of kidney cancer in women, giving a male:female ratio of 1.5:1. In women it is the fourteenth most common cancer. Male kidney cancer incidence rates increased by more than 85% from 7.1 per 100,000 in 1975 to 13.4 per 100,000 in 2005. In women the rates have more than doubled over the same period from 3.2 to 6.6 per 100,000. Most of the increase has occurred in older men and women, with rates more than doubling between 1975 and 2005 for men in their 70s and early 80 and women aged 65 and over. The incidence of the disease in Britain has an aspect ratio of 50.6% of the final exitus( quote by Welsh Cancer Intelligence, 2005 ).

The incidence of kidney cancer is increasing also in the United States, and this increase is thought to be real, at least in part, not due only to changes in diagnostic practices.

Some types of kidney cancer have a known hereditary or familial risk, and to date five hereditary syndromes have been associated with renal cell carcinoma.

Treatment
Treatment for kidney cancer depends on the type and stage of the disease. In Wilms' tumor, chemotherapy, radiotherapy and nephrectomy are the accepted treatments. In renal cell carcinoma, treatment depends on the stage of the cancer, but typically does not involve chemotherapy and radiotherapy, as renal cell carcinoma is resistant to these therapies. Treatment for localized renal cell carcinoma consists of nephrectomy alone, with no adjuvant (post surgical) therapy. In metastatic renal cell carcinoma,treatment consists of Targeted therapy such as torisel, nexavar and sutent, the use of immunotherapy including interferon and interleukin-2, and in some cases, nephrectomy. Other rare forms of kidney cancer, such as sarcomatoid renal carcinoma, are not disscussed here.

In children
The majority of kidney cancers reported in children are Wilms' tumors. One study of 92 children with kidney masses reported 68 Wilms' tumor, 5 congenital mesoblastic nephroma, 4 clear cell sarcoma, 4 neuroblastoma, 4 renal cell carcinoma, 2 lymphoma, 2 angiomyolipoma, 1 teratoma, 1 hemangioma, and 1 renal epithelial tumor.