Wilms' tumor

　　The occurrence of Wilms' tumor may be related to developmental abnormalities and many chemical and biological factors. Wilms' tumor may be the result of abnormal proliferation caused by the metanephric bud not differentiating into renal tubules and glomeruli.

　　From an embryological point of view, the persistent metanephric bud does not differentiate into glomeruli and renal tubules and shows abnormal proliferation, developing into Wilms' tumor. The tumor can appear in the form of heredity or non-heredity. If it is of hereditary form, the tumor occurs earlier and is more likely to be bilateral and multicentric. All bilateral Wilms' tumors and 15% to 20% of unilateral lesions are related to heredity.

　　The main complications of Wilms' tumor are rapid tumor growth, which can directly spread or metastasize hematogenously to the lung, liver, retroperitoneum, mediastinum, pleura, adrenal glands, bone, and other organs, causing multiple organ tumors. Polycythemia is rare and may be related to the tumor producing erythropoietin.

　　Wilms' tumor has different clinical manifestations, with an abdominal mass being the most common symptom. About 75% of patients present with an abdominal mass or abdominal distension.

　　1. Abdominal mass

　　Many children with Wilms' tumor have no symptoms in the early stages. The characteristic of the disease is a large abdominal mass in frail infants and young children, often discovered accidentally by parents or doctors. The mass grows rapidly. The size of Wilms' tumor varies greatly, with small tumors having a diameter of only a few centimeters, and large tumors can be extremely large, filling the abdominal cavity and affecting respiration, causing dyspnea. The tumor is easily palpable, firm, smooth, and has poor mobility. Occasionally, there may also be a nodular sensation. The firmness and immobility can be distinguished from hydronephrosis or renal cysts. Other physical examination findings include aniridia, unilateral swelling, etc. There are often hypertension and fever, and renin activity and erythropoietin in the blood may also be higher than normal.

　　2. Hematuria

　　Since the tumor rarely invades the renal pelvis, hematuria is not prominent. About 50% of children have abdominal pain as the initial symptom, while hematuria and fever account for 20% to 25%. General symptoms such as fatigue, discomfort, and weight loss are mostly late manifestations. One-third of children are diagnosed at age 2 or under, and two-thirds are diagnosed by age 4.

　　3. Hypertension

　　Hypertension appears secondary to increased renin production due to tumor formation or compression of the renal artery by the mass, with an incidence rate of 30% to 65%. In the late stage, 10% to 25% may develop hematuria, with poor prognosis. After the tumor is surgically removed, blood pressure can return to normal.

　　4. Low back pain or abdominal pain

　　About 30% of cases have low back pain or abdominal pain, which may be due to tumor hemorrhage. In addition, renal embryonal tumor can manifest as polycythemia or Cushing's syndrome. The disease is mostly unilateral, with 10% to 15% being bilateral, and extrarenal renal embryonal tumor is rare. Before 1990, only 10 cases were reported worldwide.

　　5. Congenital iris aplasia

　　The incidence of this disease is about 1.4%, also known as aniridia-wilms tumor syndrome.

　　6. Other

　　The digestive tract may appear symptoms of obstruction such as nausea, vomiting, abdominal distension, or lower limb edema, ascites, and varicocele of the spermatic cord, which are caused by tumor compression of the inferior vena cava.

　　Early detection and early treatment are the key to preventing Wilms' tumor. The specific measures are as follows:

　　1. Develop good living habits, quit smoking, and limit alcohol consumption. The World Health Organization predicts that if people stop smoking, the world's cancer rate will decrease by 1/3 in 5 years; secondly, do not drink heavily. Cigarettes and alcohol are highly acidic substances, and those who smoke and drink for a long time are prone to develop an acidic体质.

　　2. Do not eat too much salty and spicy food, overheated, cold, expired, and deteriorated food; the elderly, the weak, or those with certain genetic predisposition to diseases should eat some cancer-preventive foods and alkaline foods with high alkaline content, maintaining a good mental state.

　　3. Maintain a good mental state to cope with stress, combine work and rest, and do not overwork. It can be seen that stress is an important trigger for cancer. Traditional Chinese medicine believes that stress leads to overwork and physical weakness, thus causing a decrease in immune function, endocrine disorders, and internal metabolic disorders, leading to the deposition of acidic substances in the body; stress can also lead to mental tension, causing qi stasis and blood stasis, internal fire, and other symptoms.

　　4. Strengthen physical exercise, enhance physical fitness, and exercise more in the sun. Sweating can help expel acidic substances from the body, avoiding the formation of an acidic体质.

　　5. Live a regular life, and those with irregular lifestyles, such as staying up all night to sing karaoke, play Mahjong, not returning home at night, and irregular living, will worsen the acidification of the body, making it easy to develop cancer. It is advisable to develop good living habits to maintain an alkaline体质 and keep various cancer diseases away from oneself.

　　The various examination items for Wilms' tumor have the following characteristics:
　　1. Blood Examination: Renal function is normal, plasma protein is reduced, and the erythrocyte sedimentation rate is generally increased by 15-90mm/h, with a more significant increase in the sedimentation rate in children with very large advanced tumors, which is considered an indicator of poor prognosis. The blood routine generally shows mild anemia, with hemoglobin below normal, but there are also a few cases with an increase in red blood cells, which may be related to an increase in erythropoietin.
　　2. Chromosome Examination: In patients without the iris-rhabdomyosarcoma syndrome, there is a deletion in the short arm of chromosome 11.
　　3. Urine Microscopic Examination: Many have hematuria and proteinuria, but cancer cells cannot be found in the urine.
　　4. Bone Marrow Biopsy: Difficult to distinguish from neuroblastoma.
　　5. Urological X-ray Film: The outline of the kidney disappears, and clear soft tissue mass shadows can be seen, with scattered fine punctate calcification in a few cases.
　　6. Urological Imaging: Includes renal arteriography and venography. Renal arteriography shows that the renal blood vessels are displaced or straightened, with tumor blood vessels present, early enhancement of the renal veins, uneven distribution of contrast agent, thickening of the renal veins, and tumor thrombus obstruction. This examination finds that 2/3 of the children have compression, displacement, elongation, deformation, or destruction of the affected renal pelvis and calyces; 1/3 of the children have no imaging of the affected kidney due to compression of the affected kidney, filling of the renal pelvis with tumor, or renal vascular thrombosis, or only a small amount of contrast agent enters the renal pelvis. When the tumor is large, the affected ureter moves towards the midline.
　　7. Ultrasound examination: Ultrasound examination is very sensitive in distinguishing between cystic and solid masses, and can provide diagnostic clues for Wilms' tumors that are mixed cystic and solid.
　　8. CT scan: In addition to showing large renal masses, due to the frequent occurrence of hemorrhage, necrosis, and cystic changes within the tumor, the mass is often heterogeneous, and even forms lesions mainly composed of large cystic masses. The cyst wall is thick and irregular, and calcification can occur in 15% of cases. CT scan is the most effective method for identifying solid or cystic lesions and can detect other organ lesions, exclude involvement of the contralateral kidney, and differentiate between renal pelvis hydrops, renal cystic diseases, adrenal tumors, and hematomas. The most common site of metastasis for Wilms' tumor is the lung, and chest X-rays and lung CT scans can be used to exclude metastasis. Other examinations can be determined according to clinical needs, such as bone scanning and liver scanning or bone marrow examination.
　　9. Puncture biopsy: The tumor originates from embryonic renal tissue and is a malignant mixed tumor composed of epithelial and stromal tissue. The tumor tissue includes glands, nerves, muscles, cartilage, fat, etc. The cross-section is grayish yellow, and can have cystic changes, patchy hemorrhage, and calcification. There is no obvious boundary with normal renal tissue. The tumor destroys normal renal tissue, causing deformation of the renal pelvis and calyces, and is rarely invasive into the renal pelvis. The metastatic pathways are similar to those of renal cell carcinoma. Bilateral Wilms' tumors account for 5% to 10% of cases. The histopathological examination shows that the tumor size varies, with a thin and brittle pseudocapsule, a cross-section resembling fish meat, pale yellow or gray, with necrosis, hemorrhage, and scattered pseudocysts containing clear or bloody fluid.
　　When a child is suspected of having a tumor mass in the lumbar region, puncture biopsy should be avoided to prevent tumor spread, and surgical exploration is still necessary.

　　For patients with Wilms' tumor, a light diet is recommended, and the following therapeutic diet recipes can be adopted:

　　Ingredients: Carrot 250 grams, water chestnut 250 grams, bamboo sugar 1 piece.

　　Preparation method: Put all the ingredients in a pot, add an appropriate amount of water, boil, and then simmer over low heat for 1 hour.

　　It is worth noting that it can nourish yin, generate fluid, and relieve thirst, and is suitable for those with excessive heat and fluid damage after radiotherapy, swelling and pain in the throat, and dry mouth and tongue. However, those with deficiency of the spleen and stomach, and excessive phlegm and dampness should avoid it.

　　The treatment principles for Wilms' tumor involve various methods such as surgery, radiotherapy, and chemotherapy, which can cure the majority of children, even those with metastases, and achieve good effects. Since Wilms' tumor is sensitive to radiotherapy and chemotherapy, the combination of surgery with radiotherapy and chemotherapy can significantly improve the survival rate after surgery. For larger tumors, preoperative radiotherapy can reduce the tumor size, facilitating surgery, and vincristine can be used for preoperative preparation. Comprehensive treatment of Wilms' tumor for 2 years has a survival rate of 60% to 94%, and no recurrence within 2 to 3 years is considered cured. Bilateral Wilms' tumors can be treated with bilateral tumor resection, supplemented by radiotherapy and chemotherapy. The prognosis for adult Wilms' tumors is poorer, and the chemotherapy methods are similar to those for children.

　　One, Surgical Treatment

　　1. Early nephrectomy is performed through the abdominal route, and the Chevron incision is a good method for removing the kidney. The abdomen needs to be completely exposed, and special attention should be paid to the affected kidney, the opposite kidney, local areas, and paraaortic lymph nodes. The uninvolved kidney needs to be carefully palpated and explored, and the renal fascia needs to be incised to observe for metastatic foci. If there are metastatic foci, they should be removed or a partial nephrectomy should be performed. Before ligating the renal pedicle, the renal vein needs to be palpated to exclude the presence of tumor thrombi. In addition, avoid causing tumor rupture during the decompression. Tumor dissemination can be prevented by total abdominal treatment to prevent local recurrence in the abdomen. A total resection of the affected kidney, renal fascia, ipsilateral adrenal gland, and local lymph nodes is performed.

　　2. If the tumor is adherent to adjacent organs such as the spleen, tail of the pancreas, or lumbar muscle, it can be removed together with the tumor. If the tumor invades important organs such as the duodenum, pancreas, or mesenteric root, then surgery can only be determined after biopsy.

　　Two, Radiotherapy

　　Wilms' tumor is a radioresponsive tumor, and radiotherapy added after surgery can improve the efficacy, but it is rarely done before surgery.

　　Three, Chemotherapy

　　Chemotherapy has a significant effect on improving the survival rate of Wilms' tumor. Actinomycin D and Vincristine are both effective drugs. Chemotherapy can reduce the size of the tumor, reduce lung metastasis, and improve survival rate. The most sensitive drugs are Vincristine and Actinomycin D, and the combined effect of the two drugs is better. Doxorubicin (Adriamycin) and Cyclophosphamide can also be used. The dose of Actinomycin D is 15μg/(kg·d), for a total of 5 days, and the ideal dose can be 1.2mg/m2 every 3 weeks. Repeat at the 6th week and 3 months. After that, repeat every 3 months until the 15th month. Side effects include nausea, vomiting, diarrhea, stomatitis, alopecia, and bone marrow suppression.

　　1. Vincristine: 1.5mg/m2, once a week, for a total of 8 to 10 times, and then repeated before and after the Actinomycin D course for 1 week. Toxic reactions such as peripheral nerve damage, disappearance of deep reflexes of tendons, alopecia, and bone marrow suppression of red blood cell production may occur.

　　2. Cyclophosphamide: 10mg/(kg·d), for a total of 3 days, repeated once every 6 weeks.

　　3. Doxorubicin (Adriamycin): 20mg/m2, once a day, for a total of 3 days, repeated every 3 months alternately with Actinomycin D. In addition to having similar side effects and toxic effects as Actinomycin D, it also has toxic effects on the heart.

　　Four, Treatment of Metastatic Foci

　　1. Local radiation therapy of 12Gy for lung metastasis and 30Gy for liver metastasis, for 3 to 4 weeks, and combined chemotherapy with three drugs is required. Bilateral renal embryonal tumors can occur simultaneously or sequentially, but it is generally not recommended to perform renal transplantation after bilateral nephrectomy, as the prognosis is not better than simple tumor resection combined with radiotherapy and chemotherapy.

　　2. Before treatment, a comprehensive understanding of the specificity and prognostic factors of the tumor is necessary. Formulate an appropriate treatment plan based on the specific case to improve the efficacy of treatment. It is also important to prevent unnecessary and harmful over-treatment during the treatment process. Regular follow-up is essential after the main treatment is completed.

　　3. The comprehensive therapy of surgery combined with chemotherapy and radiotherapy has been recognized as a treatment method. However, how to combine and apply the dosage and course of treatment to achieve the goal of minimizing harm and maximizing efficacy is worthy of in-depth study.

　　4. Nephrectomy is the main treatment method, and there is often a small amount of blood loss during the operation. For large tumors, especially those involving the inferior vena cava, there is a risk of massive bleeding. Therefore, preoperative preparation should include central venous catheter insertion and monitoring, and blood volume can be rapidly replenished if necessary. Radial artery catheter insertion and monitoring can allow for timely blood gas analysis, and a catheter should be placed during the operation and urine output monitored postoperatively.

　　5. The tumor is fragile and prone to rupture, so the abdominal incision must have a wide exposure to facilitate the exposure of the renal vein and exploration of other tumor lesions. The best approach is a transverse incision from the axillary front of the 12th rib to the opposite edge. When resecting a large tumor, it may be necessary to add a chest extension incision to make the surgery easier and safer. A thorough exploration of the abdominal cavity is required, which may involve lymph node and/or liver metastasis. Biopsy should be performed on suspicious lymph nodes, and metal clips should be used for marking. The opposite kidney should be carefully inspected and palpated.

　　6. The traditional requirement for early ligation of the renal vein during surgery is believed to reduce the risk of pulmonary tumor embolism. However, according to various data, the timing of venous ligation does not affect the prognosis. If the renal vein is ligated before the renal artery, the outflow blockage occurs before the inflow blockage, resulting in congestion and swelling of the tumor, increased fragility, and venous rupture of the perirenal tumor. Therefore, when technically feasible, the artery should be blocked early to reduce the size and fragility of the tumor, making it easier to operate. When the tumor is large, it is impossible to expose the renal vein first; it is necessary to wait for the four sides to be freed and reach the renal hilum from the side. If a thoracoabdominal combined incision is made, it is more convenient.

　　7. When encountering rare cases, large tumors and/or patients with poor conditions, in order to make the tumor shrink before surgery for easy and safe resection, a course of vinblastine or radiotherapy or renal artery embolization can be applied. However, before the preoperative treatment plan is used, the survival rate is not improved, and there are the following disadvantages of preoperative treatment: low-dose chemotherapy can also destroy the tissue structure of the tumor, so it is not possible to stage, resulting in inappropriate treatment plans; misdiagnosis can occur. In some cases of abdominal masses, laparotomy proves that it is not Wilms' tumor; infants with stage I tumors receive inappropriate preoperative treatment.