Kidney Tumors

Essential Information

Summarize

Kidney tumors are tumors in which the tumor cells originate within the kidney tissue. There are a wide variety of kidney tumors in children, more than a dozen in all. Of these, nephroblastoma (also known as Wilms' tumor) accounts for about 87% of kidney tumors in children and 6% of all childhood tumors, making it the most common type of kidney tumor in children. The tests, treatments, and post-treatment outcomes required for each child will vary depending on the specific tumor type, tumor stage, treatment options, and the individual's response to treatment.

Classification & Stage

List of kidney tumors in children:
Nephroblastoma (Wilms Tumor)
Renal cell carcinoma (Renal cell carcinoma stage)
Rhabdoid Tumor of the Kidney (Rhabdoid Tumor of the Kidney)
Clear Cell Sarcoma of the Kidney (Cell Clear Sarcoma of the Kidney)
Congenital Mesoblastic Nephroma (Congenital Mesoblastic Nephroma)
Primitive neuroectodermal tumor /Ewing sarcoma of the kidney)
Primary renal myoepithelial carcinoma (primary renal myoepithelial carcinoma)
Cystic Partially Differentiated Nephroblastoma
Multilocular Cystic Nephroma
Primary Renal Synovial Sarcoma
Renal Anaplastic Sarcoma
Desmoplastic small round cell tumors
Neuroepithelial tumors of the kidney
Metanephric Adenoma
Renal lymphoma
Juxtaglomerular cell tumor
Renal Medullary Carcinoma
Ossifying renal tumor of infancy
Angiomyolipoma (renal angiomyolipoma)
Nephroblastomatosis (Nephroblastoma)

Clinical manifestations

Each cell in the human body is like a miniature machine that consumes energy to keep functioning and then eliminates the remaining energy and other wastes. The "wastes" produced by these cellular machines include carbon dioxide, urea and creatinine, which are produced by protein and muscle metabolism. Carbon dioxide is eliminated from the lungs through respiration, while the kidneys are important organs for the elimination of urea and creatinine.

The human body has two kidneys, one on each side of the body, located in the lower back. Each kidney has about a million filtering units that process waste, called "renal units". Blood enters the renal unit from the renal artery, where it removes waste products and reabsorbs water and chemicals needed by the body, and the processed blood flows back into the body through the renal vein.

And the waste products that are processed by the kidney units along with water end up as urine. The urine travels down two long tubes called ureters into the bladder to be stored. When enough urine is stored in the bladder, the body produces a urination response and the urine is passed out of the body down the urethra.

What is the structure of the kidney itself like? It can be seen more clearly in the figure below. The outermost layer of the kidney is the renal cortex, while the renal medulla, calyces and renal pelvis are in the deeper part of the kidney.

The reason why it is important to understand the structure of the kidney is that different kidney cancers may originate in different parts of the body. And the different sites of tumor occurrence are very important for doctors to make diagnosis and identification.

Among young children, abdominal mass is the most common first symptom of kidney cancer. Therefore, when parents find abdominal lumps in young children, they should pay attention to it and consult the doctor as soon as possible.

Overall, the clinical manifestations of renal tumors in children are diverse and not entirely consistent. Symptoms are categorized into local and systemic manifestations.

:: Localized manifestations: for example, the most common manifestation of nephroblastoma is an enlarged abdomen with a palpable mass, and some children present to the hospital with hematuria, abdominal pain or fever.

● Systemic manifestations: About 25% of children will have abnormal renin secretion and high blood pressure due to the tumor. The enlarged abdomen caused by the tumor may also cause the diaphragm to rise, resulting in shortness of breath. Some children may also have congenital malformations such as iris defects, genitourinary malformations, mental retardation syndrome, and hemihypertrophy.

Examination & Diagnosis

To confirm the diagnosis of a kidney tumor, a more detailed assortment of tests is usually done to help the doctor's diagnosis. Specific tests may include the following:

Physical examination and history taking

Physical examination includes checking for lumps or other abnormalities in the body. A medical history is taken, including what illnesses have been present in the past and how they have been treated.

Complete Blood Count (CBC)

Blood will need to be drawn to check the number of red blood cells, white blood cells and platelets; the amount of hemoglobin in the red blood cells (hemoglobin is the protein that carries oxygen), and the percentage of red blood cells in the blood sample.

blood biochemistry

A blood draw is needed to test the amount of certain substances released into the bloodstream by the body's organs and tissues. This test is done to check if the liver and kidneys are functioning properly.

Urinalysis

The reflection of urine on kidney function is multi-faceted. In addition to checking the color of urine, we will also check whether the urine contains sugar, protein, blood and bacteria, etc. All of these data are important in determining the health of the kidneys.

Imaging
When a doctor suspects that a patient has a kidney tumor, imaging tests are often used to determine the location of the lesion and whether it has spread. Commonly used diagnostic imaging modalities include ultrasound, chest and abdominal x-rays, CT, dynamic CT scans, magnetic resonance imaging (MRI), PET-CT, and bone scans.

pathological examination

This is a relatively backward test, but it is also the gold standard for confirming the nature of the tumor. Doctors usually start with non-invasive or less invasive tests in the front. When needed, the doctor will remove some cells or tissues from the child's body through traditional or minimally invasive surgery, and a pathologist will make a specimen to observe under a microscope whether there is a tumor, and if it is a tumor, whether it is malignant or not. The biopsy can be taken before treatment, after chemotherapy or after surgical removal. The need for a biopsy depends on many factors:

● Size of the tumor
● The stage of the cancer
● Whether the cancer is present in one or both kidneys
● Whether the cancer is clearly shown on imaging tests
● Whether the tumor can be removed surgically
● Whether the patient is participating in a clinical trial

Clinical Management

Commonly used treatments for kidney tumors include surgery, chemotherapy, radiotherapy, etc. Newer treatments also include bioimmunotherapy, targeted therapy, stem cell transplantation, etc.

Surgery can be performed in a variety of ways. Most of the time, we want to remove the tumor directly, but when direct surgical removal of the tumor is not feasible, there is also the treatment option of arterial embolization to shrink the tumor. This method involves creating a small incision and inserting a catheter into the main blood vessel that flows to the kidney. Through the catheter, a small piece of special gelatin sponge is injected into the blood vessel. This gelatin sponge will "starve the cancer cells" by blocking the flow of blood to the kidneys and preventing the cancer cells from obtaining oxygen and other substances needed for growth.

Some children may receive chemotherapy or radiation therapy after surgery to kill any remaining cancer cells and reduce the risk of recurrence. This type of treatment given after surgery to reduce the risk of the cancer coming back is called adjuvant therapy.

The outcome of the disease and survival after treatment are collectively referred to as prognosis. The prognosis of renal tumors is related to the specific tumor type, stage, treatment regimen, and individual response to specific treatments. Early detection and treatment often improves the prognosis, with children surviving longer and having a better quality of life.

Cutting-edge Therapeutic & Clinical Research

Treatments are categorized into standard and clinical trial treatments. The purpose of clinical trials is to help improve current treatments or to try new treatment options. The vast majority of conventional cancer treatments used today are the result of previous clinical trials. Clinical trials can tell whether a new cancer treatment is safe, effective, and better than existing conventional treatments. When a clinical trial shows that a new treatment is better than the standard treatment, the new treatment may become the standard treatment.

Different clinical trials, because they have different purposes, may select patients with different disease characteristics to participate. Some trials only allow patients who have not yet received other treatments to join, while others are designed to try new approaches for patients who are not getting better. Other trials are designed to test new ways of preventing recurrence or to minimize the side effects of cancer treatment.

Clinical trials are conducted in many areas. The best website to look up clinical trials is ClinicalTrials.gov. People can search for trials based on the type of cancer, the age of the patient, and where the trial is being conducted.

Some clinical trials require regular follow-up visits even after treatment has ended, and the results of these tests will tell you if your child's condition has changed or if the cancer has returned. This is called a retest. Because childhood cancers are so rare, in most cases there is no standard treatment that everyone recognizes. If the standard treatment is not working well and there is an appropriate clinical trial, we encourage you to learn more about it and consider participating.

From a larger perspective, patients who participate in clinical trials are helping to advance future treatments regardless of the outcome. Even if a clinical trial does not result in an effective new treatment, it can go some way toward answering many important questions and help cancer research move forward in a better way.

Clinical trials currently open in the United States for pediatric kidney tumors include:

Cabozantinib-S-Malate for Young Patients with Recurrent, Refractory or Newly Diagnosed Sarcoma, Wilms' Tumor or Other Rare Tumors
● Status: Open
● Age: 2 to 30 years
● Gender: Male or Female
● Location: 123 locations
● Website: https://clinicaltrials.gov/ct2/show/NCT02867592

Molecularly Directed Therapy for Childhood Cancer
● Status: Open
● Age: 13 months to 21 years
● Sex: male or female
● Location: 5 sites
● URL: https://clinicaltrials.gov/ct2/show/NCT02162732

Directed Radiation for Ewing Sarcoma, Rhabdomyosarcoma, or Nephroblastoma Lung Metastases
● Status: Open
● Age: 21 and under
● Sex: male or female
● Location: 3 locations
● URL: https://clinicaltrials.gov/ct2/show/NCT02581384

Study for young patients with renal tumors
● Status: Open
● Age: 29 and under
● Sex: male or female
● Location: 194 sites