Renal pelvis tumors

　　Renal pelvis tumors are formed in this way: the mucosa of the collecting ducts, renal calyces, renal pelvis, ureter, bladder, and urethra originate from the same source during embryonic development and are collectively referred to as 'uroepithelium'. Due to the common transitional epithelium, tumors of the renal pelvis and ureter are considered simultaneously. The transitional epithelium lines the renal calyces and renal pelvis, exposed to many urinary potential carcinogens. The excreted carcinogens may be activated by hydrolytic enzymes in the urine, causing carcinogenic effects in the urinary system and resulting in a higher incidence of bladder tumors than in the upper urinary tract.

　　Most renal pelvis tumors are transitional cell papillary tumors. Tumors can be solitary or multiple. The rich blood supply of the tumor makes it prone to rupture and hemorrhage, leading to hematuria. Tumor cells that detach can be implanted in the ipsilateral ureter or bladder with the urine. The metastatic pathway is often early lymphatic metastasis due to the thin muscularis propria of the renal pelvis wall and rich lymphatic tissue around it, with transitional cell carcinoma being the most common. Papillary transitional cell carcinoma is well differentiated and indistinguishable from normal renal pelvis epithelium. Squamous cell carcinoma is rare, accounting for only 3% to 4%, and adenocarcinoma is very rare. Those located at the renal pelvis ureteral junction may be complicated by hydronephrosis. Renal pelvis tumors can metastasize via lymphatic, hematogenous, and direct spread.

　　The main complications of renal pelvis tumors are that the lesion can spread directly or metastasize hematogenously to the lung, liver, bone, and other organs, causing multi-organ tumors. Hematogenous metastasis is one of the pathways of cancer cell spread, referring to the spread of cancer cells through vascular pathways to tissues or organs outside the cancer tissue, forming metastatic cancer, generally following the direction of blood flow.

　　Renal pelvis tumors are commonly seen in patients aged 40 to 70 years, with a male to female ratio of 2 to 3 to 1. The most common symptom is gross or microscopic hematuria (70% to 95% incidence rate), which is also the earliest symptom. Even small tumors can appear early with hematuria, which is intermittent, painless, and visible to the naked eye. If the tumor causes obstruction of the ureter or the junction of the ureter and renal pelvis, it can lead to sudden pain (8% to 40%), or due to excessive bleeding, form a string-like blood clot that causes renal colic when passing through the ureter. In advanced cases, the tumor grows larger or causes obstruction, leading to hydronephrosis, at which time renal area masses and signs of metastasis may appear, with some patients experiencing pain, secondary infection, and urinary tract stones. 5% to 10% of patients may have symptoms of bladder irritation, and physical examination usually does not show positive findings. Reports indicate that 10% to 20% of patients may have a mass in the lumbar region caused by a tumor or hydronephrosis, most of which are asymptomatic and without signs, and 10% to 15% are found incidentally. Advanced renal pelvis tumors often metastasize to the liver, lung, and bone, while early metastasis can occur to lymph nodes. In advanced stages, symptoms such as anorexia, weight loss, anemia, and cachexia may occur.

　　The prevention of renal pelvis tumors is divided into three levels of prevention, like other malignant tumors, as follows:

　　First-level prevention is the prevention of etiology, with the goal of preventing the occurrence of cancer. Its tasks include studying various causes and risk factors of cancer, taking preventive measures against specific carcinogenic, promoting carcinogenic factors such as chemicals, physics, and biology, and pathogenic conditions inside and outside the body, and taking measures to strengthen environmental protection, appropriate diet, and appropriate physical exercise for healthy organisms to enhance physical and mental health.

　　1. Avoid smoking: Smoking has been clearly identified as a carcinogenic factor known to people, related to 30% of cancers. Tar in cigarettes contains various carcinogenic and promoting carcinogenic substances. Smoking mainly causes cancers of the lung, pharynx, larynx, and esophagus, and can also increase the risk of tumors in many other parts of the body.

　　2. Adjust dietary structure: A reasonable diet has a preventive effect on most cancers, especially in plant-based foods, which contain a variety of anti-cancer components. These components are almost effective in preventing the occurrence of all cancers. Investigations show that colorectal cancer, breast cancer, esophageal cancer, gastric cancer, and lung cancer are most likely to be prevented by changing dietary habits.

　　3. Preventing tumors in different parts caused by occupational and environmental pollution, drugs, and other reasons, such as lung cancer (asbestos), bladder cancer (aniline dyes), leukemia (benzene) and so on are all related to the above factors. Some infectious diseases are also closely related to certain cancers: such as hepatitis B virus and liver cancer, human papillomavirus and cervical cancer. In some countries, the risk of bladder cancer is significantly increased by schistosomiasis. Exposure to some ionizing radiation and a large amount of ultraviolet light, especially sunlight, can also lead to skin cancer. Commonly used carcinogenic drugs include estrogens and androgens, anti-estrogen drug tamoxifen (triphenoxytamoxifen), and estrogen widely used in postmenopausal women is related to endometrial cancer and breast cancer.

　　Two-level prevention or preclinical prevention aims to prevent the development of primary diseases. It includes early detection, early diagnosis, and early treatment of cancer to prevent or slow down the progression of the disease and reverse it to stage 0 as soon as possible.

　　Three-level prevention is clinical (stage) prevention or rehabilitation prevention. Its goal is to prevent the deterioration of the disease and the occurrence of disability. The task is to adopt multidisciplinary comprehensive diagnosis (MDD) and treatment (MDT), correctly select reasonable and optimal treatment plans to extinguish cancer as soon as possible, and strive to promote recovery and rehabilitation, prolong life, improve the quality of life, and even return to society.

　　The various examinations for renal pelvis tumors may have the following characteristics:

　　1. X-ray examination

　　Excretory urography shows irregular filling defects in the renal pelvis and calyces, with uneven density; when hydronephrosis and renal function are poor, the kidneys do not show shadowing; if there is obstruction at the renal calyx-pelvis junction, it is manifested as hydronephrosis of the renal minor calyces. For highly suspected lesions, it is advisable to use low-density contrast agents and take X-ray photographs from different angles multiple times for observation. For cases where the kidneys do not show shadowing, retrograde urography should be used for examination.

　　Retrograde urography is the most important examination method for diagnosing renal pelvis cancer, especially when excretory urography shows poor shadowing. This method can also directly collect urine from the affected side or use saline to flush and collect samples. It can also be used to brush the ureter for histological examination and tumor cytology. Non-ionic contrast agents can be used during retrograde urography, and it should be prevented to bring in air bubbles that may cause misdiagnosis.

　　2. Ultrasound examination

　　It is characterized by central renal sinus echo separation or hypoechoic, and when hydronephrosis is present, there may be solid irregular echo or irregular contour in the renal pelvis. Ultrasound examination is prone to miss small tumors.

　　3. CT examination

　　When intravenous pyelography does not show shadowing, CT scan is of great significance. Plain scan can show soft tissue mass (CT value 20-40Hu) filling the renal pelvis and renal hilum area, with the renal sinus fat shadow narrowing or disappearing, often accompanied by hydronephrosis; the CT value of the mass increases compared to the plain scan, and CT examination is superior to B-ultrasound in tumor staging, and can clearly determine whether there is local infiltration, lymph node metastasis, or thrombus formation in the cavernous vein.

　　4. MRI, MRU

　　The latter provides images of the renal parenchyma and collecting system, fully displaying the tumor, which is of great significance for the diagnosis of patients with obstruction.

　　5. Cystoscopy

　　Blood can be seen from the ureteral orifice on the affected side or bladder tumors or ureteral end tumors often associated with them. Under X-ray guidance, use a special P6 ureteral catheter with a brush to directly brush the renal pelvis lesion tissue for pathological examination, which can improve the diagnostic rate.

　　6. Renal Pelvis Ureteroscopy

　　The renal pelvis scope can be sent into the renal pelvis to directly observe the condition of the lesion and can take a biopsy to clarify the nature of the mass.

　　Specific dietary recommendations for renal pelvis tumor patients should be consulted with a doctor based on symptoms, eat a balanced diet to ensure comprehensive and balanced nutrition. Eat more vegetables and fruits, eat light, quit smoking and drinking, and avoid spicy and刺激性 food.

　　Renal pelvis tumors are primarily treated by surgery, and radiotherapy and chemotherapy are not very effective. The surgical scope is the entire kidney and ureter, otherwise the possibility of tumor occurrence in the ureter reaches 84%.

　　1. Surgical Treatment

　　The classic operation for renal pelvis tumor is to remove the kidney, ureter, and bladder cuff-like resection. The resection of the kidney and the entire ureter also includes the bladder wall within 2cm of the ureteral orifice. The operation should generally be completed in one stage, and for patients with very poor general condition, it can be divided into two stages. However, this operation generally does not perform lymph node dissection because it cannot improve survival rates. The necessity of total ureteral resection is due to the fact that transitional cell carcinoma often seeds on the same side of the lower urinary tract, causing 20% of patients to develop tumors at the residual ureteral end. If the patient has a solitary kidney, renal dysfunction, or bilateral lesions, local excision can be performed, that is, local excision of renal pelvis lesions, with or without partial nephrectomy.

　　2. Endoscopic Treatment

　　Small tumors with good cell differentiation and no infiltration confirmed by biopsy can be treated conservatively by local excision or percutaneous nephroscope, ureteroscope electrocautery, and incision. Regular cystoscopy after surgery and bladder perfusion with anticancer drugs are recommended to prevent recurrence of the tumor.