What are the methods for early diagnosis of kidney cancer

Kidney cancer patients often have dull or dull abdominal pain, which is a common symptom in the early stage. It is usually more obvious in the late stage. In the early stage, the pain can be relieved by itself and is not easy to be discovered. This is why many patients delay the treatment of the disease. Therefore, if you have some symptoms, such as low back pain, fatigue, weight loss, abdominal distension, indigestion, nausea, vomiting, unexplained fever and edema, you should seek medical attention in time.

So, what are the most accurate tests for kidney cancer?

X-ray: Plain X-rays and urography are of little value in diagnosing renal cancer, especially plain X-rays, which have limited effect.

(1) Plain film: Larger renal cancers may show local protrusion of the kidney outline, and the outer edge of the kidney may be nodular. About 5-10% of renal cancers may show calcification, which is usually of low density and mostly appears as fine dots, occasionally in the shape of an arc.

(2) Intravenous urography: The findings of urography depend on the size and location of the renal tumor and the degree of invasion of the collecting system. When the tumor is small and limited to the parenchyma, urography may show no abnormal changes. As the lesion develops, the tumor will first push and compress the collecting system, causing deformation, stenosis, elongation, truncation, occlusion or displacement of the renal pelvis and calyx. When the tumor just begins to invade the collecting system, the contours of the renal pelvis and calyx may become irregular and rough. When the tumor grows into the renal pelvis and calyx, filling defects may occur. Tumors with diffuse infiltrative growth may present polycystic kidney-like changes, with irregular shapes of the renal pelvis and calyx, and may also cause loss of function of the affected kidney. They will not be visualized during imaging, and only irregular enlargement of the renal shadow will be shown. Huge tumors may cause deviation of the renal axis and may also compress and push the ureter. When the tumor protrudes toward the renal hilum or metastasizes to the renal hilar lymph nodes, the normally concave renal hilar shadow disappears.

(3) Retrograde upper urinary tract angiography: This examination is not very helpful in the diagnosis of renal cancer, but it can be used to differentiate kidneys that do not show up in intravenous urography from other upper urinary tract lesions.

Ultrasound: B-ultrasound examination is simple and easy to perform, and does not cause pain or trauma to the examinee. It has now become one of the main items for regular health checkups in many units. More and more asymptomatic renal cancers are discovered in this way. B-ultrasound has a high sensitivity in detecting kidney tumors and can be used as the preferred examination method. The mass-like echoes in the renal parenchyma are a direct sign of ultrasound diagnosis of renal cancer. However, it should also be noted that B-ultrasound images of renal cancer are non-specific, especially for tumors with a diameter of <2cm or atypical sonographic manifestations. Diagnosis is somewhat difficult and requires close combination with clinical and other examination results for comprehensive analysis and judgment. On B-ultrasound images, typical renal cancer may have the following manifestations:

(1) Changes in kidney contour: When the tumor is small, the kidney contour may not change significantly. Larger tumors protrude from the kidney surface, causing the kidney contour to increase in localized size and become uneven. The kidney shape loses its normal appearance. The boundary between the tumor and the surrounding tissue is relatively clear. However, when advanced renal cancer infiltrates the surrounding tissue extensively, the boundary is often unclear.

(2) Abnormal echo of renal parenchyma: Abnormal echo masses appear in the renal parenchyma, which are round or oval in shape, with clear boundaries and a sense of sphere. The internal echo varies. Most medium-sized tumors are low-echoic, and only a few are mixed echoes or equal echoes of varying strengths. When there is bleeding, necrosis or liquefaction inside a larger tumor, an irregularly edged anechoic area will appear locally. If there is calcification, it will appear as a point or block of strong echoes with acoustic shadows. Smaller renal cancers sometimes appear as high-echo masses.

(3) The echo of the renal sinus is compressed and deformed: When the tumor grows inward and compresses or invades the renal sinus, the renal sinus may become concave, displaced, interrupted, or even unclear. In a few cases, the renal pelvis and calyx may expand and accumulate water.

(4) Abnormal changes in blood vessels around the kidney: In the late stage of renal cancer, when the cancerous tissue invades or metastasizes through the bloodstream to the renal vein and lower limb vein, the ipsilateral renal vein or inferior vena cava will widen and become blocked, with irregular low- and medium-level dot-like or mass-like echoes. (5) Signs of renal cancer metastasis: abnormal mass-like low echoes in organs such as the renal hilum and retroperitoneal enlarged lymph nodes, liver, adrenal glands, and contralateral kidney.

(6) Differentiation from normal kidney variation: The hypertrophic renal column appears as a circular or elliptical low-echo area on the longitudinal section of the kidney, which is often seen in the middle and upper poles of the kidney, and resembles the echo of a renal tumor. However, careful observation reveals that the renal column is clearly demarcated from the renal sinus, and the interior is evenly distributed with tiny dot-like low-echoes. The cross-section shows that the low-echo of the renal column is continuous with the renal cortex, with no clear boundary between them. The cross-section of renal cancer has a clear boundary with the renal cortex and a distinct spherical feel. Some kidneys are abnormally lobed, causing the renal outline to bulge locally, which is often seen on the outer side of the middle and lower poles of the left kidney. In severe cases, the renal fusion is incomplete. The bulge is relatively large, but there is no boundary with the renal cortical echo, and there is no tumor configuration.

(7) Color Doppler ultrasound: It is mainly used to understand the extent of venous invasion. According to a report by Habboub et al., in the examination of 46 cases of renal cancer with venous thrombus confirmed by surgery, the accuracy of diagnosis of thrombus in the renal vein and inferior vena cava was 93%, the sensitivity was 81%, and the specificity was 98%.

Warm reminder: Paying attention to a balanced diet is the best way for kidney cancer patients to maintain a normal weight. The diet should be balanced, diversified, not partial to one food, not taboo, and a combination of meat and vegetables, coarse and fine. Family members should pay attention when preparing meals for patients, use steaming, boiling, and stewing more often when cooking, and try to eat less fried food.