Epidemiology and Etiology
Renal cell carcinoma is a malignant tumor originating from the urinary tubular epithelial system of the renal parenchyma.
The etiology of kidney cancer is not known. A small number of kidney cancers are related to genetic factors and are called hereditary kidney cancer or familial kidney cancer. Kidney cancer caused by non-genetic factors is called sporadic kidney cancer.
I. Gross: There is often a pseudo-envelope separating it from the surrounding kidney tissue. Hereditary kidney cancer, on the other hand, often presents as bilateral, multiple tumors.
Classification: The WHO 1997 classification criteria for renal parenchymal epithelial tumors based on the origin of tumor cells and genetic alterations are recommended
Clear cell carcinoma, papillary renal cell carcinoma or chromophobe carcinoma, suspicious cell carcinoma, collecting duct carcinoma and unclassified renal cell carcinoma.
Histological grading: The grading standard of classifying kidney cancer into highly differentiated, moderately differentiated and poorly differentiated (end-differentiated) is recommended.
IV. Staging: The TNM staging and clinical staging of AJCC in 2002 are recommended.
Clinical manifestations
The classic “triad of kidney cancer”, including hematuria, back pain and abdominal mass, is often diagnosed at an advanced stage. The detection rate of asymptomatic kidney cancer is increasing year by year.
Paraneoplastic syndrome: manifests as hypertension, anemia, weight loss, cachexia, fever, erythrocytosis, abnormal liver function, hypercalcemia, hyperglycemia, increased sedimentation, neuromuscular lesions, amyloidosis, overflow, abnormal coagulation mechanism and other changes.
Metastatic kidney cancer: symptoms such as bone pain, fracture, cough and hemoptysis due to tumor metastasis may be seen.
Diagnosis
The clinical diagnosis of kidney cancer mainly relies on imaging examination, while the confirmation of diagnosis relies on pathological examination.
Abdominal CT scan and enhanced scan and chest X-ray are the main basis for preoperative clinical staging.
Puncture biopsy and renal angiography have limited diagnostic value for kidney cancer and are not recommended as routine examination items.
Treatment
I. Treatment of limited renal cancer
Surgery is the preferred treatment for limited renal cancer.
1.Radical nephrectomy: It is the only method that is recognized as a possible cure for kidney cancer. When radical nephrectomy is performed, the addition of regional or expanded lymph node dissection is not recommended.
The scope of classical radical nephrectomy includes: perinephric fascia, perinephric fat, affected kidney, ipsilateral adrenal gland, hilar lymph nodes and ureter above the iliac vessel division.
Modern view: if the clinical stage is I or II, the tumor is located in the middle or lower part of the kidney, the tumor is <8cm, and the preoperative CT shows normal adrenal gland, radical nephrectomy with preservation of ipsilateral adrenal gland can be chosen.
2.Nephron sparing surgery (NSS).
The extent of NSS renal parenchymal resection should be 0.5-1.0 cm from the tumor margin.
Indications for NSS: isolated kidney cancer, contralateral renal insufficiency or non-functional, bilateral kidney cancer, etc.
Relative indications for NSS: patients with certain benign diseases in the contralateral kidney of kidney cancer, such as kidney stone, chronic pyelonephritis or other diseases that may lead to deterioration of kidney function (such as hypertension, diabetes, narrow renal artery, etc.).
The indications and relative indications for NSS are not specifically limited to tumor size.
The indications for NSS can be selected: clinical stage T1a (tumor ≤4cm), tumor located in the periphery of the kidney, single asymptomatic kidney cancer, and normal contralateral kidney function can choose to perform NSS.
3.Laparoscopic surgery.
Surgical modality: including laparoscopic radical nephrectomy and laparoscopic partial nephrectomy.
Surgical route: divided into transabdominal, retroperitoneal and hand-assisted laparoscopy.
Laparoscopic surgery is suitable for limited renal cancer with tumor confined to the renal peritoneum, without surrounding tissue invasion and without lymphatic metastasis and venous tumor thrombosis.
4.Minimally invasive treatment: radiofrequency ablation, high-intensity focused ultrasound and cryoablation for kidney cancer are in clinical research stage, and are not recommended as the first choice of surgical treatment.
5.Renal artery embolization.
Preoperative renal artery embolization may be beneficial to reduce intraoperative bleeding and increase the chance of radical surgery, but there is no evidence-based medical evidence.
Renal artery embolization can cause complications such as puncture site hematoma, post-embolization infarction syndrome, and acute pulmonary infarction. It is not recommended for routine preoperative application.
6. Postoperative adjuvant therapy.
The 5-year survival rate of pTla renal cancer surgical treatment is up to 90% or more, and postoperative adjuvant therapy is not recommended.
Metastasis occurs in about 20%-30% of patients within 1-2 years after surgery for pTlb-pT2 stage kidney cancer. Adjuvant radiotherapy and chemotherapy are not recommended to be applied routinely after surgery.
Treatment of locally progressive kidney cancer
The preferred treatment for locally progressive kidney cancer is radical nephrectomy. For patients with residual tumor after surgery, immunotherapy or difluorodeoxycytidine (trade name gemcitabine, keyselect) based chemotherapy or (and) radiotherapy is recommended [2].
1. lymph node dissection.
For patients with stage III or IV renal cancer with enlarged lymph nodes, radical nephrectomy + enlarged lymph node dissection is recommended for patients with easier removal of enlarged lymph nodes.
2.Surgical treatment of inferior vena cava tumor embolism.
Most scholars believe that TNM stage, length of tumor embolus and whether the tumor embolus infiltrates the vena cava wall have a direct relationship with prognosis.
It is recommended that patients with clinical stage T3bN0M0 and good behavioral status should undergo inferior vena cava tumor embolism removal. This procedure is not recommended for patients with CT or MRI scans suggesting invasion of the inferior vena cava wall or with lymph node metastases or distant metastases.
There is no uniform classification of venous aneurysm emboli. The Mayo Clinic’s five-level classification is recommended.
Grade 0: Aneurysmal emboli confined to the renal vein;
Grade I: Aneurysm located in the inferior vena cava with the tip of the aneurysm ≤ 2 cm from the opening of the renal vein;
Grade II: the tumor is located in the inferior vena cava below the level of the hepatic vein, and the tip of the tumor is >2 cm from the opening of the renal vein;
Grade III: the tumor is located in the inferior vena cava within the liver, below the diaphragm;
Grade IV: the tumor embolus is located in the inferior vena cava above the diaphragm.
3.Postoperative adjuvant therapy.
There is no standard adjuvant treatment protocol, and studies related to adjuvant IFN-α or/and IL-2 therapy are ongoing and inconclusive. Autologous tumor vaccine.
Kidney cancer is a tumor that is not sensitive to radiation.
III. Treatment of metastatic kidney cancer (clinical stage IV)
Adopt comprehensive treatment mainly based on internal medicine.
1.Surgical treatment.
Removal of the primary foci of kidney can improve the efficacy of IFN-α or (and) IL-2 in the treatment of metastatic kidney cancer.
For patients with isolated metastases after radical nephrectomy and patients with renal cancer with isolated metastases, good behavioral status and low risk factors, surgical treatment can be chosen.
For patients with severe symptoms such as hematuria and pain caused by renal tumor, palliative nephrectomy and renal artery embolization can be chosen to relieve symptoms and improve survival quality.
2.Medical treatment.
The results of randomized controlled study cannot prove that LAK cells, TIL cells, and IFN-γ are effective in the treatment of metastatic renal cancer.
Currently IFN-α or (and) IL-2 is the first-line treatment option for metastatic renal cancer treatment, with an efficiency of about 15%.
The efficacy of commonly used chemotherapeutic agents (either alone or in combination) in metastatic kidney cancer cannot yet be determined.
It is recommended to use the new efficacy evaluation criteria for solid tumors (RECIST) to evaluate the efficacy of immunotherapy or chemotherapy for kidney cancer.
3.Radiotherapy: For patients with local tumor bed recurrence, regional or distant lymph node metastasis, bone or lung metastasis, palliative radiotherapy can achieve pain relief and improve survival quality.
Prognosis influencing factors
The most important factor affecting the prognosis of kidney cancer is the pathological stage, followed by the histological type.
The prognosis of papillary renal cell carcinoma and suspicious cell carcinoma is better than that of clear cell carcinoma; the prognosis of collecting duct carcinoma is worse than that of clear cell carcinoma.
Diagnosis and treatment of hereditary kidney cancer
The defined hereditary renal cancer includes.
①VHL syndrome.
② hereditary papillary renal carcinoma.
③ hereditary smooth muscle tumor disease kidney cancer, ③ hereditary smooth muscle tumor disease kidney cancer
④BHD (Birt-Hogg-Dube) syndrome.
I. Diagnostic points of hereditary renal cancer.
①Middle-aged and young people are the most affected, with/without family history;
②The renal tumors are often bilateral and multiple, and the imaging has the characteristics of renal cancer.
③ Other manifestations of the above syndromes, such as VHL syndrome may be combined with changes of central nervous system and retinal angioblastoma, pancreatic cysts or tumors, adrenal pheochromocytoma, epididymal papillary cystadenoma, renal cysts, etc.
④Testing confirms the corresponding chromosomal and genetic abnormalities.
II. Treatment of hereditary renal cancer
Treatment principle of renal cancer with VHL syndrome: observe and wait for renal tumor diameter <3cm, and consider surgery when the maximum diameter of tumor is ≥3cm, with NSS as the first choice, including tumor enucleation.
Follow up
The first follow-up can be performed 4~6 weeks after surgery, mainly to assess renal function, recovery status after blood loss and whether there are any surgical complications.
Routine follow-up examination includes
①History questioning.
②Physical examination.
③ Routine blood and blood biochemical examination: liver and kidney function as well as blood biochemical indicators of abnormal preoperative examination, recurrent or persistent alkaline phosphatase abnormalities usually suggest distant metastasis or residual tumor. It may also be a manifestation of liver metastasis or paraneoplastic syndrome.
④ Chest X-ray (frontal and lateral). Patients with abnormal findings on chest X-ray examination are recommended to undergo CT scan examination of the chest.
⑤ Abdominal ultrasound examination. Patients with abnormalities found in abdominal ultrasound examination, NSS and post-surgical patients with T3-T4 stage kidney cancer need to have abdominal CT scan examination, which can be performed once every 6 months for 2 years, and later depending on the specific situation.
Follow-up time frame for each stage of kidney cancer.
①T1-T2: follow-up once every 3-6 months for 3 years, and then once a year.
②T3-T4: follow-up every 3 months for 2 years, then every 6 months in the third year, and annually thereafter.
③After treatment of VHL syndrome: CT scans of the abdomen and head should be performed once every 6 months. MRI of the central nervous system, urinary catecholamine measurement, ophthalmology and hearing examination should be performed once a year.