Kidney cancer, also known as renal cell carcinoma and renal adenocarcinoma, originates from renal tubular epithelial cells and can occur in any part of the kidney parenchyma, but it is more common in the upper and lower parts, and a few invade the whole kidney; it has equal chance to develop in the left and right kidney, and bilateral lesions account for 1%-2%.
I. Kidney cancer symptoms
Regardless of the size of kidney cancer, about 80% of patients may not have any symptoms in the early stage, and only during the census or physical examination or ultrasound examination for other reasons are they found to have occupying lesions in the kidney or abdominal masses to touch. Some patients with small primary cancer foci in the kidney and no urinary tract or intrarenal symptoms may first show symptoms of distant metastatic cancer. For example, if a patient is found to have a lump under the armpit or abdomen, it is only discovered to be kidney cancer in order to find the primary lesion. Therefore, it is very important to understand the symptoms of kidney cancer in time.
The symptoms of kidney cancer are mainly as follows.
1. abdominal mass.
About 20% of kidney cancer patients have abdominal masses, which are more likely to appear in long and thin body types, located under the rib cage of upper abdomen and can move up and down with breathing movement. What the examiner touches may be the tumor itself or the lower pole of the kidney pushed by the tumor. If the mass is fixed, it means the tumor has invaded the organ structures around the kidney. It is difficult to remove the tumor in such patients and the prognosis is poor.
2. Hematuria.
The kidney is connected with the outside world through urine, so hematuria is one of the most common clinical symptoms of renal cell carcinoma, which is caused by the tumor invading the mucosa of renal mons or renal calyces. About 40-60 patients will have varying degrees of hematuria, which is usually intermittent and painless throughout the whole process, sometimes with streaky blood clots, which is a ureteral tubular pattern. The blood clot can cause renal colic when it blocks the ureter.
3.Pain.
The pain caused by kidney cancer mostly occurs in the lumbar region and is dull in nature, with an incidence of about 20. The cause is not only due to the tumor growth stretching the kidney peritoneum, but also due to the tumor invading the surrounding organs or lumbar muscles, the latter pain is often heavier and longer lasting. The latter kind of pain is often severe and long-lasting. Renal colic can occur when hematuria is serious and causes ureteral obstruction.
4.Extra-renal manifestations.
In addition to being an important metabolic organ, kidney is also an endocrine organ, which can synthesize and secrete prostaglandin E1, 25D dihydroxyvitamin D3, renin and erythropoietin under normal conditions. Kidney cancer can secrete much higher than normal levels of these hormones, and also secrete parathyroid-like factor, hyperglycemia, into chorionic gonadotropin and insulin and other substances, thus causing kidney cancer These symptoms, except hypercalcemia, are difficult to be eliminated by conventional treatment, however, after removal of the primary foci, most of the indicators can be restored to normal.
(1) Fast blood sedimentation: The cause of fast blood sedimentation in kidney cancer patients is not clear, and the incidence is about 50. In a retrospective study conducted by the University of Oslo in Norway on 236 kidney cancer patients, it was found that 70.3 of the patients showed fast hematocrit even 6 years before the diagnosis of kidney cancer, so it is suggested that renal ultrasound should be performed for patients with persistent fast hematocrit to exclude renal tumors.
(2) Fever: It is also more common in patients with renal cancer, with an incidence of about 20. Recent studies have found that 25 of the primary tumors can ectopically secrete interleukin-6, and this ectopic secretion of interleukin-6 may be associated with fever.
(3) Hypertension: About 20 of kidney cancer patients have hypertension, but recent epidemiological investigations have shown that hypertension and drugs used to treat hypertension are associated with the development of bone cancer; therefore, hypertension can be determined to be caused by kidney cancer only when it returns to normal after removal. Excessive renin secretion, intra-tumor arteriovenous fistula, and tumor compression of renal blood vessels may all be the causes of hypertension.
(4) Hypercalcemia: The cause is not very clear, the incidence is about 10. It may be related to the production of a peptide similar to parathyroid hormone-related protein by the tumor. It returns to normal after removal of the tumor and can be re-elevated after tumor metastasis or recurrence. Sometimes hypercalcemia may also be caused by tumor metastasis to bone.
(5) Erythrocytosis: the specific cause is unclear, it may be related to direct secretion of erythropoietin by tumor or ischemia of normal renal tissue caused by tumor compression, which stimulates secretion of erythropoietin.
(6) Abnormal liver function: It is not caused by tumor metastasis to liver, also known as Staufer syndrome, the patient has leukopenia, fever and local necrosis of liver at the same time. Liver function returns to normal after removal of renal tumor, otherwise metastases are likely to be present. In rare cases, biliary stasis jaundice may also be present.
(7) Other: anemia, weight loss, elevated serum alkaline phosphatase, amyloidosis and neuropathy may occur in patients with renal cancer.
5. Varicocele.
Characterized by not disappearing after lying down position, caused by the obstruction of blood return in the spermatic vein due to the aneurysmal thrombus in the renal vein or inferior vena cava.
6.Metastases.
Metastasis often occurs early in kidney cancer and can appear when the primary focus is very small, and the location of metastasis is variable and seen in almost any part of the body. About 20D35 cases of kidney cancer patients had metastasis when they visited the doctor, and about 6D15 patients came to the doctor because of the symptoms of metastatic foci. In addition to common tumor metastasis sites such as lung, liver, brain and bone, kidney cancer often metastasizes to other rare sites, such as in the lumen of the common bile duct, mediastinum, under the thumbnail, vagina, choroid, external ear canal and orbit. Thus, the possibility of metastasis of kidney cancer should be thought of for abnormal objects appearing in any part of the body, especially those of unknown origin.
7. Concomitant cancer.
DiSilverio et al. have reported 17 cases of primary kidney cancer patients with concomitant primary tumors of steroid hormone target organs, including 10 cases of breast cancer, 4 cases of endometrial cancer and 3 cases of ovarian cancer. Although this does not indicate that kidney cancer is hormone-dependent, it somehow suggests that the link between kidney cancer and these tumors is estrogen.
Classification of kidney cancer
1. Common type (clear cell) kidney cancer is the most common type, accounting for 70%~80% of renal cell carcinoma. Microscopically, the tumor cells are large, round or polygonal, with abundant cytoplasm, transparent or granular, and interstitially rich in capillaries and blood sinuses (Figure 11-23). Most cases of this type are sporadic, while a few are familial and associated with VHL syndrome. The occurrence of this type of kidney cancer is related to VHL gene alteration.
2. Papillary carcinoma accounts for 10%-15% of renal cell carcinoma. It includes two types: basophilic cell and eosinophilic cell. The tumor cells are cuboidal or dwarf columnar with papillary arrangement. Sand granules and foam cells are common in the interstitium of the papillary mid-axis, and edema may occur. This type also includes both familial and sporadic. The occurrence of papillary renal carcinoma is not significantly related to VHL. The cytogenetic alterations in sporadic papillary renal carcinoma are mainly trisomy 7, 16 and 17 chromosomes and loss of y chromosome [t(X,1)] in male patients, whereas the alterations in familial papillary renal carcinoma are mainly trisomy 7 chromosomes. The occurrence of familial clear cell carcinoma is associated with mutations in the proto-oncogene MET, located on chromosome 7.
3.Smut cell carcinoma accounts for about 5% of renal cell carcinoma. Under the microscope, the cells are of different sizes, with lightly stained or slightly eosinophilic cytoplasm and relatively dense cytoplasm near the cell membrane, and there is often a hollow halo around the nucleus. This type of tumor may originate from the epithelial cells of collecting ducts and has a better prognosis. Cytogenetic examination often shows multiple chromosomal deletions and severe subdiploidy. The chromosomes where deletions occur include chromosomes 1, 2, 6, 10, 13, 17, or 21.
Types of kidney cancer also include collecting duct carcinoma and renal carcinoma unclassified. The former is less common, accounting for less than 1% of kidney cancers. The latter includes kidney cancer that cannot be classified into the above categories, accounting for about 3% to 5% of renal cell carcinoma.
III. Clinical manifestations
The complaints and clinical manifestations of kidney cancer patients are variable, which can be easily misdiagnosed as other diseases. Since the kidney is hidden and the main connection with the outside world is urine, hematuria is the most common symptom to detect kidney cancer, but the appearance of hematuria is only possible after the tumor invades the renal pelvis, so it is no longer an early symptom. For many years, hematuria, pain and lumps are called the “triad of kidney cancer”. Most patients have one or two symptoms when they visit the doctor, and those with all three symptoms account for about 10%, so it is rarely possible to cure them.
1.Hematuria.
Hematuria is often painless intermittent episodes of hematuria visible to the naked eye throughout the whole process, and the intermittent period is shortened with the development of lesions. When kidney cancer bleeds a lot, it may be accompanied by renal colic, which is often caused by the passage of blood clots through the ureter. The blood clots in hematuria of kidney cancer may be formed in strips due to the passage through the ureter. The degree of hematuria is not related to the size of the kidney cancer. Kidney cancer may sometimes manifest as persistent microscopic hematuria.
2.Lower back pain.
Low back pain is another common symptom of kidney cancer, mostly dull pain, confined to the lumbar region. The pain is often caused by the growth of masses filling up the renal peritoneum, and blood clots passing through the ureter may also cause low back pain as mentioned above. When the tumor invades the surrounding organs and lumbar muscles, the pain is more severe and persistent.
3.Lumps.
Lump is also a common symptom. About 1/3 to 1/4 of kidney cancer patients can find enlarged kidney when they visit the doctor. Since the kidney is hidden, it is difficult to detect the mass until the kidney cancer reaches a large size. Generally, it is already an advanced symptom when a lump is felt in the abdomen.
4.Pain.
Pain is seen in about 50% of cases and is also an advanced symptom. It is a persistent pain in the affected lumbar region caused by the kidney peritoneum or renal pelvis being pulled by the gradually growing tumor, or by the tumor invading and compressing the connective tissue of the posterior abdominal wall, muscles, lumbar vertebrae or lumbar nerves.
5.Systemic manifestations.
(1) Fever: pyrogenic in tumor tissue.
(2) Hypertension: tumor compression of blood vessels, A-V short circuit in the tumor, etc.
(3) Accelerated blood sedimentation.
(4) Anemia: serum iron and intra-serum transferrin ↓, iron enters cancer cells. The incidence is 30~50%.
(5) Erythrocytosis: Hb>155g/L, hematocrit>50%.
(6) Varicocele: cancerous thrombus in the renal vein.
6.Other symptoms.
Unexplained fever, or metastasis when first detected, lung symptoms such as weakness, weight loss, loss of appetite, anemia, cough and coughing up blood. In addition, the effects of renal adenocarcinoma are caused by the endocrine activity of the tumor and include erythrocytosis, hypertension, hypotension, hypercalcemia, and fever syndrome. Although these systemic, toxic and endocrine effects are non-specific, about 30% of patients first have many mixed manifestations. Thus it is a valuable clue that such findings are considered as systemic effects of the tumor.
4.Early symptoms of kidney cancer
(1) Hematuria.
Most of them are sudden hematuria with no pain or any uncomfortable symptom, and they often occur intermittently and can stop by themselves without being noticed. If the first hematuria is taken seriously, early medical treatment can achieve better results.
(2) Low back pain.
It is the result of the tumor enlarging and compressing the peripheral nerves and intramuscular tissues by pulling the kidney peritoneum. Occasionally, it may be blocked by blood clot when discharging through ureter and cause severe colic, which may be mistaken as kidney or ureteral stone and delay the diagnosis and treatment.
(3) Lumbar mass.
When the tumor tissue grows to a large size and the patient is lying on the side, the mass can be felt in the waist or upper abdomen. If the mass is adhered to the surrounding tissues, fixed and not easily pushed, it is mostly in advanced stage.
V. Precautions for prevention of kidney cancer
1. Quit smoking, avoid radiation and use hormones carefully. Strengthen the protection against lead compounds. Reducing the exposure to chemical carcinogenic substances is a measure that cannot be ignored to prevent this disease.
2.Actively carry out cancer prevention propaganda, popularize cancer prevention knowledge, and achieve early diagnosis and early treatment of kidney tumor, which is the key to determine the treatment effect and prognosis of the disease.
3.Cultivate good hygiene habits and do not consume moldy, rotten and pickled food. It is advisable to use light diet and eat fish, eggs and a small amount of lean animal meat appropriately.
4.Strengthen physical exercise to enhance the ability to resist disease.
5.Keep an optimistic outlook on life, stabilize emotions and improve the quality of life.
6.Patients recovering from surgery should be reviewed regularly, once every one to three months, or once every six months to a year for those in good condition, and adhere to comprehensive treatment.
Keep seven points in mind to keep away from kidney cancer
1.Smoking: A large number of prospective observations found that smoking is positively related to the development of kidney cancer. The relative risk factor (RR) of kidney cancer in smokers = 2, and the risk of kidney cancer increases in people who have smoked for more than 30 years and smoked filterless cigarettes.
Obesity and hypertension: A prospective study published in the November 2, 2000 issue of the New England Journal of Medicine showed that high body mass index (BMI) and hypertension are two independent factors associated with an increased risk of kidney cancer in men.
3.Occupation: Increased risk of kidney cancer incidence and death has been reported among workers exposed to metal stores, newspaper printers, coke workers, dry cleaners and petrochemicals workers.
4.Radiation: There are statistics that 26 out of 124 cases of tumors caused by the use of a weak alpha particle radiation source were confined to the kidney, but there are no reports of radiation exposure associated with kidney cancer among radiation workers and victims of atomic bombings.
5. Genetic: There are some intrafamilial kidney cancers that are found when chromosomal examination is performed. There is a defect on the third chromosome pair in people with high incidence of kidney cancer. Most familial kidney cancers develop at an early age and tend to be multifocal and bilateral. As many as 28%~45% of patients with a rare hereditary disease, hereditary zebular pemphigoid (VHP) disease, develop kidney cancer.
6. Food and drugs: Investigation found that high intake of dairy products, animal protein and fat and low intake of fruits and vegetables are risk factors for kidney cancer. Coffee may increase the risk of kidney cancer independent of the amount of coffee. In animal experiments, kidney cancer due to female hormones (estrogen) has been proved, but there is no direct evidence in humans yet. Abuse of antipyretic and analgesic drugs, especially those containing finasteride, can increase the risk of renal meningocele. Diuretics may also be a factor that promotes the development of kidney cancer. Animal experiments have concluded that red vine herb, also known as “Chigan”, may induce kidney cancer, and the Korea Food and Drug Safety Agency has asked domestic companies to stop producing red vine herb food additives.
7. Other diseases: In patients on long-term maintenance hemodialysis, there is an increase in the number of cases of cystic degeneration (acquired cystic disease) in the atrophied kidney and then kidney cancer. Therefore, those on dialysis for more than 3 years should have their kidneys examined annually by ultrasound. It has been reported that diabetic patients are more likely to develop kidney cancer. Fourteen percent of kidney cancer patients have diabetes mellitus, which is five times higher than that of the normal population.