The tumor of kidney is one of the more common tumors of the urinary tract and is mostly malignant. Common clinical renal tumors include renal cell carcinoma arising from the renal parenchyma, nephroblastoma, and migratory cell papillary tumors arising from the renal pelvis and calyces. Renal tumors account for 2% to 3% of adult malignancies, while nephroblastoma is the most common solid malignancy in infants and children, accounting for about 20% of malignancies in infants and children.
Disease Introduction
Renal tumors can be classified into many types, and the clinical manifestations and prognosis of different types vary greatly. The most common classification method is to divide renal tumors into two categories: benign and malignant. Common benign renal tumors include simple renal cysts and renal sebaceous adenoma. Malignant renal tumors in adults commonly include renal cell carcinoma and renal pelvis carcinoma, while in infants and children the most common is nephroblastoma.
Morbidity
The incidence of different renal tumors varies, but the overall trend is increasing year by year. This trend may be related to the wide application of imaging technology and the promotion and popularity of routine medical checkups.
Renal tumors can occur at any age, with different proportions in men and women. Among them, malignant tumors are most often seen in people younger than 10 years old and 50-70 years old. In adults, renal cancer and papillary carcinoma of the renal pelvis are the most common, while in infants and children, the incidence of nephroblastoma is the highest. Sarcomas, fibrosarcomas, liposarcomas, and smooth muscle sarcomas are rare, but are highly malignant.
Risk factors
The etiology of renal tumors is still unknown, but risk factors associated with their occurrence include
1, smoking Smoking can increase the risk of kidney tumor and correlate with the amount of smoking, this correlation can decrease after 25 years of stopping smoking.
The prevalence of renal tumors is higher in practitioners of cadmium exposure. The prevalence of kidney tumor is relatively high among coke oven workers, printers and workers engaged in petrochemical work.
3. urban-rural and cultural-economic status Some data confirm that the prevalence of renal tumor is higher among urban residents than rural residents.
Hormones and drugs The use of chemicals, especially hormones, can increase the prevalence of kidney tumors.
5.Other factors Patients on long-term dialysis with renal insufficiency are prone to kidney cancer. In addition, obesity, diabetes, history of blood transfusion, radiation, alcohol consumption, food and other factors may be related to the development of kidney tumor.
Genetic factors
Kidney tumors can be divided into two categories: sporadic and hereditary, among which hereditary kidney cancer accounts for about 4% of renal cell carcinoma. The hereditary renal cancers that have been identified include: von Hipple-Lindau disease (VHL disease), hereditary papillary renal adenocarcinoma, hereditary smooth muscle tumor disease renal cancer, BHD (Birt-Hogg-Dube) syndrome, etc. The clinical manifestations of hereditary renal cancer are characterized by early age of onset, multiple incidences in both kidneys, slow progression, late metastasis and relatively good prognosis.
VHL disease is the most common hereditary kidney cancer, which is an autosomal dominant disease with an incidence of about 1/36,000. clinical manifestations include multiple masses in the central nervous system and abdominal organs. common lesions include cerebellar hemangioblastoma, retinal hemangioma, renal cancer or renal cyst, pancreatic tumor or cyst, pheochromocytoma, etc.
Disease classification
The pathological types of renal tumors are complex and diverse. Historically, there are several classification standards for renal tumors, and the naming and classification methods of renal tumors in each classification standard are different.
In 1998, WHO introduced the second edition of kidney tumor classification method, which has been widely used in China. This standard classifies kidney cancer according to its histomorphology, genetics, tissue origin and other characteristics.
In 2004, WHO introduced the third edition of the pathological classification of renal tumors based on the histomorphological, immunophenotypic and genetic characteristics of renal tumors, combined with the clinical manifestations and imaging changes of renal tumors (Table II), which combines the advances in molecular biology and immunohistochemistry and provides a more refined classification of tumors and better reflects the clinical characteristics of tumors, and is gradually being popularized in China. It is gradually being used in China.
Clinical Performance
The clinical manifestations of different types of renal tumors vary greatly. Common symptoms include.
1. pain in the lower back, hematuria and abdominal masses caused by the tumor itself.
2, compression symptoms caused by tumor enlargement: gastrointestinal symptoms may appear when tumor compresses stomach and duodenum.
3, systemic symptoms: hypertension, anemia, weight loss, fever, erythrocytosis, hyperglycemia, abnormal blood clotting mechanism and other changes.
4.Other: symptoms and signs of acute abdomen such as intra-abdominal hemorrhage, shock and acute abdominal pain may appear when the tumor ruptures due to trauma and other factors.
Disease diagnosis
The clinical manifestations of different kinds of renal tumors are different, and the diagnosis should be based on their specific symptoms and signs for differentiation. In addition, necessary medical tests play an important role in the diagnosis and differentiation of various types of renal tumors.
Laboratory tests
Routine laboratory tests include routine blood and urine tests, blood biochemistry and blood tumor marker tests.
For benign renal tumors such as reninoma, blood biochemistry and endocrine examination can detect abnormalities such as hyperreninemia, hyperaldosteronism and hypokalemia; for malignant renal tumors such as pelvic cancer, urine exfoliative cytology examination plays an important role and may detect shed cancer cells.
Imaging examination
1) Chest X-ray is a routine examination item for patients, and frontal and lateral chest films should be taken to clarify whether there are lung metastases such as lung nodules and other chest lesions.
Ultrasound examination is the most commonly used examination method to diagnose renal tumor, which is non-invasive, accurate and relatively inexpensive, and the ultrasound echo can reflect the histological characteristics of the tumor and play an important role in tumor identification. Renal malformation tumor is a benign kidney tumor with fat-based composition, which shows high echogenicity in ultrasound examination; renal cell carcinoma is a parenchymal tumor without fat-based composition, which shows low echogenicity in ultrasound examination. Therefore, ultrasound examination becomes an important method to distinguish malignant tumor and renal cancer.
3）.CT CT is the most important imaging means for kidney tumor, with the characteristics of high density and spatial resolution, and the detection rate of kidney mass is high, close to 100%.
The irregular shape of the mass, beyond the renal fascia and the discovery of lymph node metastasis or venous tumor embolism all suggest malignancy; if the tumor has complete envelope, clear demarcation with normal tissues and fatty density tissue, it is more likely to be benign.
4）.MRI In the diagnosis of malignant renal tumor, MRI is of great value in determining the scope of renal tumor and whether it is the primary tumor; in addition, MRI can clarify the spread and metastasis of renal tumor, which is important for tumor staging and plays an important role in the later treatment of patients.
(5), intravenous pyelogram A means to diagnose the cause of hematuria, but its sensitivity and specificity for renal parenchymal tumors is poor. The test is contraindicated in patients with iodine allergy, severe liver and kidney and cardiovascular diseases.
(6) Renal arteriography has limitations in the diagnosis of renal tumors. The presence or absence of new blood vessels may be helpful for the diagnosis of renal cell carcinoma.
Nuclear medicine examination
Nuclear bone scan can detect bone metastases 3~6 months earlier than X-ray examination, with high sensitivity but poor specificity and high false positive rate.
Histological examination
The use of puncture biopsy for the diagnosis of renal tumors is controversial. At present, the diagnosis of renal mass puncture biopsy is mainly used to exclude some diseases that are not treated by surgery as the first choice, including infected foci such as abscesses, metastases from extra-renal tumors and lymphomas; it is also used to clearly diagnose the histological staging of renal cancer that has spread and metastasized or retroperitoneal masses that are difficult to be removed, in order to guide the treatment plan, etc.
Disease treatment
Renal tumor treatment should be selected according to the nature of the tumor, systemic status, and other treatment options. Small, asymptomatic benign tumors can be selected for observation and waiting, while the main treatment methods for other renal tumors are surgery, drugs, physical therapy, etc.
Surgical treatment
1 Surgical treatment for benign renal tumor
Whether to perform surgery for benign renal tumor depends on the patient’s symptoms, tumor size and general status of the patient. The principle of surgery is to preserve the kidney function of patients.
2 Surgical treatment for malignant renal tumor
(1) Surgery is the main treatment for limited and locally progressive renal malignant tumors. The choice of surgery includes radical nephrectomy and kidney unit preservation surgery. Principles of surgical treatment.
(1) Surgery to preserve the renal unit is indicated for patients in whom radical nephrectomy would result in functional anephritis and necessitate dialysis. This includes patients with bilateral renal tumors, isolated kidneys, renal insufficiency, and some smaller unilateral tumors, and is particularly suitable for patients with tumors located in the upper or lower pole or margin of the kidney.
(ii) Regional lymph node dissection is an optional procedure.
③If the tumor does not involve the adrenal gland, the adrenal gland can be preserved in the case of non-high risk adrenal metastasis judged by the size and location of the tumor. (iv) Resection of the ipsilateral adrenal gland only in case of suprarenal pole tumor, giant tumor or CT showing abnormalities in the adrenal gland.
(4) Patients with extensive tumor invasion of the inferior vena cava need to be operated with the assistance of a vascular surgeon.
(2) Some patients with metastatic renal tumor can also be considered for surgery
(i) Patients with minimal lesions in regional lymph nodes can receive surgical treatment.
(ii) Patients with a small proportion of primary foci and single isolated metastases with surgical possibilities: e.g. patients with primary RCC and single isolated metastases at initial diagnosis and isolated recurrence or metastases at nephrectomy may undergo nephrectomy plus metastasectomy.
(iii) In patients with primary foci combined with multiple metastases, subtractive nephrectomy may be recommended prior to systemic therapy if surgery is possible for the primary foci. Patients with only pulmonary metastases, better prognostic factors and good physical status scores are most likely to benefit from nephrectomy prior to systemic therapy.
Drug therapy
Up to now, the treatment options for metastatic renal tumors are cytokine therapy, chemotherapy and the newly emerged molecular targeted therapy.
Cytokine therapy: Cytokine therapy has been used as standard therapy for many years. For patients with small tumor size or predominantly pulmonary metastases, high-dose IL-2 therapy can be tried, and tumor progression-free survival (PFS) can be prolonged by more than one times compared with that of patients taking placebo.
Chemotherapy: Kidney cancer has multidrug resistance genes and is not sensitive to chemotherapy. Chemotherapy is only used as an adjuvant treatment for metastatic non
adjuvant treatment for metastatic non-clear cells.
Targeted therapy: The targeted drugs that have been applied in clinical practice are: sorafenib benzoate and tyrosine kinase inhibitor sunitinib malate, etc. Patients who underwent targeted therapy demonstrated longer overall survival and good tolerability. Molecular targeted therapy has shown efficacy in metastatic renal tumors, opening up a new era in the treatment of renal malignancies.
Physical Therapy
For elderly or frail patients who are unable to undergo surgical treatment, they may choose to receive radiofrequency ablation or cryoablation if the tumor is small. [1-3]
Disease Prognosis
The management of postoperative renal tumor with close observation and follow-up is the standard management of postoperative malignant renal tumor. The purpose of follow-up is to check for recurrence, metastasis and neoplastic tumors.
The most important factors in the prognosis of malignant renal tumors are pathological stage and histological grading. In addition, the patient’s general condition, symptoms, the presence of tissue necrosis in the tumor, and abnormal biochemical parameters are also related to the prognosis of kidney cancer. The prognosis of type I renal papillary carcinoma and suspicious cell carcinoma is generally better than that of clear cell carcinoma, while the prognosis of collecting duct carcinoma is mostly worse than that of clear cell carcinoma.