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Vol. 66, No. 2 2015
Northeast Florida Medicine
CME
Wilms Tumor Outcomes at a Single Institution and
Review of Current Management Recommendations
Introduction
Wilms tumor, or nephroblastoma, accounts for seven
percent of pediatric malignancies and is the most common
kidney tumor in children and there are approximately 500
cases per year in the United States.
3
Despite its relative
rarity, multiple national and international groups have
made substantial progress in identifying ideal treatment
options for different risk groups in order to maximize
tumor control while minimizing long-termmorbidity. The
two largest groups are the National Wilms Tumor Study
(NWTS), which has subsequently been incorporated into
the Children’s Oncology Group (COG), and the Interna-
Abstract:
Wilms tumor, or nephroblastoma, is the most common
primary renal tumor of children, with about 500 cases per year in
the United States.
1
Treatment is individualized by tumor histology,
stage, and a variety of biologic factors that help determine a
patient’s risk strata, and may include surgery, chemotherapy, and
radiation therapy. The overall survival rates in Wilms, treated
by current techniques, is excellent—approaching 90 percent.
2
Retrospective review of patients treated for Wilms tumors at
Nemours and Wolfson Children’s Hospital in Jacksonville, Florida
between 1994 and 2012, with a median of 11 years of follow-up,
shows a progression free survival of 89 percent and overall survival
of 98 percent to date, with one patient deceased and two patients of
the 64 patient cohort with active disease.
tional Society of Pediatric Oncology (SIOP).
4
These groups
have been studying Wilms since approximately 1970 and
have reached substantially different conclusions regarding
optimal treatment strategy. In essence, SIOP, seeking to
minimize the risk of tumor spillage, recommends upfront
chemotherapy followed by surgery.
5
NWTS/COG, in an
attempt to individualize treatment based upon pathologic
features (to exclude those who might require more morbid
chemo- and radiation therapy), recommends upfront sur-
gery.
6
The treatment per either guideline leads to an overall
survival greater than 90 percent, but the differences in
management have been extensively debated and discussed.
7
Our institution enrolls to the Children’s Oncology Group
and this review will focus on the NWTS/COG staging
system and treatment recommendations.
The first two NWTS randomized trials replaced radi-
ation with chemotherapy in Stage I patients (see COG
staging in Table 1 below). NWTS-3 proved the value of
By Corey Hobbs
1
, MD and Michael Olson
2
, MD, PhD
1
Radiation Oncology Resident, Mayo Clinic Florida, Jacksonville, FL
2
Chief of Radiation Oncology, Baptist Medical Center, Jacksonville, FL; Adjunct Assistant Professor, Mayo Clinic, Jacksonville, FL
Address Correspondence to:
Corey Hobbs, MD
Mayo Clinic
4500 San Pablo Road
Jacksonville, FL 32224
Stage
I
Tumor is confined to the kidney, and was removed completely by surgery.Tumor has not grown into blood vessels next to the kidney.
The tissue layer (the capsule) that surrounds the cancer was not broken during surgery.
II
The cancer grew beyond the kidney, but was completely removed surgically without any apparent cancer left behind. One or more
of the following features may be present:
- The cancer extended beyond the kidney into nearby fatty tissue, but was removed completely
- Cancer extended into blood vessels near the kidney, but was removed
III
This stage refers to Wilms tumors that have not been completely removed.The cancer remaining after surgery is
limited to the abdomen. One or more of the following features may be present:
- Cancer has spread to lymph nodes in the abdomen or pelvis, but not to more distant lymph nodes, such as those within the chest
- Cancer cells are present at the edge of the tissue removed by surgery, indicating that some of the cancer still remains after surgery
- Cancer “spilled” into the abdominal cavity before or during surgery
- The cancer invaded nearby vital structures, and the surgeon could not remove it completely
- Deposits of tumor (tumor implants) are found along the lining of the abdominal cavity
IV
Hematogenous metastases, including non-regional lymph nodes
V
Bilateral tumors
Table 1: COG Staging System for Wilms Tumor
