OVERVIEW
Kidney damage during treatment of malignant tumors is a renal disease in which acute kidney injury, chronic renal failure, and abnormal renal tubular function are caused by the development of the tumor itself or by therapeutic drugs or measures in the course of tumor treatment.
Etiology
1. Renal damage caused by malignant tumor
Extra-renal malignant tumors invade the kidney, abnormal metabolism of malignant tumors and deposition of immune complexes may lead to renal damage.
2. Renal damage caused by tumor treatment measures
Non-steroidal anti-inflammatory drugs, cyclosporine, cisplatin, mitomycin, methotrexate, isocyclophosphamide and other drugs, and graft-versus-host disease after hematopoietic stem cell transplantation may cause renal damage.
Symptoms
1. Tumor lysis syndrome
Clinical manifestations are hyperuricemia, hyperphosphatemia, hypocalcemia, hyperkalemia and acute kidney injury.
2. Hemolytic uremic syndrome-thrombotic thrombocytopenic purpura
Patients may have microangiopathic hemolysis, thrombocytopenia and acute kidney injury, i.e. hemolytic uremic syndrome. If there is hemolytic uremic syndrome-like manifestations combined with fever and impaired consciousness, it is consistent with thrombotic thrombocytopenic purpura.
3. Acute tubulointerstitial nephropathy syndrome
Acute renal injury as a prominent manifestation, urinalysis without obvious proteinuria and microscopic hematuria, often without hypertension. Most of them are caused by cisplatin, methotrexate and other drugs leading to acute tubular injury.
4. Proteinuria of glomerular origin
Proteinuria occurs in the course of treatment, and some patients may present with massive proteinuria or nephrotic syndrome.
5. Chronic kidney disease
The history of the disease is more than 3 months, often found during follow-up or physical examination, the course of the disease is prolonged, and may slowly progress to end-stage renal disease.
Examination
During the course of treatment, tumor patients should have regular examination of urine routine and renal function in order to find out the abnormalities of urine and renal impairment and other signs of renal injury in time. Kidney biopsy should be done when necessary.
Diagnosis
Diagnosis of different types of renal injury should be made by combining patients’ tumor history, treatment stage and clinical manifestations.
1. In the initial stage of tumor treatment, those who have acute kidney injury can refer to the diagnostic criteria of tumor lysis syndrome to clarify whether it is tumor lysis syndrome. Laboratory diagnostic criteria of tumor lysis syndrome are that within 3d before treatment and after 7d of chemotherapy, patients have 2 or more abnormal tests: ① blood uric acid ≥476μmol/L or more than 25% of the basal value; ② blood phosphorus ≥1.45mmol/L or more than 25% of the basal value; ③ blood potassium ≥6.0mmol/L or more than 25% of the basal value; ④ blood calcium ≤1.75mmol/L or reduced by more than 25% of the basal value. Tumor lysis syndrome can be clinically diagnosed if the patient meets the laboratory diagnostic criteria and has one of the following clinical manifestations: ① the increase of blood creatinine is more than 1.5 times of the upper limit of the normal value; ② cardiac arrhythmia or sudden death; ③ convulsions.
(2) When proteinuria or chronic kidney disease occurs in tumor patients in the course of long-term treatment, it is necessary to be alert to graft-versus-host disease and bisphosphonate-associated renal disease, and renal biopsy is helpful for diagnosis.
Treatment
Different types of renal injury should be treated accordingly.
1. For acute kidney injury suspected to be caused by chemotherapeutic drugs, stop using the suspected drugs if the condition permits.
2. For nephrotic syndrome, glucocorticoids and/or immunosuppressants may be given.
3. For hematopoietic stem cell transplant recipients, increase the dose of anti-rejection drugs can be considered.
4. Angiotensinase-converting enzyme inhibitors, glucocorticoids, heparin and statins may be given for the treatment of chronic kidney disease.
Prevention
1. Correct reversible factors such as volume insufficiency, hypercalcemia and urinary tract obstruction that cause renal insufficiency.
2. Prophylactic uric acid-lowering therapy and hydration therapy.
3. Use nephrotoxic drugs with caution.
4. Take sodium bicarbonate orally to alkalize the urine to prevent uric acid deposition in the kidney.
5. Regular testing of urine routine and renal function.