Chemotherapy is a common and effective cancer treatment designed to destroy rapidly dividing cancer cells. While these powerful medications target cancerous growths, they can also affect healthy cells and organs. The kidneys, which filter waste and maintain fluid balance, are among the organs that can be impacted. This article explores how chemotherapy can affect kidney health, how damage is identified, and strategies to protect kidney function during treatment.
How Chemotherapy Can Affect Kidneys
Chemotherapy drugs can damage the kidneys through several mechanisms, broadly termed nephrotoxicity. One primary way is direct toxicity to kidney cells, particularly those in the renal tubules. For example, cisplatin, a widely used platinum-based chemotherapy, causes injury to renal cells, affecting the tubules, glomeruli, and blood vessels. This direct cellular damage can lead to acute kidney injury (AKI), characterized by a sudden decline in kidney function.
Some chemotherapy agents can also lead to crystal formation within the kidney tubules, blocking filtration pathways. High doses of methotrexate can cause AKI due to crystal precipitation. This blockage impairs the kidney’s ability to filter blood effectively, leading to a buildup of waste products. The impact on kidney function varies depending on the type and dose of the chemotherapy drug administered.
Certain chemotherapy drugs can affect the blood vessels supplying the kidneys, leading to reduced blood flow, a condition known as ischemia. This can occur through mechanisms like vasoconstriction, where blood vessels narrow, or damage to small blood vessels. Reduced blood flow deprives kidney cells of oxygen and nutrients, impairing their function. Kidneys are a major elimination pathway for many anticancer drugs, making them susceptible to damage as they process and excrete these compounds.
Identifying Chemotherapy-Induced Kidney Issues
Recognizing signs of kidney problems during or after chemotherapy is important for timely intervention. Patients may experience changes in urination patterns, such as producing less urine, or notice swelling in their hands, ankles, or feet. Other symptoms can include fatigue, nausea, or a metallic taste in the mouth. These symptoms indicate that the kidneys may not be functioning effectively.
Healthcare providers routinely monitor kidney function throughout chemotherapy to detect issues early. Common blood tests measure creatinine and blood urea nitrogen (BUN) levels. Creatinine is a waste product produced by muscles, and elevated levels indicate impaired kidney filtration. Similarly, BUN is a waste product from protein breakdown, and high levels suggest that the kidneys are not adequately clearing waste.
Urine tests are also used to assess kidney health. Urinalysis can reveal abnormalities like protein in the urine, which indicates damage to the kidney’s filtering units. Monitoring these markers regularly allows doctors to track kidney function and identify any decline, enabling them to make necessary adjustments to treatment plans.
Protecting Kidney Health During Chemotherapy
Several strategies are employed to minimize the risk of kidney damage for patients undergoing chemotherapy. Adequate hydration is a primary protective measure, often involving intravenous fluids given before, during, and after treatment. This helps flush chemotherapy drugs and their metabolites through the kidneys more quickly, reducing their concentration and potential for toxicity. Increased fluid intake also helps prevent the formation of crystals in the tubules for certain drugs.
Doctors may adjust chemotherapy dosages based on a patient’s kidney function. If kidney function is already compromised, a lower dose might be administered to prevent further damage while still aiming for effective cancer treatment. This individualized approach helps balance the need to treat cancer with the goal of preserving kidney health. In some cases, specific protective medications, known as nephroprotectants, may be administered.
Managing pre-existing conditions that can affect kidney health is also important. Conditions such as diabetes and high blood pressure can independently contribute to kidney damage. Close management of these conditions before and during chemotherapy helps reduce the overall burden on the kidneys and lowers the risk of chemotherapy-induced complications.