A great deal of progress has been made in treating Wilms' tumor over the last 25 years. Nine out of ten children are successfully treated with surgery, chemotherapy and sometimes, radiation therapy.
Many improvements in treatments have been due to the work of the Children's Oncology Group (formerly the National Wilms Tumor Study Group). This group organizes scientific studies (clinical trials) of new treatments. Today, most children with Wilms tumor are enrolled and treated in a clinical trial, so that the best treatments available can be improved even further.
Wilms tumors are relatively rare therefore it is important to seek care at an experienced children’s cancer center. A team approach that includes the child's pediatrician as well as specialists at the childhood cancer center where the treatment will be provided is recommended. Once a Wilms' tumor is discovered, children should begin treatment quickly. Wilms' tumors are often quite large by the time they are discovered, and these tumors tend to grow rapidly.
Nearly all children’s cancer centers are members of the Children’s Oncology Group and therfore the treatment approach will be almost identical in these centers. Treatment of Wilms tumor usually involves surgery, chemotherapy, and sometimes radiation therapy. If any cancer remains after the initial operation, radiation therapy or further surgery may be needed.
The first goal is to remove the tumor from the involved kidney or major site, even if the cancer has spread (metastasized) to other parts of the body. Sometimes, the tumor can be too large to remove immediately and may have spread into nearby blood vessels, other vital structures, or may be found in both kidneys. In these patients, doctors sometimes use chemotherapy to shrink the tumor before removing it later in the course of therapy..
Surgery
Surgery is the main treatment for Wilms tumor. The most common operation for Wilms tumor is called a radical nephrectomy. In this procedure, a surgeon removes the cancer along with the entire kidney, the ureter (the tube that carries urine from the kidney to the bladder), and fatty tissue that surrounds the kidney.
At the time of the radical nephrectomy, a regional lymph node sampling is performed. In this procedure, the surgeon removes the lymph nodes next to the kidney. Lymph nodes are bean-sized glands that are part of the immune system and help to fight infections. Many cancers spread to the lymph nodes. Sampling the lymph nodes helps assess the degree of spread within the abdomen.
During surgery, the liver and the other kidney will also be examined. Any suspicious areas may be biopsied meaning that tissue samples are removed for examination under a microscope. If imaging tests such as a chest x-ray or CT scan suggest that the Wilms tumor has spread to the lungs, the surgeon may also take a tissue sample or remove the nodule completely to determine if it is a metastasis (spread of the Wilms' tumor). This may be done through a separate incsion in the chest wall using a special operating telescope. This procedure is called Video Assisted Thoracoscopic Surgery (VATS) and can be used to remove tumors in the lung with minimal invasive techniques. Knowing whether or not a Wilms tumor has spread to the lymph nodes, liver, or the other kidney is important in determining the stage of the disease as well as in choosing treatment.
More information about surgery
Chemotherapy
Chemotherapy is systemic therapy. This means that the drugs used to treat the cancer are added to the bloodstream, and circulate through the body to reach and destroy the cancerous cells. Chemotherapy is given to all children with Wilms tumor. It may be given to:
- Shrink a tumor too large to remove surgically
- After surgery to destroy any tumor cells that might be circulating in the body (called adjuvant therapy) and
- Treat cancer that has spread to organs beyond the kidney.
Chemotherapy drugs are injected into a vein in different combinations and dosages at different times, depending on the type and stage of Wilms tumor. Chemotherapy is ordered by the pediatric oncologist and is usually given by a nurse. Most chemotherapy for Wilm’s tumor can be given in an outpatient setting, however in some cases the treatment must be given in the hospital.
While chemotherapy kills cancer cells, it can also damage some normal cells. Careful attention is given to avoid or minimize side effects. The side effects of chemotherapy depend on the type of drugs, the amount taken, and the length of time they are taken. It is important to tell the cancer care team if the child has any side effects. The side effects can often be treated or, prevented with other medicines.
Stage I and II treatment
The chemotherapy agents used for Wilms tumor treatment vary according to stage. Lower stage disease (stages I,II) with favorable histology is usually treated with two chemotherapy medicines, vincristine and dactinomycin. These medicines are given intravenously, initially on a weekly schedule and then every 2-3 weeks. Most, if not all of the chemotherapy for stage I-II tumors is done as an outpatient and the side effects are mild, usually not requiring hospitalization. Radiation therapy is not required in Stages I-II favorable histology disease.
Stage III and IV treatment
Stage III and IV disease and unfavorable histology tumors as well as clear cell sarcoma of the kidney and malignant rhabdoid tumor are treated with 3 or more chemotherapy agents depending on stage and histology. Radiation therapy is given to the abdomen and to other sites of metastases. Chemotherapy is given by vein and can usually be given as an outpatient. Occasionally treatment for these stages of disease requires hospitalization and is often associated with more serious side effects.
The risks associated with more intensive chemotherapy are:
- Greater chance of blood count changes that may result in a need for transfusions of blood or platelets
- Risk of fever and infection that may require hospitalization for antibiotics
Medicines used for higher stage tumors include vincristine, dactinomycin, doxorubicin, cyclophosfamide, carboplatin, etoposide or ifosfamide (rarely) The choice of agents used depends on the stage and status of current research treatment protocols.
More information about chemotherapy
Radiation therapy
Radiation therapy uses high-energy beams to kill cancer cells. External beam radiation therapy focuses energy onto the cancer using a radiation source outside the body. This type of radiation therapy is often used along with surgery in more advanced cases of Wilms tumor (stages III, IV, and V) that have spread beyond the kidney or are not able to be completely removed at surgery).It is used in Stage I and II disease only if there is evidence of unfavorable histology.
Side effects of radiation therapy can include:
- Nausea
- Diarrhea
- Fatigue
- Sunburn-like skin changes
More information about radiation therapy
Shirley Perry, RN, Oncology Nurse Practitioner, Stollery Children's Hospital
Reviewed by the CureSearch.org Medical Editorial Board
May 2008