Kidney cancer is a histologically different variant of malignant neoplastic transformation of renal tissue. Clinical signs are renal symptoms (pain, hematuria, tumor-like formation) and extrarenal (general) manifestations. Diagnosis requires a thorough general clinical, laboratory, ultrasound, X-ray, tomographic, radioisotope examination of the urinary system. Radical or extended nephrectomy is indicated; immunotherapy, chemotherapy, targeted therapy.
Meaning
Kidney cancer accounts for 2-3% of all oncological diseases, and in adult clinical oncourology ranks 3rd after prostate cancer and bladder cancer. It is mainly detected in patients aged 40-60 years, while men are statistically 2-3 times more likely than women. According to modern views, it is a polyethological disease; the development of a tumor can be caused by a variety of factors and influences: genetic, hormonal, chemical, immunological, radiation.
Causes
According to current data, a number of factors affect the incidence of kidney cancer. In renal cell carcinoma, a certain type of mutations was revealed in patients – translocation of the 3rd and 11th chromosomes, and the possibility of inheritance of a predisposition to the occurrence of a tumor process (Hippel-Lindau disease) was also proved. The reason for the growth of all malignant tumors, including those affecting the kidney, is the insufficiency of antitumor immune protection (including DNA repair enzymes, anti-oncogenes, natural killer cells).
Tobacco smoking, abuse of fatty foods, uncontrolled intake of analgesics, diuretics and hormonal drugs significantly increase the risk of kidney cancer. The occurrence of neoplasia can lead to chronic renal failure and regular hemodialysis, polycystic kidney disease, nephrosclerosis, developing against the background of diabetes mellitus, hypertension, nephrolithiasis, chronic pyelonephritis.
Neoplasm can be provoked by chemical effects on the body (in contact with carcinogens – nitrosamines, cyclic hydrocarbons, asbestos, etc.), as well as radiation. Cancer may develop after a previously suffered organ injury.
Classification
Morphological variants of neoplasia are extremely variable, which explains the presence of several histological classifications. According to the histological classification adopted by WHO, the main types of malignant kidney tumors include:
- Renal cell tumors (clear cell carcinoma, tubular carcinoma, medullary carcinoma, papillary carcinoma, granular cell carcinoma, etc.)
- Nephroblastic tumors (nephroblastoma or Wilms tumor)
- Mesenchymal tumors (leiomyosarcoma, angiosarcoma, rhabdomyosarcoma, fibrous histiocytoma)
- Neuroendocrine tumors (carcinoid, neuroblastoma)
- Germinogenic tumors (choriocarcinoma)
The 1997 International TNM classification is common for various types of kidney cancer (T is the size of the primary tumor; N is the prevalence of lymph nodes; M is metastases to target organs).
- T1 – tumor node less than 7 cm, localization is limited to the kidney
- T1a – the size of the tumor node up to 4 cm
- T1b – the size of the tumor node is from 4 to 7 cm
- T2 – the tumor node is more than 7 cm, localization is limited
to the kidney T3 – the tumor node grows into the perinephrine, adrenal gland, veins, but the invasion is limited to the fascia of the Gerot
- T3a – invasion of the paranephral fiber or adrenal gland within the boundaries of the Gerota fascia
- T3b – germination of the renal or inferior vena cava below the diaphragm
- T3c – germination of the inferior vena cava above the diaphragm
- T4 – the spread of the tumor beyond the renal capsule with damage to adjacent structures and target organs.
According to the presence/absence of metastatic nodes, it is customary to distinguish the stages: N0 (there are no signs of lymph node damage), N1 (metastasis is detected in a single regional lymph node), N2 (metastases are detected in several regional lymph nodes). According to the presence / absence of distant metastases, the following stages are distinguished: M0 (distant metastases in target organs are not detected), M1 (distant metastases are detected, usually in the lungs, liver or bones).
Symptoms of kidney cancer
With small sizes, the tumor may be asymptomatic. The manifestations that occur in patients are diverse, among them there are renal and extrarenal symptoms. Renal signs include a triad: the presence of blood in the urine (hematuria), pain in the lumbar region and palpation-determined formation on the side of the lesion. The simultaneous appearance of all symptoms is characteristic of large tumors with a running process; at earlier stages, one or less often two signs are detected.
Renal symptoms
Hematuria is a pathognomonic sign of kidney cancer, it can appear once or periodically already in the early stages of the disease. It can begin unexpectedly, painlessly with satisfactory general well-being, it can be insignificant (microhematuria) and total (macrohematuria). Macrohematuria occurs as a result of damage to blood vessels when the tumor grows into the renal parenchyma, compression of intrarenal veins by it. The excretion of vermiform blood clots in the urine is accompanied by renal colic.
Pain is a late sign of neoplasia. They are dull, aching in nature and are caused by compression of nerve endings during internal invasion of the tumor and stretching of the renal capsule. Cancer is palpated mainly in the third or fourth stages as a dense, lumpy formation. The increase in body temperature is prolonged, the values are often subfebrile, but sometimes high febrile, can range from normal values to elevated. In the early stages, hyperthermia is caused by the body’s immune response to tumor antigens, in the later stages – by the processes of necrosis and inflammation.
Extrarenal symptoms
The extrarenal symptoms of kidney cancer include paraneoplastic syndrome (weakness, loss of appetite and weight, sweating, fever, hypertension), compression syndrome of the inferior vena cava (symptomatic varicocele, swelling of the legs, dilation of the subcutaneous veins of the abdominal wall, deep vein thrombosis of the lower extremities), Stauffer syndrome (liver dysfunction). Kidney cancer in children (Wilms disease) is manifested by an increase in the size of the organ, increased fatigue, thinness, as well as pain of a diverse nature.
Complications
Severe hematuria can lead to anemia, obstruction of the ureter, tamponade of the bladder with blood clots and acute urinary retention. Diverse clinical symptoms may be a manifestation of tumor metastases. Signs of metastasis are cough, hemoptysis (with lung damage), pain syndrome, pathological fractures (with bone metastases), severe headache, increased neurological symptoms, persistent neuralgia and radiculitis, jaundice (with liver metastases).
Diagnostics
In the diagnosis of kidney cancer, general clinical, laboratory, ultrasound, X-ray and radioisotope studies are used. Examination by an oncourologist includes anamnesis collection, general examination, palpation and percussion (Pasternatsky’s symptom). According to the results of a general clinical examination, laboratory diagnostics of blood and urine (general and biochemical analyses, cytological examination) is prescribed.
Changes in laboratory parameters of blood and urine are detected: anemia, increased ESR, secondary erythrocytosis, proteinuria and leukocyturia, hypercalcemia, enzymatic shifts (increased secretion of alkaline phosphatase, lactate dehydrogenase). There is an increased secretion of various biologically active substances by the tumor (prostaglandins, thromboxanes, the active form of vitamin D), hormones (renin, parathyroid hormone, insulin, hCG). An examination of the chest and bones is required to detect metastasis to the lungs and pelvic bones. An instrumental study is being performed:
- Ultrasound of the kidneys. Of paramount importance at the initial stage of diagnostics is ultrasound, which, in the presence of a tumor, reveals deformation of the contours of the organ, inhomogeneity of the echo signal due to the presence of necrosis and hemorrhage zones, sharp absorption of ultrasound by the tumor formation itself. Under the control of ultrasound, a closed percutaneous puncture biopsy of the kidney is performed to collect material for morphological examination.
- X-ray examination. Intravenous urography and renal angiography are performed at the final stage of diagnosis. Signs of a cancerous lesion of the renal parenchyma during urography are an increase in the size of the kidney, deformation of the contours, a defect in the filling of the cup-pelvic system, a deviation of the upper ureteral department; according to the angiogram of the kidneys, an increase in the diameter and displacement of the main renal artery, disorderly excessive vascularization of tumor tissue, heterogeneity of the tumor shadow during its necrosis. Renal angiography helps to differentiate a true neoplasm from a cyst, to identify a small tumor in the cortical layer, the presence of metastases in neighboring organs and the second kidney, a tumor thrombus in the renal vein.
- Radionuclide scanning. Nephroscintigraphy allows you to detect focal changes characteristic of kidney cancer. Due to the different absorption of gamma particles by the normal renal parenchyma and tumor tissue, a partial defect in the image of the renal tissue or its complete absence with a total lesion is created.
- Tomographic examination. CT of the kidney with contrast enhancement makes it possible to detect kidney cancer of any size, to establish its structure and localization, the depth of parenchyma germination, infiltration of paranephral fiber, tumor thrombosis of the renal and inferior vena cava. In the presence of appropriate symptoms, CT scans of the abdominal cavity, retroperitoneal space, bones, lungs and brain are performed in order to detect metastases.
Kidney cancer is differentiated with solitary kidney cyst, urolithiasis, hydronephrosis, nephrolithiasis, abscess and tuberculosis of the kidney, with tumors of the adrenal gland and extraorgan retroperitoneal tumors.
Treatment of kidney cancer
Surgical treatment
Surgical treatment is the main and most effective method in most cases of the disease, it is used even with regional and distant metastases and allows to increase the survival time and quality of life of patients. Kidney removal (radical and extended nephrectomy) and kidney resection are performed. The choice of a therapeutic approach is determined by the variant of neoplasia, the size and localization of the tumor, the predicted survival of the patient.
- Kidney resection. It is carried out in order to preserve the organ in patients with a local form of cancer, when the tumor does not penetrate deep into the parenchyma, is located at the poles, as well as in cases of a single kidney, bilateral tumor process, dysfunction of the second kidney. During kidney resection, intraoperative histological examination of the tissue from the edges of the surgical wound is performed for the depth of tumor invasion. After resection, there is a higher risk of local recurrence of kidney cancer.
- Radical nephrectomy. It is the method of choice at all stages of kidney cancer. It involves surgical excision of a single block of the kidney and all nearby formations: perinephrine fatty tissue, renal fascia, regional lymph nodes. Removal of the adrenal gland is carried out when metastatic foci are found in it.
- Extended nephrectomy. With an extended nephrectomy, the tumor tissues that have spread to the surrounding organs are excised. When the tumor grows into the lumen of the renal or inferior vena cava, a thrombectomy is performed; when the vascular wall is affected by the tumor, a marginal resection of the inferior vena cava is performed. In the case of advanced kidney cancer, in addition to nephrectomy, surgical resection of metastases in other organs is mandatory. Lymphadenectomy with histological examination of the removed nodes helps to establish the stage of cancer and determine its prognosis. In the absence of metastases in the lymph nodes (according to ultrasound, CT), lymphadenectomy may not be performed. Performing radical nephrectomy for cancer of a single kidney requires hemodialysis and subsequent kidney transplantation.
Currently, there is a tendency in kidney cancer surgery to gradually abandon open interventions in favor of laparoscopic and robot-assisted operations.
Conservative treatment
Arterial chemoembolization of the tumor. It can be performed as a preoperative preparation to reduce blood loss during nephrectomy, as a palliative treatment method in inoperable patients or to stop bleeding in massive hematuria.
- Immunotherapy. It is prescribed to stimulate antitumor immunity in advanced and recurrent cancer. Monotherapy with interleukin-2 or alpha-interferon is usually used, as well as combined immunotherapy with these drugs, which makes it possible to achieve partial regression of the tumor (in about 20% of cases), long-term complete remission (in 6% of cases). The effectiveness of immunotherapy depends on the histotype of neoplasia: it is higher in light-cell and mixed cancers and extremely low in sarcomatoid tumors. Immunotherapy is ineffective in the presence of brain metastases.
- Targeted therapy with drugs sorafenib, sunitinib, sutent, avastin, nexavar allows blocking tumor vascular endothelial growth factor (VEGF), which leads to disruption of angiogenesis, blood supply and growth of tumor tissue. Immunotherapy and targeted therapy for advanced cancer can be prescribed before or after nephrectomy and resection of metastases, depending on the intractability of the tumor and the general health of the patient.
- Chemotherapy (with vinblastine, 5-fluorouracil) in metastatic and recurrent kidney cancer, it gives minimal results due to cross-drug resistance, it is usually carried out in combination with immunotherapy.
- Radiation therapy. It does not give the necessary effect, it is used only for metastases to other organs. With a widespread neoplasm with the germination of surrounding structures, extensive metastases to the retroperitoneal lymph nodes, distant metastases to the lungs and bones, only palliative or symptomatic treatment is possible.
Prognosis and prevention
After the treatment, regular monitoring and examination by an oncourologist is indicated. The prognosis of kidney cancer is determined mainly by the stage of the tumor process. With early detection of tumors and metastases, one can hope for a favorable treatment result: the 5-year survival rate of patients with stage T1 after nephrectomy is 80-90%, with stage T2 40-50%, with stage T3-T4, the prognosis is extremely unfavorable – 5-20%. Prevention consists in following a healthy lifestyle, giving up bad habits, timely treatment of urological and other diseases.