Kidney cancer is a disease that begins in the kidneys, two bean-shaped organs situated behind the abdominal organs, each about the size of a fist. The kidneys’ primary function is to filter excess water, salt, and waste products from the body, turning these substances into urine. Kidney cancer occurs when healthy cells in one or both kidneys start growing uncontrollably, forming a lump known as a tumor. The most common type of kidney cancer is renal cell carcinoma, which accounts for about 90% of cases. The exact cause of renal cell cancer is unknown; however, several risk factors have been identified. These include smoking, obesity, and high blood pressure. In the early stages, kidney cancer often does not present any symptoms and is usually detected incidentally during imaging tests for other complaints. As the tumor grows, symptoms may include blood in the urine, pain in the lower back, a lump in the lower back or side of the waist, unexplained weight loss, night sweats, fever, or fatigue. Cancer cells can grow into nearby areas and even spread to other parts of the body, a process known as metastasis.
