Kidney cancer occurs when abnormal cells grow uncontrollably within the tissues of the kidney. The most common type in adults is renal cell carcinoma, which begins in the small filtering tubes of the kidney. Many kidney cancers are found incidentally during imaging performed for other medical reasons, while others are discovered after symptoms develop. Early diagnosis is important because treatment outcomes are generally best when the cancer is detected before it spreads.
Causes
The exact cause of kidney cancer is not always known, but several risk factors are associated with increased risk:
- Tobacco use: Smoking significantly increases the likelihood of kidney cancer
- Obesity: Excess body weight is linked to higher rates of renal cell carcinoma
- High blood pressure: Chronic hypertension may contribute to risk
- Family history: A close relative with kidney cancer may increase susceptibility
- Inherited syndromes: Such as von Hippel-Lindau disease and other genetic conditions
- Chronic kidney disease: Long-term dialysis or impaired kidney function may raise risk
- Occupational exposures: Contact with certain industrial chemicals
Symptoms
Many small kidney tumors do not cause symptoms. When symptoms occur, they may include:
- Blood in the urine (hematuria)
- Flank or back pain on one side
- A palpable abdominal or flank mass
- Unexplained weight loss
- Fatigue
- Fever not related to infection
- Loss of appetite
Diagnosis
Evaluation for kidney cancer often includes:
- CT scan or MRI: Detailed imaging to define tumor size, location, and spread
- Ultrasound: May identify kidney masses during initial evaluation
- Blood tests: Assess kidney function, anemia, and overall health
- Urinalysis: Detects blood or other abnormalities
- Biopsy: Used selectively when diagnosis is uncertain or to guide treatment decisions
- Staging studies: Additional imaging when metastatic disease is suspected
Treatment Options
Treatment depends on tumor size, stage, kidney function, and overall health:
- Partial nephrectomy: Removes the tumor while preserving healthy kidney tissue when feasible
- Radical nephrectomy: Removes the entire kidney for larger or more invasive tumors
- Robotic or laparoscopic surgery: Minimally invasive approaches used in many cases
- Thermal ablation: Cryoablation or radiofrequency ablation for select small tumors
- Active surveillance: Monitoring small masses in selected patients
- Systemic therapy: Immunotherapy or targeted therapy for advanced or metastatic disease
When to See a Specialist
Patients with blood in the urine, persistent flank pain, an abnormal kidney mass on imaging, or unexplained systemic symptoms should be evaluated promptly by a urologist. Specialized assessment can determine whether a mass is cancerous and identify the most appropriate treatment plan. Ongoing follow-up after treatment is important to monitor kidney function and check for recurrence.