What tests should be done for kidney cancer?

The cause of kidney tumors is still unclear. Ethnicity and geographical conditions are not important factors in causing kidney tumors. There are reports that aromatic hydrocarbons, aromatic amines, aflatoxins, hormones, radiation and viruses can cause kidney cancer; certain hereditary diseases such as tuberous sclerosis and multiple neurofibromatosis can be combined with renal cell carcinoma; renal cell carcinoma combined with renal pelvic cancer may be related to local long-term chronic stimulation. Below we will introduce you to what tests should be done for kidney cancer.

1. General examination: Hematuria is an important symptom, and polycythemia often occurs in 3% to 4%; progressive anemia may also occur. In bilateral renal tumors, total renal function usually does not change, and the erythrocyte sedimentation rate increases. Some renal cancer patients do not have bone metastasis, but may have symptoms of hypercalcemia and increased serum calcium levels. After renal cancer resection, the symptoms are quickly relieved and the blood calcium returns to normal. Sometimes it may develop into liver dysfunction, which can return to normal if the tumor kidney is removed.

2. X-ray angiography is the main method for diagnosing renal cancer

(1) X-ray films: X-ray films can show that the kidney is enlarged and its contour is changed. Occasionally, there is tumor calcification, which may be localized or widespread flocculent shadows within the tumor. It may also form calcification lines or shells around the tumor. Kidney cancer is more common in young people.

(2) Intravenous urography. Intravenous urography is a routine examination method. However, it cannot show tumors that have not yet caused deformation of the renal pelvis and calyces, and it is difficult to distinguish whether the tumor is renal cancer, renal angiomyolipoma, or renal cyst. Therefore, its importance is reduced. Ultrasound or CT examination must be performed at the same time for further identification. However, intravenous urography can understand the function of both kidneys and the condition of the renal pelvis, calyces, ureters, and bladder, which has important reference value for diagnosis.

(3) Renal artery angiography: Renal artery angiography can detect tumors that are not deformed by urinary system angiography. Renal cancer manifests itself in neovascularization, arteriovenous fistulas, pooling of contrast agents, and increased capsular blood vessels. Angiography varies greatly, and sometimes renal cancer may not be visualized, such as tumor necrosis, cystic changes, arterial embolism, etc. During renal artery angiography, adrenaline can be injected into the renal artery when necessary to cause normal blood vessels to contract while tumor blood vessels do not react. This is the case for relatively large renal cancers. Selective renal artery angiography can also be followed by renal artery embolization, which can reduce bleeding during surgery. Renal artery embolization can be performed as a palliative treatment for patients with renal cancer that cannot be surgically removed and who have severe bleeding.

3. Ultrasound scanning: Ultrasound examination is the simplest and non-invasive examination method and can be used as part of routine physical examination. Any mass in the kidney that is larger than 1 cm can be found by ultrasound scanning. It is important to distinguish whether the mass is renal cancer. Renal cancer is a solid mass. Because it may have bleeding, necrosis, and cystic changes inside, the echo is uneven and generally low-echo. The boundary of renal cancer is not very clear, which is different from renal cysts. Space-occupying lesions in the kidney may cause deformation or rupture of the renal pelvis, calyx, and renal sinus fat. Renal papillary cystadenocarcinoma looks like a cyst on ultrasound examination and may have calcification. When it is difficult to distinguish between renal cancer and cysts, puncture can be performed. Puncture under ultrasound guidance is relatively safe. The puncture fluid can be examined for cytology and cyst contrast. The cyst fluid is usually clear, free of tumor cells, and low in fat. When the cyst wall is smooth during contrast imaging, it can be confirmed that it is a benign lesion. If the puncture fluid is bloody, a tumor should be considered. Tumor cells may be found in the aspirate. When the cyst wall is not smooth during contrast imaging, it can be diagnosed as a malignant tumor. Renal angiomyolipoma is a solid tumor in the kidney. Its ultrasound manifestation is a strong echo of fat tissue, which is easy to distinguish from renal cancer. When renal cancer is found by ultrasound examination, attention should also be paid to whether the tumor has penetrated the capsule and perirenal fat tissue, whether there are enlarged lymph nodes, whether there are cancer thrombi in the renal vein and inferior vena cava, and whether there is liver metastasis.

4. CT scan: CT plays an important role in the diagnosis of renal cancer. It can detect renal cancer that has not caused changes in the renal pelvis and calyx and has no symptoms. It can accurately measure the tumor density and can be performed in outpatient clinics. CT can accurately stage. Some people have calculated its diagnostic accuracy: 91% of invasion of the renal vein, 78% of perirenal spread, 87% of lymph node metastasis, and 96% of involvement of nearby organs. Renal cancer CT examination shows a mass in the renal parenchyma, which can also protrude from the renal parenchyma. The mass is round, quasi-round or lobed, with clear or blurred boundaries. It is a soft tissue mass with uneven density during plain scanning. The CT value is >20Hu, usually between 30 and 50Hu, slightly higher than the normal renal parenchyma, or similar or slightly lower. The internal unevenness is caused by hemorrhage, necrosis or calcification. Sometimes it can be manifested as a cystic CT value, but there are soft tissue nodules on the cyst wall. After intravenous injection of contrast agent, the CT value of normal renal parenchyma reaches about 120Hu, and the CT value of the tumor also increases, but it is significantly lower than the normal renal parenchyma, making the tumor boundary clearer. If the CT value of the mass does not change after enhancement, it may be a cyst. The diagnosis can be confirmed by combining the CT value before and after contrast medium injection as liquid density. In necrotic foci in renal cancer, renal cystadenocarcinoma, and after renal artery embolization, the CT value does not increase after contrast medium injection. Because renal angiomyolipoma contains a large amount of fat, the CT value is often negative and the interior is uneven. After enhancement, the CT value increases, but it still shows fat density. During CT examination, oncocytoma has clear edges and uniform internal density, and the CT value increases significantly after enhancement.

The above is some knowledge about kidney cancer examination that we have prepared for you today. We hope it can be helpful to you. If you have any other needs, you can also consult our online consulting experts. We are always here to answer your questions.

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