renal cell carcinoma

renal cell carcinoma
Field	Oncology, Urology

renal cell carcinoma. It is the most common type of kidney cancer in adults, arising from the lining of the proximal convoluted tubule. The disease encompasses several histological subtypes, with clear cell carcinoma being the most prevalent. Management often involves a multidisciplinary approach including specialists from urology, medical oncology, and radiation oncology.

Signs and symptoms

Classic presenting symptoms, historically known as the "too late triad," include hematuria, flank pain, and a palpable abdominal mass, though this full constellation is now uncommon at diagnosis due to earlier detection. Many cases are discovered incidentally during imaging studies such as computed tomography or ultrasound performed for other reasons. Paraneoplastic syndromes are frequent and can manifest as hypercalcemia, erythrocytosis, or Stauffer syndrome, a reversible form of hepatic dysfunction. Patients may also experience constitutional symptoms like fatigue, weight loss, and night sweats.

Causes and risk factors

The strongest established risk factor is tobacco smoking, which approximately doubles the risk. Other significant factors include obesity, hypertension, and certain inherited genetic syndromes. Specific hereditary conditions predisposing to it include von Hippel-Lindau disease, Birt-Hogg-Dubé syndrome, and hereditary leiomyomatosis. Occupational exposures to agents such as trichloroethylene have also been implicated. There is a higher incidence in individuals with end-stage renal disease who develop acquired cystic kidney disease.

Pathophysiology

It is fundamentally a disease of genetic alterations, most commonly involving the VHL gene on chromosome 3p. Inactivation of this tumor suppressor gene leads to constitutive activation of the hypoxia-inducible factor pathway, promoting angiogenesis and cell growth via factors like vascular endothelial growth factor. The most common histological subtype, clear cell renal cell carcinoma, is characterized by cells with clear cytoplasm due to abundant glycogen and lipid content. Other subtypes include papillary renal cell carcinoma and chromophobe renal cell carcinoma, each with distinct genetic profiles and clinical behaviors.

Diagnosis

Diagnosis typically begins with cross-sectional imaging, with contrast-enhanced computed tomography of the abdomen and pelvis being the cornerstone for evaluation and staging. The Bosniak classification system is used to characterize complex renal cysts identified on imaging. A definitive diagnosis often requires a percutaneous biopsy, though it may be omitted prior to surgery if imaging is highly suggestive. Magnetic resonance imaging is particularly useful for evaluating tumor thrombus extension into the renal vein or inferior vena cava. Staging follows the American Joint Committee on Cancer TNM staging system.

Treatment

For localized disease, partial nephrectomy or radical nephrectomy remains the standard curative approach, with techniques including open surgery, laparoscopic surgery, and robot-assisted surgery. For patients who are not surgical candidates, ablative therapies like cryoablation or radiofrequency ablation may be considered. The treatment landscape for advanced or metastatic disease has been revolutionized by targeted therapy and immunotherapy. First-line systemic options often include tyrosine kinase inhibitors such as pazopanib or cabozantinib, and immune checkpoint inhibitors like nivolumab combined with ipilimumab. Cytokine therapy with interleukin-2 was a historical mainstay.

Prognosis

Prognosis is heavily dependent on the stage at diagnosis, with five-year survival rates exceeding 90% for localized tumors but dropping significantly for metastatic disease. The International Metastatic Renal Cell Carcinoma Database Consortium criteria and the Memorial Sloan Kettering Cancer Center prognostic models are commonly used to stratify risk in advanced cases. Factors portending a worse outcome include a high Karnofsky Performance Status, elevated lactate dehydrogenase, and hypercalcemia. Long-term surveillance is critical due to the risk of late recurrence, even decades after initial treatment.

Category:Kidney cancer Category:Urology Category:Oncology