A kidney tumor is caused by the formation of abnormal tissue in the kidneys.
This tumor is caused by uncontrolled cell growth and can be benign (non-carcinogenic) or malignant (carcinogenic and potentially fatal).
The kidney is an organ of the urinary tract that serves to form and excrete urine. The other organs of this complex are:
- Ureter
- Bladder
- Urethra
The most common form mainly affects people over the age of 40 and is renal cell carcinoma (RCC).
Generally, it only occurs in the right or left kidney, but it can also occur on both sides.
In 1% of cases, the tumor can spread to the ureter.
Kidney tumors affect more men than women. In fact, there are 17.9 cases per 100,000 men and about 10.3 cases per 100,000 women.
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Types and classification of kidney tumor
Kidney tumors grow in different rhythms, they have different prognosis and respond differently to treatment.
Clear cell carcinoma
This is one of the most common types of renal cell carcinoma. Most of the time, it does not occur in families with BHD syndrome, although recently some doctors have identified more cases than expected.
Clear cell carcinoma has also been found in some hybrid tumors.
Chromophobic renal cell carcinoma
Chromophobic renal cell carcinoma is considered less aggressive compared to other forms of RCC.
In most cases, it does not metastasize in people with Birt–Hogg–Dubé syndrome (BHDS), even if cases of metastasis have been reported.
Chromophobic renal cell carcinoma accounts for around 23% of kidney cancers associated with BHDS.
Papillary renal cell carcinoma
Although it has been diagnosed in BHD syndrome, papillary renal cell carcinoma is rather rare.
Papillary renal cell carcinoma (especially type 2) can be aggressive and metastasize.
Oncocytoma
Oncocytomas are considered benign kidney tumors.
But an oncocytoma, even if benign, can damage the kidneys if it grows in areas important for kidney function or blood flow.
This type of tumor does not spread to other parts of the body.
About 3% of BHDS-related kidney tumors are classified as oncocytic.
Hybrid tumor
Hybrid tumors are a combination of two types.
Different hybrid forms have been found in BHDS-related tumors, including oncocytic, chromophobic, and clear cell.
In a study of 34 kidney tumor patients associated with BHDS, 67% of tumors were oncocytic/chromophobic hybrids.
Other tumors
There are other benign kidney tumor types in BHDS patients, such as kidney angiomyolipomas, which usually occur together with tuberous sclerosis.
Causes of kidney tumor
The exact cause of this tumor has not yet been determined. Medical researchers believe that frequent exposure to chemical toxins, smoking, and drug side effects may be the triggering factors for the development of this type of cancer. Smokers have a 2 to 4 times higher risk of developing it than non-smokers.
Other risk factors include age, gender, occupation, kidney problems, long-term dialysis, obesity, high blood pressure, and some genetic conditions.
In children, the most common form is Wilms tumor, while in adults, mainly renal cell carcinomas (RCC) and transitional cell carcinomas are observed.
RCC forms in the wall of the nephron, whereas transitional cell carcinoma originates in the cells lining the renal pelvis.
In adults, 85% of cases involve renal cell carcinoma.
Symptoms of kidney tumor
In the early stages, a kidney tumor is asymptomatic.
As the disease progresses, some symptoms may appear, such as:
- Recurrent fever
- Fatigue
- Blood in the urine
- Anorexia
- Weight loss
- Abdominal swelling
- Backache
The disease can pass from one kidney to another and to other organs such as the lungs, liver, bones, adrenal gland, spleen, colon and brain.
The lymph nodes located on the diseased kidney may swell.
A metastatic kidney tumor is when it spreads to other organs.
First signs and symptoms of renal cell carcinoma
In some cases, it is difficult to detect a kidney tumor at the initial stage, especially if it is enclosed in the organ, since it does not manifest itself clearly as a result.
Symptoms do not appear until the disease progresses.
Nevertheless, there are some signs that can help in the early diagnosis of this disease:
- Blood clots in the urine (hematuria). Urine may appear reddish or bright orange.
- Anemia due to blood loss.
- Pale skin.
- Constant infections of the kidneys that take a long time to heal.
- Weak to severe pain, especially in the lumbar spine.
- Abdominal pain that can radiate to the back.
- Unexplained weight loss.
- Hypertension
- General weakness and malaise.
- Intermittent fever and fatigue with sweating.
- Formation of a bulge on the side of the abdomen.
- Swelling over the kidneys.
- Stool constipation and excessive thirst due to the increased amount of calcium in the blood.
- Polycythemia, a condition in which the volume fraction of red blood cells in the blood is increased.
Because this condition can cause many different symptoms that can be confused with disorders of other organs, it is sometimes referred to as a large mime.
Diagnosis of kidney tumor
In general, X-rays or CT scans are used to detect abnormal accumulation of kidney cells in the patient and vascularization.
Blood tests and urine tests can reveal the levels of certain substances in the body (for example, creatinine in the blood) that indicate whether the kidneys are functioning properly.
If the presence of a cell mass can be confirmed, the doctor will perform a biopsy to check whether the kidney cells removed are tumor cells.
In addition to these techniques, ultrasound can be used to diagnose kidney cancer.
In certain cases, a tumor is diagnosed when it is already very large, for example, 10 cm or larger.
Determination of the stage of the kidney tumor
Stage I: The tumor is confined to the kidney and is smaller than 7 cm. It does not spread to lymph nodes or the surrounding organs.
Stage II: The tumor is confined to the kidney and is larger than 7 cm. It does not spread to lymph nodes or the surrounding organs.
Stage III: In this phase, there are different combinations of categories T and N. These include tumors of all sizes that have spread to surrounding lymph nodes or the large veins that connect the kidneys to the heart (venous tumor thrombus). In this phase, tumors that spread to other surrounding organs or form distant metastases are not included.
Stage IV: There are different combinations of categories T, N and M. This phase includes any tumors that have spread to surrounding organs such as the colon (colon) or the abdominal wall, as well as those that form distant metastases.
Therapy of kidney tumor
In recent years, various treatment methods have been developed to efficiently cure kidney tumors.
Nowadays, this type of cancer is mainly caused by:
- Operation
- cryoablation,
- radiofrequency ablation,
- embolization,
- Chemotherapy
- biological and targeted therapies.
Healing (recovery) from the kidney tumor is possible only with an early diagnosis.
Surgery
Surgical intervention can be carried out in two ways:
- Removal of the affected kidney along with the adjacent healthy tissues and lymph nodes (nephrectomy)
- Removal of the tumor with a small amount of healthy surrounding tissue (partial nephrectomy)
Nowadays, this operation can be performed laparoscopically. It involves making 3 small incisions (shorter than 1 cm) instead of one long incision.
Alternatively, this neoplasia can be treated with cryoablation, embolization and radiofrequency ablation.
Cryoablation and radiofrequency ablation In cryoablation
, the cancer cells are frozen at extremely low temperatures.
Usually, a hollow needle is inserted through the skin into the tumor and a pressurized gas is used in the needle to freeze the cancer cells.
In radiofrequency ablation, the cancer cells are burned with an electric current.
To do this, a special needle is inserted into the tumor, which can transmit electric current.
Embolization
Embolization blocks the blood and oxygen supply to the tumor to shrink it. In this procedure, a special substance is injected into the main blood vessel, which carries the blood to the kidneys. In this way, the tumor is deprived of oxygen and nutrients that it needs to grow.
This procedure is also known as arterial embolization and is sometimes performed before surgery.
Other treatment options
If the cancer has spread to other areas of the body, chemotherapy, targeted therapy, or biological therapy may be required.
Chemotherapy uses different antitumor drugs to destroy the malignant cells. Sometimes it precedes surgery.
Biological therapy uses specific drugs to stimulate the immune system, destroy the tumor cells.
Targeted therapy is a form of treatment that uses drugs to block abnormal signals that play an important role in the growth and spread of the tumor.
Nutrition for tumors is important for restricting tumor mass growth.
Follow-up examinations after surgical removal of the tumor or kidney to rule out a recurrence:
- visit to the doctor every 6 months;
- blood analyzes every 6 months to check serum creatinine and other parameters of kidney function;
- ultrasound of the abdomen 3 and 6 months after surgery;
- CT of the abdomen once a year over the first 5 years.
The doctor may recommend changes regarding this program depending on the patient’s condition.
What is the life expectancy? Prognosis for patients with kidney tumor
Survival rate
The prognosis is based on the survival rate of people affected by this tumor.
The survival rate is determined after identifying the tumor stage.
In the case of a kidney tumor, the survival rate indicates the patient’s probability of survival five years after diagnosis. On average, over 60% survive the first five years.
According to recent studies, 95% of stage I patients survive five years or more with appropriate therapy. The same is true for 70% of stage II patients. The survival rate in patients with a stage III kidney tumor can vary from 40% to 70%, while it is less than 10% in stage IV patients.
The prognosis for metastatic kidney tumors is very poor, since in these patients the disease is already at a very advanced stage.
The most important factor is the stage of cancer, which determines the survival rate.
However, other factors such as age, treatment success and other diseases are also taken into account for the prognosis.
