Below are some of the most common treatment approaches for patients with Wilms tumors. Most children with this type of cancer are treated in clinical trials developed by the Children's Oncology Group. The goal of these studies is to cure as many children as possible while limiting side effects by giving as little treatment as is necessary. This is done by comparing the current best treatment with one the doctors think might be better. Because of this, treatment may differ slightly from those described below in some cases.
Treatment for Wilms tumor is based mainly on the stage of the cancer and whether its histology (appearance under the microscope) is favorable or unfavorable. In the United States, doctors prefer to use surgery as the first treatment in most cases, and then give chemotherapy (and possibly radiation therapy) afterward. In Europe, experts prefer to begin the chemotherapy before surgery. The results seem to be the same.
Stage I (favorable or unfavorable histology)
These tumors are still only in the kidney. Standard treatment starts with surgery to remove the kidney containing the tumor (an operation called radical nephrectomy).
Children younger than 2 years with small tumors (weighing less than 550 grams) with favorable histology may not need further treatment, such as chemotherapy. But they need to be watched closely because the chance the cancer will come back is slightly higher than if they had chemotherapy. If the cancer does come back, chemotherapy (actinomycin D and vincristine) is very likely to be effective at this point.
For children older than 2 and for those of any age with larger tumors or unfavorable histology, surgery is usually followed by chemotherapy with actinomycin D (dactinomycin) and vincristine, which is given for 18 weeks. Children who have unfavorable histology tumors may also get radiation therapy.
Stage II
These tumors have grown outside the kidney into nearby tissues, but surgery can remove all visible signs of cancer.
Favorable histology: Standard treatment is surgery (radical nephrectomy), followed by chemotherapy with actinomycin D and vincristine. The chemotherapy is given for 18 weeks.
Unfavorable histology with focal (only a little) anaplasia: Treatment begins with surgery (radical nephrectomy). When the child recovers, radiation therapy is given to the abdomen for 6 or 7 days. When this is finished, chemotherapy (doxorubicin, actinomycin D, and vincristine) is given for about 6 months.
Unfavorable histology with diffuse (widespread) anaplasia: These children also get surgery (radical nephrectomy) and radiation to the abdomen for several days. This is followed by more intense chemotherapy using the drugs vincristine, doxorubicin, etoposide, and cyclophosphamide along with mesna (a drug that protects the bladder from the effects of cyclophosphamide), which is given for about 6 months.
Stage III
Favorable histology: Treatment is usually surgery (radical nephrectomy) followed by radiation therapy to the abdomen over several days. This is followed by chemotherapy with 3 drugs (actinomycin D, vincristine, and doxorubicin) for about 6 months.
Unfavorable histology with focal (only a little) anaplasia: Treatment begins with surgery (radical nephrectomy) followed by radiation therapy to the abdomen for several days. This is followed by chemotherapy, usually with 3 drugs (actinomycin D, vincristine, and doxorubicin) for about 6 months.
In rare instances the tumor may be very large or may have grown into nearby blood vessels or other structures so that it cannot be removed safely. In these cases a small tissue sample is taken from the tumor for testing to be sure that it is a Wilms tumor and then chemotherapy is started. If there is no response or not enough response to chemotherapy, then radiation therapy is given to shrink the tumor. Usually the tumor will shrink within several weeks so that a radical nephrectomy can be done. Chemotherapy starts again after surgery. If radiation was not given before surgery, it is given after surgery.
Unfavorable histology with diffuse (widespread) anaplasia: Treatment begins with surgery (radical nephrectomy) followed by radiation therapy to the abdomen for several days. This is followed by chemotherapy, usually with the drugs vincristine, doxorubicin, etoposide, and cyclophosphamide along with mesna (a drug that protects the bladder from the effects of cyclophosphamide). Chemotherapy lasts about 6 months.
In some instances the tumor may be very large or may have grown into nearby blood vessels or other structures so that it cannot be removed safely. In these patients a small tissue sample is taken from the tumor for testing to be sure that it is a Wilms tumor and then chemotherapy is started. If there is no response or not enough response to chemotherapy, then radiation therapy is given to shrink the tumor. Usually the tumor will shrink enough within several weeks so that a radical nephrectomy can be done. Chemotherapy will be started again after surgery. If radiation was not given before surgery, it is given after surgery.
Stage IV
These tumors have already spread to distant parts of the body at the time of diagnosis.
Favorable histology and unfavorable histology with focal (only a little) anaplasia: Standard treatment is surgery (radical nephrectomy), followed by radiation therapy to the abdomen. The entire abdomen will be treated if there is still some cancer in the abdomen. If the cancer has spread to the lungs, low doses of radiation will also be given to that area. This is followed by chemotherapy with 3 drugs (actinomycin D, vincristine, and doxorubicin) for about 6 months.
Unfavorable histology with diffuse (widespread) anaplasia: Treatment begins with surgery (radical nephrectomy) followed by radiation therapy to the abdomen. The entire abdomen will be treated if there is still some cancer in the abdomen. Low doses of radiation will also be given to both lungs if there is spread to the lungs. This is followed by chemotherapy with the drugs vincristine, doxorubicin, etoposide, and cyclophosphamide along with mesna given for about 6 months.
In cases where the tumor is too large or has grown too extensively to be safely treated with surgery, chemotherapy and/or radiation therapy may be used first to shrink the tumor. Surgery may be an option at this point. This would be followed by more chemotherapy (and radiation therapy if it wasn't given already).
For stage IV cancers that have spread to the liver, surgery may be an option to remove any liver tumors that still remain after chemotherapy and radiation therapy.
Stage V
Treatment for children with tumors in both kidneys is unique for each child, although it typically involves surgery, chemotherapy, and radiation therapy at some point.
Usually biopsies (tissue samples) of tumors in both kidneys and of lymph nodes are taken first. Chemotherapy is then given to try to shrink the tumors. The drugs used will depend on the extent and histology of the tumors. After about 6 weeks of chemotherapy, a second operation may be done. The tumors may be removed at this point if enough normal kidney tissue can be left behind. If the cancer is still present, treatment may include more chemotherapy, radiation therapy, and/or surgery to try to remove the tumors but not the entire kidneys.
If not enough functioning kidney tissue is left after surgery, a child may need to be placed on dialysis, a procedure where a special machine filters waste products out of the blood several times a week. If there is no evidence of any cancer after a year or two, a donor kidney transplant may be done.
Recurrent Wilms tumor
The prognosis and treatment for children with Wilms tumor that recurs (comes back after treatment) depends on their prior treatment and the cancer's histology (favorable or unfavorable). The outlook is generally better for recurrent Wilms tumor with the following features:
- Favorable histology
- Initial stage of I or II
- Initial chemotherapy with vincristine and actinomycin D only
- No previous radiation therapy
- Recurrence at least 12 months after initial diagnosis
The usual treatment for these children is surgery to remove the recurrent cancer (if possible), radiation therapy, and chemotherapy, often with drugs different from those used during first treatment.
Recurrent Wilms tumors that do not have the features listed above are much harder to treat. These children are usually treated with aggressive chemotherapy, such as the ICE regimen (ifosfamide, carboplatin, and etoposide) or others being studied in clinical trials. Very high-dose chemotherapy followed by a stem cell transplant (sometimes called a bone marrow transplant) may also be an option in this situation.
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