Wilms Tumor Protocol Violations: Practice Gap discussion at Update Course 2018

When performing nephrectomy for Wilms tumor, lymph node sampling is mandatory according to protocols.

If histologically negative lymph nodes are not documented during Wilms tumor nephrectomy, they are assumed to be positive, which increases the stage and requires increased chemotherapy.

Failure to sample lymph nodes during Wilms tumor nephrectomy is an identified practice gap by the Cancer Committee and COG publications.

The presence of metastatic disease in the lung does not preclude treating the primary tumor with nephrectomy, because this affects whether radiation therapy is required.

There is both a local stage and a patient stage for Wilms tumor.

On the ACS pediatric surgery blog, a similar question showed that overwhelmingly the presence of lymph node metastases led people to choose biopsy and chemotherapy, which is incorrect.

Regardless of pulmonary metastatic disease, if the primary tumor can be removed without removing other organs, nephrectomy should be performed because it decreases radiation therapy requirements.

The child will receive stage 4 metastatic chemotherapy regardless, but performing biopsy counts as local spillage and requires radiation therapy to the flank or abdomen.

Local disease should be treated differently than systemic disease in Wilms tumor.

Oncologists want measurable disease to assess response to chemotherapy.

According to Dr. Shamberger, there are radiographic criteria for single lung nodules; if it looks like a metastasis you proceed, but if it does not look like a metastasis you can biopsy it to prove it is not a met and avoid chemotherapy.

In SIOP protocols, they perform percutaneous biopsy of the primary tumor and treat with chemotherapy.

The American College of Surgeons registry data shows improvement with fewer patients receiving nephrectomies without lymph node sampling since educational efforts began.