1.What is renal occupancy? What diseases are included? Renal occupancy is an abbreviation about renal occupying lesions, a term used in imaging examinations (ultrasound, CT, MRI, etc.), which is not a very standardized term strictly speaking, including benign and malignant lesions. Benign lesions include simple renal cysts, polycystic kidneys, renal abscesses, parasitic masses, hematomas and some benign tumors, such as malignant tumors (vascular smooth muscle lipoma), inflammatory pseudotumor, pheochromocytoma, paraglobular cell tumor, etc. Malignant lesions are mainly malignant tumors, including renal cell carcinoma, cystic kidney cancer, epithelial tumor of renal pelvis and calyx, nephroblastoma and so on. 2.Does renal cysts matter? Renal cyst is a general term for cystic masses of different sizes in the kidney that are not connected to the outside world. Common renal cysts can be divided into adult-type polycystic kidney, simple renal cyst (single and multiple) and acquired renal cyst. There are more etiologies, heredity, congenital dysplasia, genetic mutation, infection, exposure to toxic and harmful substances, etc. are possible. Diagnosis: Ultrasound, CT and so on can be clear, usually there is no clinical symptom but found by physical examination, a few will have abdominal pain on the side of the lesion, low back pain, etc. If there is acute bleeding in the cyst, there will be severe pain in the back. Treatment: If the cyst is small, it can be observed clinically and does not need special treatment. If the cyst is >4cm in diameter, it usually needs to be treated by surgical decompression of the apex (laparoscopic minimally invasive surgery, open surgery, etc.); or cyst puncture and fluid aspiration and sclerotherapy (less frequently used). 3.Are all kidney tumors malignant? Not all kidney tumors are malignant, but malignant ones are in the majority. Benign tumors include misshapen tumor (angiosarcoma), inflammatory pseudotumor, eosinophilic tumor, paraglomerular cell tumor, etc. Malignant tumors include renal cell carcinoma, cystic kidney cancer, renal pelvis (calyx) cancer, nephroblastoma, sarcoma, fibrosarcoma, liposarcoma, smooth muscle sarcoma and other malignant tumors metastasized to the kidney. Renal cell carcinoma in adults accounts for about 90% or more of malignant tumors of renal origin. Renoblastoma is a pediatric tumor. 4.What are the symptoms of kidney cancer? What are the main causes? Typical clinical manifestations of kidney cancer include: hematuria, pain, lumbar mass and extra-renal manifestations (fever, hypertension, varicocele, rapid hematocrit, erythrocytosis, abnormal liver function, elevated carcinoembryonic antigen of hypercalcemia, etc.). With the enhancement of people’s health awareness, more and more early kidney cancers (asymptomatic) are detected through physical examination (ultrasound, CT, MRI, etc.), while those with typical symptoms are becoming less and less. The treatment effect of early stage kidney cancer is relatively better. 5.Do I have to remove the kidney if I have kidney cancer? With the progress of medical technology and clinicians’ continuous exploration and research, some kidney cancers can now be operated with preserved kidney units. In other words, the tumor is completely removed while the normal kidney tissue is preserved to protect the kidney function to the maximum extent. As long as the patient selection is appropriate and the surgery is performed properly, the efficacy of kidney unit preservation surgery is completely comparable to radical nephrectomy. 6.What kind of kidney cancer can undergo renal unit preservation surgery? Cases of kidney unit preserving surgery must be strictly screened, and the indications should never be relaxed in order to pursue kidney unit preserving surgery. The indications for routine kidney unit preservation surgery include: ① absolute indications: kidney cancer occurs in anatomically or functionally isolated kidney, such as congenital isolated kidney, contralateral renal insufficiency or non-functional, and bilateral kidney cancer. ② Relative indications:Patients with certain benign diseases in the kidney contralateral to the kidney cancer, such as kidney stones, chronic pyelonephritis or other diseases that may lead to deterioration of kidney function (such as hypertension, diabetes, renal artery stenosis, etc.). Surgery to preserve the renal unit is particularly suitable for tumors located at the upper and lower poles or margins. The extent of parenchymal resection should be 0.5-1.0 cm from the edge of the tumor, and tumor diameter <4 cm is most appropriate, which can be relaxed to <7 cm in some cases. 7. Will preserved renal unit surgery cause unclean tumor cutting? Will preserved renal unit surgery make tumor recurrence more likely to occur? Preserved renal unit surgery must be strictly controlled by the surgical indications and considered by experienced surgeons in a comprehensive manner, and the surgery should be performed in accordance with the standard preserved renal unit surgery, which will not cause residual tumor or higher recurrence rate than that after radical nephrectomy.