Renal cell carcinoma is a malignant tumor originating from the epithelium lining the renal tubules. The clinic includes general symptoms (malaise, weight loss, subfebrility), local manifestations (macrohematuria, pain, palpable formation) and signs of metastasis. Diagnosis is based on excretory radiography, selective renal angiography, ultrasound, CT and MRI, kidney biopsy. Treatment is determined by the stage of neoplasia, nephrectomy, radiation therapy, chemotherapy, immunotherapy, etc. can be used.
Meaning
Renal cell carcinoma accounts for 3% of cases of all urological neoplasms. In terms of prevalence, kidney cancer ranks third after prostate and bladder cancer, and in terms of the number of deaths it ranks first among them. In recent years, there has been a trend towards a moderate increase in the disease. Men suffer 2-3 times more often than women. Early detection and treatment of kidney cancer is an extremely urgent problem of modern urology. At the time of diagnosis, 25-30% of patients already have distant metastases, another quarter has a locally widespread process. Even after radical nephrectomy, metastases occur in 40-50% of cases in the coming years.
Causes
Despite the prevalence of renal oncopathology, the causes of renal cell carcinoma can only be assumed. One of the most significant etiological factors is smoking, which doubles the likelihood of developing pathology: from 30% in non-smokers to 60% in smokers. It is believed that the formation of a tumor may be associated with some occupational hazards – contact with nitros compounds, asbestos, pesticides, petroleum derivatives, cyclic hydrocarbons, heavy metal salts, ionizing radiation. The relationship between renal cell carcinoma and the abuse of phenacetin-containing analgesics is traced.
Many studies confirm the role of obesity and hypertension in the development of kidney cancer. Risk factors include nephrosclerosis and diseases leading to it (nephrolithiasis, diabetes mellitus, chronic pyelonephritis, tuberculosis, chronic renal failure, etc.). It is considered that neoplasia develops more often in abnormally developed kidneys – horseshoe, dystopian, polycystic, etc. The occurrence of neoplasm may be genetically caused by translocation of chromosomes 3 and 11.
Classification
In the histological classification, several types of cancer are distinguished depending on the cell types encountered: light-cell, glandular (adenocarcinoma), granular-cell, sarcoma-like (polymorphic-cell and spindle-cell), mixed-cell. Macroscopic signs of neoplasia are the spherical shape of the tumor, the location in the cortical layer of the kidney, the absence of a true capsule, peripheral growth, numerous hemorrhages, necrosis, calcifications, fibrous areas.
Clinically important is the staging of renal cell carcinoma in accordance with the TNM classification, where the letter T denotes the primary tumor (tumor), N – regional lymph nodes (nodulus), M – distant metastases (methastases):
- T1 – neoplasm of the largest size up to 7 cm, limited to the kidney and renal capsule
- T2 is a neoplasm over 7 cm, limited to the kidney and the renal capsule
- T3 is a neoplasm of any size that grows into the perinephrine tissue or spreads into the renal or inferior vena cava
- T4 is a neoplasm that grows into the amniotic fascia or neighboring organs.
In stages I-II (T1-T2), there are no lymph node lesions and distant metastases (N0 M0). At stage III, cancer cells are detected in the nearby lymph node. Stage IV of renal cell carcinoma can be characterized by any value of T in the presence of affected lymph nodes or distant metastases (N1 or M1). TNM classification allows you to determine the therapeutic tactics and prognosis.
An invasive neoplasm can squeeze or germinate into the stomach, pancreas, liver, intestines, spleen. Renal cell carcinoma can metastasize by hematogenic mechanism (to another kidney, adrenal glands, liver, lungs, bones, skull, brain) and lymphogenic pathway (to aortocaval, paraaortic, paracaval lymph nodes, mediastinum). It is characterized by the spread in the form of a tumor thrombus along the venous highways up to the right atrium.
Renal cell carcinoma symptoms
Clinical signs are characterized by a classical triad: hematuria, pain and palpable neoplasm. Hematuria can be micro- and macroscopic. More often, against the background of a generally satisfactory condition, sudden total, painless hematuria develops, which, as a rule, is noted once or lasts for several days, and then suddenly stops. If hematuria is accompanied by the discharge of shapeless or worm-like blood clots, obstruction of the ureter may occur with the development of a painful attack resembling renal colic. Repeated episodes of hematuria may occur after several days or months.
The nature of pain in renal cell carcinoma depends on the changes that occur. Acute paroxysmal pains occur due to occlusion of the ureter by a blood clot, hemorrhage into the tumor tissue or kidney infarction. Constant aching dull pains can be caused by compression of the pelvis by a tumor, germination of the renal capsule, paranephria and fascia of the Gerota, adjacent muscles and organs, secondary nephroptosis. Pain can radiate to the genitals and hip, simulating sciatic nerve neuralgia.
The palpable tumor can be determined from the side of the abdomen or lower back in the form of a dense or elastic lumpy or smooth formation. This sign is detected in the late stages of kidney cancer. Extrarenal symptoms appear quite early – arterial hypertension, fever, intoxication, weight loss, anorexia, myalgia, arthralgia, dyspepsia, etc. Of the local symptoms in men, varicocele is often found, caused by compression or thrombosis of the NSAID, testicular or renal vein.
Diagnostics
Kidney cancer is diagnosed based on the results of complaints, objective examination, laboratory, endoscopic, ultrasound, X-ray, tomographic, radioisotope examination, morphological examination of the biopsy of tumor tissues and metastatic lymph nodes. Erythrocytosis, anemia, acceleration of ESR, hyperuricemia, hypercalcemia, Stauffer syndrome are noted in the blood. Cystoscopy performed at the time of hematuria allows you to find out the source of bleeding and the side of localization of the tumor.
Ultrasound of the kidneys is the first instrumental examination for suspected renal cell carcinoma. Characteristic echographic signs are an increase in the size of the kidney, uneven contours, a change in the echostructure, deformation of the renal sinuses and cup-pelvic complexes. Ultrasound of renal vessels allows to determine the nature of tumor vascularization and vascular involvement.
Intravenous urography allows us to judge only indirect signs of kidney cancer, but it gives valuable information about concomitant changes (anomalies, kidney stones, hydronephrosis, the condition of the opposite kidney). Renal angiography is performed to visualize tumor thrombi. MRI and CT of the kidneys are used as an alternative to excretory urography and renal angiography. With the help of tomography, it is possible to get an accurate idea of the stage of neoplasia and determine the therapeutic tactics. Radioisotope nephroscintigraphy and positron emission tomography help to assess the functioning of a healthy and affected kidney.
Differential diagnosis is carried out with nephroptosis, hydronephrosis, polycystic kidney disease, pionephrosis, abscess, etc. Crucial in doubtful situations belongs to kidney biopsy and morphological examination of the biopsy. Detection of metastases in distant organs is possible with the help of chest X-ray, bones, ultrasound of the abdominal cavity.
Renal cell carcinoma treatment
The only radical method of treating pathology is nephrectomy. Simple nephrectomy involves removal of the kidney and paranephral tissue; radical nephrectomy involves additional removal of the adrenal gland and fascia, paracaval and paraaortic lymphadenectomy; extended nephrectomy – resection of other affected organs. Nephrectomy in renal cell carcinoma is performed by transperitoneal, thoraco-abdominal or laparoscopic access.
With metastasis of the neoplasm in the bones of the skeleton, amputation, exarticulation of the limb, rib resection, etc. can be performed. Excision-accessible metastases in the liver, lungs, and lymph nodes are also subject to surgical removal. In addition to radical nephrectomy, as well as inoperable renal cell carcinoma and its relapses, it is advisable to conduct radiation therapy, hormone therapy, chemotherapy, immunochemotherapy, general hyperthermia.
Prognosis and prevention
An important criterion for long-term prognosis is the prevalence of renal cell carcinoma. Current data indicate that with radical removal of stage I kidney cancer, the 5-year survival rate is close to 70-80%, stage II – to 50-70%, stage III — to 50%, stage IV — less than 10%. Dispensary observation and control examination of patients is carried out by a nephrologist. Prevention involves the exclusion of risk factors that increase the likelihood of neoplasia.