Surgery for Wilms Tumors

Surgery is the main treatment for nearly all children with Wilms tumors. It's important that it is done by a surgeon who specializes in operating on children and has experience in treating these cancers.

Removing the tumor

The main goal of surgery is to remove the entire Wilms tumor in one piece, if possible. This is important because Wilms tumors tend to be fragile. Cutting into them makes it more likely that some cancer cells might spread inside the abdomen (belly). Surgeons who operate on these tumors are careful to limit the chance of this type of cancer spread whenever possible.

If the surgeon finds (either with imaging tests done before surgery, or when starting the operation) that the entire tumor can’t be removed safely, surgery might not be done right away. Instead, other treatments may be used first. If these treatments shrink the tumor enough, surgery can then be done more safely.

Depending on the situation, different operations might be used.

Radical nephrectomy

A radical nephrectomy removes the entire kidney and some nearby structures.

This is the most common surgery for a Wilms tumor that’s only in one kidney, because it provides the best chance of making sure all of the tumor is removed. Wilms tumors have often grown large by the time they are found. Sometimes, they are even larger than the kidney itself.

During this operation, the surgeon makes an incision (cut), usually down the middle of the belly. Then the surgeon removes the cancer along with the whole kidney, the adrenal gland that sits on top of the kidney, the surrounding fatty tissue, and the ureter (tube that carries urine from the kidney to the bladder).

Most children do very well afterward with only one kidney.

While it’s not common, if there are larger tumors in both kidneys, both kidneys might need to be removed completely. The child would then need dialysis several times a week. During dialysis, a machine does the job of the kidneys by filtering waste products out of the blood.

Once the child is healthy enough, and if a donor kidney becomes available, a kidney transplant may be an option.

Partial nephrectomy (nephron-sparing surgery)

A partial nephrectomy removes only part of the kidney(s).

For the small number of children who have Wilms tumors in both kidneys, this surgery might be done to try to save some normal kidney tissue. The surgeon may do a radical nephrectomy to remove the kidney containing the most tumor, and then a partial nephrectomy on the other kidney, removing just the tumor and a margin of normal kidney around it. Another option might be to do partial nephrectomies on both kidneys.

Assessing the extent of the disease (surgical exploration)

During surgery to remove the tumor (either radical or partial nephrectomy), another main goal is to determine the extent of the cancer and if it can all be removed.

Lymph nodes (bean-sized collections of immune cells) near the kidney will be removed during surgery to look for cancer cells in them. When cancer cells from a Wilms tumor spread, they often go to the nearby lymph nodes first. Lymph node removal is known as a regional lymphadenectomy.

The other kidney and nearby organs such as the liver may also be looked at closely, and any suspicious areas biopsied (samples taken to be checked for cancer under a microscope).

It’s important for the cancer care team to know if a Wilms tumor has spread to the lymph nodes, the other kidney, or other nearby organs. This helps them determine the stage of the Wilms tumor and further treatment options.

Placing a central venous catheter (port)

If your child is going to get chemotherapy for their Wilms tumor, a surgeon will often insert a small tube into a large blood vessel, usually under the collar bone. This tube is called a central venous catheter, venous access device, or port.

It might be placed during the surgery to remove the tumor, or as a separate operation (especially if chemo is going to be given before the surgery).

One end of the catheter stays outside the body or just under the skin. This can be used to give chemo or take blood samples without the need for more needle sticks into veins. The catheter can stay in place for months.

Possible risks and side effects of surgery to remove a Wilms tumor

Surgery to remove a Wilms tumor is a major operation, and surgeons are very careful to try to limit any problems either during or after surgery.

During surgery

Complications during surgery are rare, but they can happen. This includes bleeding, injuries to major blood vessels or other organs, or reactions to anesthesia.

After surgery

Almost all children will have some pain for a while after the operation, although this can usually be helped with medicines if needed.

Other problems after surgery are not common. But these problems can include internal bleeding, blood clots, infections, or problems with food moving through the intestines.

Kidney function after surgery

Most children do well when only one kidney is removed. But if there are tumors in both kidneys, another concern is the loss of kidney function. Doctors must balance between making sure the tumors are removed completely and removing only as much of the kidney(s) as is needed.

Children who have all or parts of both kidneys removed may need dialysis, and they may eventually need a kidney transplant.

More information about surgery

For more general information about surgery as a treatment for cancer, see Cancer Surgery.

To learn about some of the side effects listed here and how to manage them, see Managing Cancer-related Side Effects.

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References

Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).

Fernandez CV, Geller JI, Ehrlich PF, et al. Chapter 24: Renal Tumors. In: Blaney SM, Adamson PC, Helman LJ, eds. Pizzo and Poplack’s Principles and Practice of Pediatric Oncology. 8th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2021.

National Cancer Institute. Wilms Tumor and Other Childhood Kidney Tumors Treatment (PDQ®)–Health Professional Version. 2024. Accessed at https://www.cancer.gov/types/kidney/hp/wilms-treatment-pdq on November 22, 2024.

National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®): Wilms Tumor (Nephroblastoma). V2.2024. Accessed at https://www.nccn.org on November 22, 2024.

Smith V, Chintagumpala M. Treatment and prognosis of Wilms tumor. UpToDate. 2024. Accessed at https://www.uptodate.com/contents/treatment-and-prognosis-of-wilms-tumor on November 22, 2024.

Last Revised: January 21, 2025

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