Renal damage in solid tumors

　　One, Etiology

　　This disease is caused by tumors. Various tumors can cause glomerular damage, among which, in malignant tumors, the most important are adenocarcinoma of the lung, colon, stomach, and breast; in addition, lymphoma (mainly Hodgkin's disease) and leukemia can also cause glomerular damage.

　　Two, Pathogenesis

　　The main mechanisms of renal damage include direct invasion of the kidney by extrarenal tumors, immune abnormalities mediation, tumor metabolic abnormalities, and side effects during the treatment of tumors (chemotherapy drugs and tumor lysis products). However, the pathogenesis of renal damage caused by tumors and manifested as nephrotic syndrome is mainly mediated by immune abnormalities. The following mainly elaborates on this aspect.

　　The main immunological abnormal mechanism of renal damage caused by tumors is mainly glomerular lesions mediated by immune complexes. It is common in Hodgkin's disease and non-Hodgkin's lymphoma, chronic lymphocytic leukemia, lung cancer, colorectal cancer, breast cancer, and so on. The immunological abnormalities mainly include the following aspects.

　　1, Stimulating the host to produce anti-tumor antibodies by tumor-associated antigens:The formation of antigen-antibody soluble immune complexes can deposit in the glomeruli and cause disease. Some researchers found a case of liver metastasis in a patient with colon cancer complicated with nephrotic syndrome, showing thickening of the renal basement membrane and granular deposition of IgG, IgA, IgM, and C3 along the glomerular capillary wall in renal tissue biopsy. Cancer embryonic antigen (CEA) was extracted from the liver metastatic nodules to immunize sheep, obtaining a pure serum against CEA. The fluorescently labeled anti-CEA serum was used to examine the renal tissue, and diffuse granular deposition of CEA was found on the glomerular basement membrane.

　　2, Immune complex nephritis caused by antigen-antibody complexes:Old-stone reported the detection of immune complexes in the serum of patients with African Burkitt lymphoma, with the detection of EB virus antigen, antibody, and complement deposits in the glomeruli; and tumor virus antigen deposits were found in the mesangium of patients with acute leukemia.

　　3, Pathogenicity caused by non-tumor self-antigens:Higgins reported on patients with disseminated oat cell carcinoma complicated with nephrotic syndrome, detecting antinuclear antibodies in the serum. IgG and C3 deposits were found within the glomerular basement membrane and under the epithelium, showing positive reactions after being stained with DNA-specific dye. At the same time, in the necrotic areas of the tumor and the sites of cancer metastasis, extracellular localized positivity was also observed, indicating that necrotic tumors produce a large amount of tumor cell DNA, causing the body to produce anti-DNA antibodies and form immune complexes, leading to renal damage in patients with tumor disease. This supports the view that patients with tumor disease can produce non-organ-specific autoantibodies.

　　4, Defect in immune surveillance function:The disease is caused by the formation of antigen-antibody immune complexes when patients with tumor disease are exposed to a certain antigen.

　　5, Concomitant minimal change nephropathy in Hodgkin's disease:Some authors believe it is due to a deficiency in the function of T lymphocytes, while some researchers believe it may be due to the production of certain lymphokines or lymphotoxins by tumor cells, leading to increased permeability of the glomerular basement membrane.

　　6, Secondary amyloidosis in tumors:Many malignant tumors can develop secondary amyloidosis, especially renal cell carcinoma, Hodgkin's disease, and chronic lymphocytic leukemia.

　　This disease is one of the complications of tumors, which itself is mainly manifested as nephrotic syndrome. It is most common in renal damage caused by tumors in lung cancer, gastric cancer, breast cancer, and colorectal cancer, including uric acid nephropathy, hypercalcemic nephropathy, hypokalemic nephropathy, acute hyperuricemia-induced acute renal failure (in some cases during tumor chemotherapy), obstructive nephropathy, and so on.

　　In addition to the extrarenal clinical manifestations of the tumor itself, renal damage is mostly manifested as proteinuria or nephrotic syndrome, changes in active urinary sediment or a decrease in glomerular filtration rate, and significant renal damage is not common. If significant renal damage occurs, it is often secondary to proliferative glomerulonephritis.

　　There is no regularity to be found in the sequence of time between the renal damage caused by tumors and the diagnosis of the tumor. There are reports that nephrotic syndrome appeared 14 months before the diagnosis of the tumor, or nephrotic syndrome appeared several months or years after the diagnosis of the tumor. The symptoms of kidney disease may be relieved with the effective treatment of the tumor and worsen with the recurrence of the tumor. Generally, the most common renal glomerular damage caused by adenocarcinoma is nephrotic syndrome.

　　Some people believe that in the primary nephrotic syndrome of membranous nephritis, 6% to 10% may be secondary to occult malignant tumors, lymphoma, and leukemia, which can also cause glomerular damage. Hodgkin's disease most commonly causes minimal change, occasionally acute or chronic nephritis syndrome, nephrotic syndrome is the main clinical manifestation of glomerular damage in Hodgkin's disease. When the clinical condition of Hodgkin's disease fluctuates, proteinuria may increase or decrease accordingly. Renal damage caused by tumors can evolve into chronic renal failure. Renal damage caused by tumors, in addition to glomerular diseases, can also cause uric acid kidney disease, hypercalcemic kidney disease, hypokalemic kidney disease, acute renal failure caused by acute hyperuricemia (in some cases of tumor chemotherapy), obstructive kidney disease, and so on.

　　The prevention of this disease is the same as that of other malignant tumors, which can adopt three levels of prevention.

　　1. The first level of prevention is etiological prevention:The goal is to prevent the occurrence of cancer. The tasks include studying various causes and risk factors of various cancers, taking preventive measures against specific carcinogenic, promoting factors such as chemicals, physics, and biology, and pathogenic conditions inside and outside the body, and taking measures to strengthen environmental protection, appropriate diet, and appropriate sports to enhance physical and mental health.

　　2. The second level of prevention or preclinical prevention:The goal is to prevent the development of primary diseases. It includes early detection, early diagnosis, and early treatment of cancer to prevent or slow down the progression of the disease and reverse it to stage 0 as soon as possible.

　　3. The third level of prevention is clinical (stage) prevention or rehabilitation prevention:The goal is to prevent the progression of the disease and the occurrence of disabilities. The task is to adopt a multidisciplinary comprehensive diagnosis (MDD) and treatment (MDT), correctly select reasonable and optimal diagnostic and treatment plans to extinguish cancer as soon as possible, strive to promote the recovery of function and rehabilitation, prolong life, improve the quality of life, and even return to society.

　　The laboratory abnormalities related to renal damage caused by tumors include:

　　1. Abnormal urinalysis:Large amounts of proteinuria, with urinary protein quantification > 3.5g/24h, and changes in active urinary sediment such as red blood cells, white blood cells, and various casts may occur.

　　2. Renal function examination:There may be a decrease in glomerular filtration rate, with elevated blood BUN and Cr.

　　3. Rapid Erythrocyte Sedimentation Rate:Most patients have ESR>60mm/h, and more than 20% of patients can have ESR exceeding 100mm/h. However, it should be noted that the rapid increase in ESR in patients with nephrotic syndrome cannot be used as a sign to indicate the presence of tumors or certain chronic inflammatory diseases.

　　Secondly, Renal Biopsy

　　1. Light Microscopy Examination

　　(1) The glomerular basement membrane is thickened, presenting as membranous nephropathy.

　　(2) In addition to the thickening of the glomerular basement membrane, there is mesangial proliferation, presenting as mesangiocapillary proliferative glomerulonephritis.

　　(3) Simple Mesangial Proliferative Lesion.

　　(4) Minimal Change Nephrotic Syndrome.

　　(5) Focal Segmental Glomerulosclerosis.

　　2. Immunofluorescence Examination

　　Immunoglobulin IgG, IgA, IgM, and complement C3 are diffusely granular deposited along the basement membrane of the glomerulus, and sometimes also deposited in the mesangial area.

　　3. Electron Microscopy Examination

　　Electronic dense deposits can be seen under the basement membrane of the glomerulus, below the epithelial cells, and in the mesangial area.

　　1. Foods that are good for the body for renal damage in solid tumors

　　Diet should be light, with more vegetables and fruits, and a reasonable diet should be balanced. Pay attention to adequate nutrition. The diet should be high in nutrition, light, and easy to digest, and avoid eating large fish, meat, and overly greasy foods to prevent the middle burner from being constrained, affecting its transformation, and leading to insufficient nutrition.

　　2. Foods to avoid for renal damage in solid tumors

　　Spicy and greasy foods should be avoided.

　　1. Treatment

　　Firstly, the treatment should be aimed at the primary disease - the tumor itself. The various types of renal lesions caused by tumors are generally similar to the treatment of primary renal diseases; the difference is that after active treatment of the tumor, renal lesions can be improved, and even complete remission can be achieved. Adenocarcinoma is best treated by surgical resection, which is very effective and can also alleviate renal damage. Renal damage can also be alleviated after local X-ray radiotherapy of the lymph nodes in Hodgkin's disease or systemic chemotherapy.

　　2. Prognosis

　　This disease is caused by tumors, and its prognosis is consistent with the treatment effect of the primary disease. If the treatment for early diagnosis is correct and complete remission is achieved, the renal lesions can also be improved. Otherwise, the prognosis is poor.