Renal failure in cancer

Almost a third of patients suffering from oncological diseases and admitted to the intensive care unit are found to have renal dysfunction. In this case, most often, in approximately 80% of cases, various tubular dysfunctions are observed. In 10% of cases, nephropathy manifests itself as severe acute renal failure or chronic renal failure, the treatment of which involves renal replacement therapy.

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Causes of Kidney Failure in Cancer

Nephropathy develops as a result of various operations, extensive blood loss, the use of nephrotoxic drugs and specific causes in oncological diseases:

• Surgical intervention involving resection of a single kidney, or nephrectomy, increases the functional load on the remaining kidney.
• Resection and plastic surgery of the ureters and bladder leads to disruption of the outflow and absorption of urine from the intestine.
• Resection and plastic surgery of the inferior vena cava and renal veins due to tumor thrombosis or retroperitoneal tumors provokes thermal ischemia during surgery and/or blood flow disorders in the postoperative period.
• Surgical intervention accompanied by extensive tissue trauma, blood loss and unstable hemodynamics, which requires the use of catecholamines intraoperatively and in the early postoperative period, contributes to the development of nephropathy.
• Use of nephrotoxic drugs (antibiotics, dextrans, etc.). Nephropathy is manifested by an increase in the level of creatinine and urea (by 1.5-2 times), a decrease in the rate of diuresis to 25-35 ml/h. Less often, a moderate increase in the level of K+ is observed, not exceeding 5.5-6 mmol/l.
• Specific causes of nephropathy in tumor diseases are most often associated with obstruction of the urinary tract or large renal vessels by the tumor, nephrotoxic effects of antitumor drugs and supportive therapy drugs, disturbances in electrolyte and purine metabolism during antitumor treatment, replacement of renal parenchyma with tumor tissue, and radiation damage to the kidneys.

Possible causes of renal failure associated with the presence of a tumor disease

	Tumor-related causes	Causes related to antitumor treatment
Prerenal	Hypovolemia and critical hypotension (bleeding, extrarenal fluid loss due to vomiting or diarrhea, fluid extravasation due to polyserositis, etc.) Obstruction of the vessels of the renal pedicle by a tumor node or a tumor thrombus of the renal veins	Complications of the postoperative period leading to the development of shock Severe sepsis, extrarenal fluid loss due to vomiting or diarrhea Thrombotic microangiopathy Hepatorenal thrombosis
Renal	Tubulointerstitial nephritis (with hypercalcemia and hyperuricemia) Infiltration of the kidneys by a tumor (kidney cancer, lymphoma, leukemia) Glomerulonephritis Amyloidosis	Nephrectomy or resection of the only functioning kidney Nephrotoxic effect of chemotherapy drugs (cisplatin, methotrexate, etc.), adjuvant drugs (amphotericin B, aminoglycosides, bisphosphonates, hyperosmolar radiocontrast agents) Uric acid nephropathy in rapid tumor lysis syndrome
Postrenal	Obstruction of the urinary tract by a tumor (retroperitoneal and pelvic tumors, prostate cancer, bladder cancer) Tamponade of the bladder due to bleeding from a tumor High intra-abdominal pressure (ascites)	Nephrolithiasis due to hypercalcemia, hyperuricemia Bladder tamponade

The causes of ARF are usually the same as those of nephropathy, but they act to a greater extent. Acute tubular necrosis is the basis of most cases of ARF, in particular in 80% of cases of the disease occurring in intensive care units. The cause of acute renal failure in 50% of cases is ischemic, and in 35%, toxic kidney damage. The main cause of acute tubular necrosis in sepsis is severe renal hypoperfusion.

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How does kidney failure develop in cancer?

The pathophysiological basis of acute renal failure in cancer is local hemodynamic and ischemic disturbances, as well as toxic damage to tubular cells. In accordance with these disturbances, the glomerular filtration rate decreases as a result of intrarenal vasoconstriction with a decrease in glomerular filtration pressure, tubular obstruction, transtubular filtrate leakage, and interstitial inflammation.

In tubular necrosis, as a rule, after 2-3 weeks, renal function is restored, urea and creatinine levels progressively decrease, and the clinical picture.

The clinical picture of acute renal failure is manifested by an increase in the level of creatinine and urea (more than 2-3 times), an increase in the level of potassium in the blood (more than 6 mmol/l), and a decrease in the rate of diuresis (less than 25 ml/h).

Classification

Renal dysfunctions developing in the postoperative period are classified into two large groups, which determine further diagnostic and treatment tactics in the intensive care unit - nephropathy and acute renal failure in cancer.

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Diagnosis of renal failure in cancer

Diagnosis is facilitated not only by the results of clinical and instrumental examination, but also by data obtained as a result of collecting anamnesis and analyzing previous treatment.

Diagnostic tactics for nephropathy include:

• conducting a biochemical blood test (urea and creatinine levels),
• blood acid-base balance analysis (pH and electrolyte levels),
• general urine analysis,
• determination of creatinine clearance (as a dynamic indicator and for calculating drug doses),
• Ultrasound of the kidneys (with assessment of the state of renal blood flow, parenchyma and renal pelvis system),
• bacteriological examination of urine (to exclude exacerbation of chronic pyelonephritis).

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Indications for consultation with other specialists

Adequate assessment of the cause of acute renal failure, the scope of additional examination and effective treatment require coordinated work of intensive care specialists, nephrologists (determining the scope of nephrological care and providing renal replacement therapy) and oncologists. However, less than half of cases of severe ARF are associated with specific (tumor) causes, in 60-70% of cases of acute renal failure it develops as a result of shock and severe sepsis.

Treatment of kidney failure in cancer

The main condition for successful treatment of nephropathy and ARF in operated patients is the elimination or minimization of the maximum possible number of causes that contribute to their development. When considering the tactics of treating acute renal failure, attention should be paid to the rate of creatinine and potassium increase, the total amount of urine and the presence of clinical data on the patient's volume overload, i.e. the threat of OL.

Non-drug treatment

Intensive therapy of acute renal failure, in addition to conservative methods used in nephropathy, includes extracorporeal detoxification. The choice of extracorporeal detoxification method, its duration and frequency depend on the clinical situation:

• isolated OPN - GD,
• ARF as part of PON, against the background of sepsis, with the addition of ARDS - HDF,
• prevalence of fluid overload in the patient (including the threat of acute pulmonary embolism) - isolated UF.

The choice between a prolonged or discrete regimen of extracorporeal detoxification is determined primarily by the severity of acute renal failure, as well as the state of the hemostasis (hypocoagulation, thrombocytopenia) and hemodynamic systems (need for catecholamines, cardiac arrhythmia).

Drug treatment

Key points for the correction of nephropathy as part of intensive care:

• Maintaining adequate renal blood flow, sufficient circulating blood volume, epidural block.
• Improving the rheological properties of blood (disaggregants, low molecular weight heparins).
• Prescription of specific amino acid solutions and enteral nutrition (“-nephro”, “-renal”).
• Taking lactulose preparations orally, if possible.
• Stimulation of diuresis as indicated (furosemide or osmotic diuretics).

The administration of dopamine in the so-called “renal dose” (1-3 mcg/kg x min) does not lead to a decrease in creatinine levels, but in most elderly patients with renal vascular atherosclerosis it causes an increase in the rate of diuresis (the water excretory function increases), which is important when conducting infusion therapy.

Correction of PON, such as hypotension, respiratory and liver failure, pancreatitis, anemia (less than 8-8.5 g/dl), since organ dysfunction aggravates nephropathy and leads to the development of ARF.

Sanitation of extrarenal and renal foci of infection.

Prescribing nephrotoxic drugs only when absolutely necessary.

Prognosis of renal failure in cancer

The duration of nephropathy usually does not exceed 5-7 days, further development of the clinical situation leads either to its resolution or to the development of acute renal failure. According to a French multicenter study, acute renal failure is diagnosed in 48% of septic patients with a mortality rate of 73% in this group. Sepsis remains one of the main causes of acute renal failure, despite significant advances in intensive care, the mortality rate of patients with this pathology has not changed in recent decades, remaining very high.