Kidney cancer occurs when cells in the kidneys grow uncontrollably, forming tumors. The most common type is renal cell carcinoma, which typically starts in the lining of the kidney's tubules. Risk factors include smoking, obesity, and high blood pressure. Symptoms may include blood in the urine, persistent back pain, and unexplained weight loss. Diagnosis often involves imaging tests like CT scans or MRI, and treatment options may include surgery, radiation therapy, or targeted therapy. Early detection is crucial for improving outcomes, making regular check-ups important for those at higher risk.