Kidney Cancer

Kidney cancer refers to a malignant tumor that develops in the kidney. Depending on where it originates, kidney cancer is classified as renal cell carcinoma (RCC) or urothelial carcinoma of the renal pelvis. In clinical practice, the term “kidney cancer” usually refers to renal cell carcinoma, which accounts for about 80–90% of all primary kidney cancers. The remaining cases include benign tumors and rare sarcomas.

Kidney cancer often develops silently, without symptoms in the early stages. Most tumors are discovered incidentally during imaging tests such as ultrasound or CT scans. When symptoms occur, they usually appear once the tumor has grown large or has spread to other organs.

Classic symptoms (appear in advanced stages):

• Flank pain
• Hematuria (blood in the urine)
• A palpable mass in the flank or upper abdomen

These three signs occur together in only 10–15% of patients, and their presence usually indicates advanced disease.

Other possible symptoms:

• Unexplained weight loss
• Fatigue
• Loss of appetite
• Fever
• Symptoms of metastasis (e.g., lung involvement, neurological symptoms from brain metastases)

The causes of kidney cancer involve environmental, genetic, and medical factors.

• Lifestyle factors: Smoking, obesity, hypertension, and certain dietary habits are linked to increased risk.
• Genetics: A family history of RCC increases the risk by 4–5 times. Several hereditary syndromes are associated with higher risk.
• Pre-existing kidney disease: Patients with chronic kidney failure or long-term dialysis are at increased risk.

Although not all kidney cancers can be prevented, the following measures may lower risk:

• Quit smoking: Smokers are 1.5–2.5 times more likely to develop kidney cancer.
• Balanced diet and regular exercise: Eat fresh fruits and vegetables, avoid high-fat animal products, and maintain a healthy weight.
• Regular check-ups: Since early kidney cancer often causes no symptoms, periodic abdominal ultrasound can be considered for those with family history or genetic risk.
• Control blood pressure: About 18% of kidney cancers are linked to hypertension.
• Limit exposure to harmful chemicals: Reduce occupational exposure to pesticides, solvents, radiation, or heavy metals, and use appropriate protective equipment.