Renal cell carcinoma represents the most commonly diagnosed kidney cancer today. RCC begins as a small growth of cancerous cells in the tissues that line the small tubules of the kidney and progresses to form well-defined masses. Because the disease does not elicit symptoms in its earlier stages, many patients remain undiagnosed until the cancer has advanced. As the disease progresses, patients often develop severe imbalances in electrolytes -- namely calcium levels, which tend to skyrocket.
Common Complications
Those suffering from RCC are often unaware of their condition until the cancer has progressed. Patients typically present with abdominal, back or flank pain; blood in the urine; enlarged or swollen abdomen; and/or a palpable mass. Other symptoms include unintentional weight loss, fever and night sweats. Depending on the stage of the cancer, kidney dysfunction is likely and progresses rapidly, leading to severe imbalances in the body’s electrolytes.
Electrolyte Imbalances
Patients with more advanced RCC often experience an excess in blood-borne calcium, also known as hypercalcemia. This is thought to occur because the tumors secrete a protein that mimics parathyroid hormone, which encourages calcium release from the bone. Severe hypercalcemia is often correlated with cancer that has metastasized, breaking down the bone’s matrix and releasing calcium into the blood.
Sodium levels are not typically affected in the normal course of RCC; however, an article in the 2008 issue of "Clinical Cancer Research" indicates that patients with serum sodium levels near the higher end of the normal range exhibit a more positive prognosis and experience improved outcomes.
Potassium levels in RCC patients can sometimes fall below the norm -- a condition known as hypokalemia. Because of the typical tumor location, potassium reabsorption is impaired, and crucial amounts of the mineral are wasted due to increased urination resulting from hypercalcemia.
In a typical nonmetastatic case, removal of the tumor by nephrectomy is likely to resolve the imbalance in electrolytes; however, electrolyte problems in cases in which the cancer has spread to the lungs, lymph nodes and/or bone may be more difficult to correct.
Dietary Considerations
If you suffer from RCC and suspect or have confirmed an electrolyte imbalance, it is important to alter your diet to accommodate positive changes in your condition. In general, foods high in sodium, such as processed or packaged meat and cheese, should be avoided because of their effect on blood pressure and fluid retention. Instead, eat fresh, organic foods without preservatives. Consume foods high in potassium, such as bananas, greens, strawberries and whole grains.
When to Call Your Doctor
Electrolyte imbalances resulting from renal cell carcinoma exhibit a variety of symptoms. Although these can often be indicative of other medical conditions, call your physician if you experience persistent or intermittent nausea and vomiting, loss of appetite, significant unintentional weight loss, muscle weakness, fatigue, confusion, joint and muscle pain, frequent urination, or heart palpitations.
References
- “Clinical Cancer Research”; Prognostic Factors in Renal Cell Carcinoma: Association of Preoperative Sodium Concentration With Survival; Vasudev, N.S. et. al; 2008
- “Human Pathology”; Hypercalcemia Associated With Renal Cell Carcinoma: Probable Role of Neoplastic Stromal Cells; Fan and Smith, D.J.; 1983
- “Reviews in Urology”; Paraneoplastic Syndromes in Urologic Malignancy: The Many Faces of Renal Cell Carcinoma; Palapattu, G.S. et al.; 2002
- “The Journal of Urology”; Hypercalcemia in Patients With Metastatic Renal Cell Carcinoma: Effect of Nephrectomy and Metabolic Evaluation; Walther, M. et al.; 1997
- Cornell University: Kidney Cancer
- MayoClinic.com; Hypercalcemia; May 26, 2011
