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Renal cell carcinoma (RCC) is the most common renal cancer. Symptoms appear late and include hematuria, flank pain, a palpable mass, and FUO. Diagnosis is by CT or MRI and occasionally by biopsy. Treatment is with surgery for early disease and targeted therapy, an experimental protocol, or palliative therapy for advanced disease.
RCC, an adenocarcinoma, accounts for 90 to 95% of primary malignant renal tumors. Less common primary renal tumors include transitional cell carcinoma, Wilms' tumor (most often in children), and sarcoma.
In the US, about 58,000 cases of RCC and pelvic tumors and 13,000 deaths occur each year. RCC occurs slightly more often in men (male:female incidence is about 3:2). People affected are usually between 50 and 70 yr. Risk factors include the following:
RCC can trigger thrombus formation in the renal vein, which occasionally propagates into the vena cava. Tumor invasion of the vein wall is uncommon. RCC metastasizes most often to the lymph nodes, lungs, adrenal glands, liver, and bone.
Symptoms and Signs
Symptoms usually do not appear until late, when the tumor may already be large and metastatic. Gross or microscopic hematuria is the most common manifestation, followed by flank pain, FUO, and a palpable mass. Sometimes hypertension results from segmental ischemia or pedicle compression. Paraneoplastic syndromes occur in 20% of patients. Polycythemia can result from increased erythropoietin activity. However, anemia may also occur. Hypercalcemia is common and may require treatment (see Electrolyte Disorders: Treatment). Thrombocytosis, cachexia, or secondary amyloidosis may develop.
Diagnosis
Most often, a renal mass is detected incidentally during abdominal imaging (eg, CT, ultrasonography) done for other reasons. Otherwise, diagnosis is suggested by clinical findings and confirmed by abdominal CT before and after injection of a radiocontrast agent or by MRI. A renal mass that is enhanced by radiocontrast strongly suggests RCC. CT and MRI also provide information about local extension and nodal and venous involvement. MRI provides further information about extension into the renal vein and vena cava and has replaced inferior vena cavography. Ultrasonography and IVU may show a mass but provide less information about the characteristics of the mass and extent of disease than do CT or MRI. Often, nonmalignant and malignant masses can be distinguished radiographically, but sometimes surgery is needed for confirmation. Needle biopsy does not have sufficient sensitivity when findings are equivocal; it is recommended only when there is an infiltrative pattern instead of a discrete mass, when the renal mass may be a metastasis from another known cancer, or sometimes to confirm a diagnosis before chemotherapy for metastases.
Three-dimensional CT, CT angiography, or magnetic resonance angiography is used before surgery, particularly before nephron-sparing surgery, to define the nature of RCC, to more accurately determine the number of renal arteries present, and to delineate the vascular pattern. These imaging techniques have replaced aortography and selective renal artery angiography.
A chest x-ray and liver function tests are essential. If chest x-ray is abnormal, chest CT is done. If alkaline phosphatase is elevated, bone scanning is needed. Serum electrolytes, BUN, creatinine, and Ca are measured. BUN and creatinine are unaffected unless both kidneys are diseased.
Staging
Information from the evaluation makes preliminary staging possible. Robson's system is still used in the US, but the TNM (tumor, node, metastasis) system is more precise and has almost completely replaced it (see Table 1: Genitourinary Cancer: Genitourinary Cancer Staging  ). At diagnosis, RCC is localized in 45%, locally invasive in about 33%, and spread to distant organs in 25%.
Prognosis
Five-year survival rates range from 95% for the American Joint Comission on Cancer ( AJCC) stage grouping I (T1 N0 M0) to 20% for stage grouping IV (T4 with any N or M; or N2 with any T or M; or M1). Prognosis is poor for patients with metastatic or recurrent RCC because treatments are usually ineffective for cure, although they may be useful for palliation.
Treatment
Curative treatments
Radical nephrectomy (removal of kidney, adrenal gland, perirenal fat, and Gerota's fascia) is standard treatment for localized RCC and provides a reasonable chance for cure. Results with open or laparoscopic procedures are comparable. Nephron-sparing surgery (partial nephrectomy) is possible and appropriate for many patients, even in patients with a normal contralateral kidney if the tumor is < 4 cm. Nonsurgical destruction of renal tumors via freezing (cryosurgery) or thermal energy (radiofrequency ablation) is being done in highly selected patients, but long-term data about efficacy and indications are not yet available.
For tumors involving the renal vein and vena cava, surgery may be curative if no nodal or distant metastases exist.
If both kidneys are affected, partial nephrectomy of one or both kidneys is preferable to bilateral radical nephrectomy if technically feasible.
Radiation therapy is no longer combined with nephrectomy.
Palliative treatments
Palliation can include nephrectomy, tumor embolization, and possibly external beam radiation therapy. Resection of metastases offers palliation and, if limited in number, prolongs life in some patients, particularly those with a long interval between initial treatment (nephrectomy) and development of metastases. Although metastatic RCC is traditionally characterized as radioresistant, radiation therapy can be palliative when metastatic in bone.
For some patients, drug therapy reduces tumor size and prolongs life. About 10 to 20% of patients respond to interferon alfa-2b or IL-2, although the response is long-lasting in < 5%. Five new targeted therapies have shown efficacy for advanced tumors: sunitinib, sorafenib, and pazopanib (tyrosine kinase inhibitors) and temsirolimus and everolimus, which inhibit the mammalian target of rapamycin (mTOR). Other treatments are experimental. They include stem cell transplantation, other interleukins, antiangiogenesis therapy (eg, bevacizumab, thalidomide), and vaccine therapy. Traditional chemotherapeutic drugs, alone or combined, and progestins are ineffective. Cytoreductive nephrectomy before systemic therapy, or as a delayed surgical procedure to remove the primary tumor after response in the metastases, is commonly done in patients healthy enough to undergo it.
Last full review/revision December 2007 by David A. Swanson, MD
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