Treatment of Wilms Tumor, By Type and Stage

How type, stage, and risk group guide treatment for Wilms tumor

Treatment for Wilms tumor is based mainly on the stage of the cancer and whether its histology is favorable or anaplastic. (See Wilms Tumor Staging for an explanation of staging and histology.)

Other factors can influence treatment as well, including:

• The child’s age
• If the tumor cells have certain chromosome changes
• The size (weight) of the main tumor

These factors are combined to assign the child to a risk group, which is used to help guide treatment.

In the United States and Canada, doctors prefer to use surgery as the first treatment for Wilms tumor in most cases. Chemotherapy (and possibly radiation therapy) are then given afterward.

In Europe and some other parts of the world, doctors prefer to start the chemotherapy before surgery. The results from these approaches seem to be about the same.

Most often, the stage and histology of the cancer are actually determined when surgery is done to remove the cancer. This is because the true extent of the tumor often can’t be determined by imaging tests alone. The doctors use what they learn during surgery to guide further treatment.

But sometimes it’s clear that the cancer has already spread beyond the kidney, based on imaging tests even before surgery is done. This can affect the order in which treatments are given, as well as the extent of surgery.

Treating stage I Wilms tumors

Stage I Wilms tumors are only in the kidney, and surgery has completely removed the tumor along with the entire kidney, nearby structures, and some nearby lymph nodes.

Favorable histology

Children younger than 2 years with small tumors (weighing less than 550 grams) may not need further treatment after surgery. But they need to be watched closely, because the chance the cancer will come back is slightly higher than if they also got chemo.

If the cancer does come back, the chemo drugs actinomycin D (dactinomycin) and vincristine (and possibly more surgery) are very likely to be effective at this point.

For children older than 2 and for those of any age who have larger tumors, surgery is usually followed by chemo for several months, with the drugs actinomycin D and vincristine.

If the tumor cells have certain chromosome changes, the drug doxorubicin (Adriamycin) may be given as well.

Anaplastic histology

For children of any age who have tumors with anaplastic histology, surgery is usually followed by radiation therapy to the area of the tumor, along with chemo with actinomycin D, vincristine, and possibly doxorubicin (Adriamycin) for several months.

Treating stage II Wilms tumors

Stage II Wilms tumors have grown outside the kidney into nearby tissues, but surgery has removed all visible signs of cancer.

Favorable histology

After surgery, standard treatment is chemo with actinomycin D and vincristine. If the tumor cells have certain chromosome changes, the drug doxorubicin (Adriamycin) may be given as well. The chemo is given for several months.

Anaplastic histology, with focal (only a little) anaplasia

When the child recovers from surgery, radiation therapy is given over several weeks. After this is finished, chemo (doxorubicin, actinomycin D, and vincristine) is given for about 6 months.

Anaplastic histology, with diffuse (widespread) anaplasia

After surgery, children with these tumors get radiation over several weeks. This is followed by a more intense type of chemo using the drugs vincristine, doxorubicin, etoposide, cyclophosphamide, and carboplatin. Mesna (a drug that helps protect the bladder from the effects of cyclophosphamide) is given along with this, for about 6 months.

Treating stage III Wilms tumors

Surgery cannot remove these tumors completely because of their size or location, or for other reasons. In some cases, surgery may be postponed until other treatments are able to shrink the tumor first (see below).

Favorable histology

Treatment is usually surgery if it can be done, followed by radiation therapy over several days. This is followed by chemo with 3 drugs (actinomycin D, vincristine, and doxorubicin). If the tumor cells have certain chromosome changes, the drugs cyclophosphamide and etoposide may be given as well. Chemo is given for about 6 months.

Anaplastic histology, with focal (only a little) anaplasia

Treatment starts with surgery if it can be done, followed by radiation therapy over several weeks. This is followed by chemo, usually with 3 drugs (actinomycin D, vincristine, and doxorubicin) for about 6 months.

Anaplastic histology, with diffuse (widespread) anaplasia

Treatment starts with surgery if it can be done, followed by radiation therapy over several weeks. This is followed by chemo, usually with the drugs vincristine, doxorubicin, etoposide, cyclophosphamide, and carboplatin, along with mesna (a drug that helps protect the bladder from the effects of cyclophosphamide). Chemo lasts about 6 months.

Tumors that are very large and/or are in places that make them hard to remove

In some instances, the tumor may be very large or may have grown into nearby blood vessels or other structures so that it can’t be removed safely.

In children with these tumors, a small biopsy sample is taken from the tumor to be sure that it’s a Wilms tumor and to determine its histology. Then chemo is started. Usually, the tumor will shrink enough within several weeks so that surgery can be done. If not, then radiation therapy might be given as well. Chemo will be started again after surgery. If radiation was not given before surgery, it’s given after surgery.

Treating stage IV Wilms tumors

These tumors have already spread to distant parts of the body (such as the lungs) at the time of diagnosis. As with stage III tumors, surgery to remove the tumor might be the first treatment, but it might need to be delayed until other treatments can shrink the tumor (see below).

Favorable histology

Surgery to remove the tumor is the first treatment, if it can be done. This is typically followed by chemo, usually with 3 drugs (actinomycin D, vincristine, and doxorubicin) for about 6 months. If the tumor cells have certain chromosome changes, the drugs cyclophosphamide and etoposide may be given as well.

Radiation therapy may be given to the abdomen if there is still some cancer left after surgery. If the cancer has spread to the lungs, low doses of radiation might also be given to that area, if the cancer doesn’t go away after 6 weeks of chemo or if the tumor cells have certain chromosome changes.

Anaplastic histology

Treatment might start with surgery if it can be done. This is often followed by chemo with the drugs vincristine, doxorubicin, etoposide, cyclophosphamide, and carboplatin, along with mesna given for about 6 months. If the tumor cells have diffuse (widespread) anaplasia, some doctors might try the chemo drugs irinotecan and vincristine first instead. The treatment would then be adjusted if the tumor shrinks in response to these drugs.

Radiation therapy may be given to the abdomen if there is still some cancer left after surgery. Low doses of radiation will also be given to the lungs if the cancer has spread there.

Tumors that are very large and/or are in places that make them hard to remove

If the tumor is too large or has grown too much to be removed safely with surgery first, a small biopsy sample may be taken from the tumor to be sure it’s a Wilms tumor and to determine its histology. Chemo and/or radiation therapy may then be used to shrink the tumor. Surgery might be an option at this point. This would be followed by more chemo 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 chemo and radiation therapy.

Treating stage V Wilms tumors

Treatment for children with bilateral Wilms tumors (tumors in both kidneys) is unique for each child, although it typically includes surgery, chemo, and radiation therapy at some point.

Biopsies (tissue samples) of tumors in both kidneys and of nearby lymph nodes might be taken first. However, not all doctors feel this is needed because when both kidneys have tumors that look like Wilms tumors, the chance that they are Wilms tumors is very high.

Chemo is typically given first to try to shrink the tumors. The chemo drugs used most often include vincristine, dactinomycin, and doxorubicin. The goal is to shrink the tumors and typically do surgery (partial nephrectomy) 6 to 12 weeks later. Chemo and/or radiation might then be done after surgery.

If the cancer is in both kidneys and has also spread to other parts of the body, other treatments might be used as well (see treating stage IV Wilms tumors, above).

If not enough functioning kidney tissue is left after surgery (such as if both kidneys need to be removed completely), a child may need dialysis, a procedure where a special machine filters waste products out of the blood, several times a week. If there is no sign of any cancer after a year or two, a donor kidney transplant may be done.

Treating recurrent Wilms tumors

Sometimes a Wilms tumor recurs (comes back) after treatment. In this situation, the prognosis (outlook) and treatment for a child depends on their prior treatment, the cancer’s histology (favorable or anaplastic), and where in the body it recurs.

The outlook is generally better for recurrent Wilms tumors with the following features:

• Favorable histology
• Initial diagnosis of stage I or II
• Initial chemo with vincristine and actinomycin D only
• No previous radiation therapy

The usual treatment for these children is surgery to remove the recurrent cancer (if possible), radiation therapy (if not already given to the area), and chemo, often with drugs different from those used during first treatment.

Recurrent Wilms tumors that do not have the features above are harder to treat. Children with these tumors are usually treated with aggressive chemo, such as the ICE regimen (ifosfamide, carboplatin, and etoposide) or with other regimens being studied in clinical trials.

Very high-dose chemo followed by a stem cell transplant (sometimes called a bone marrow transplant) might also be an option in this situation, although this is still being studied.