Tumor spillage and Wilm's tumor: types and implications

Tumor spillage during resection of a Wilm's tumor has substantial implications on prognosis and therapy. Spillage immediately upstages a patient to Stage III, and depending on the type of spillage, commits the patient to either flank (local spillage) or total abdominal radiation (diffuse spillage).

Intraoperative recognition and documentation of spillage, whether pre-exiting or secondary to manipulation, thus has substantial implications on adjuvant therapy. With that in mind, it is important understand the different types of spillage or peritoneal soilage by tumor.

Based on the COG's AREN03B2 Renal Biology Protocol handbook (2010), the peritoneum is concidered soiled (tumor spill) when:

1. There is intraoperative tumor spillage
2. The tumor is biopsied
3. The tumor has ruptured

Spillage occurs whenever the tumor capsule is violated. If adherent organs (eg. diaphragm) are resected without violation of the capsule, this is not considered spillage. Whenever one cuts across tumor, including tumor present within vessels, or the tumor is removed in more than one piece, spillage is assumed to have occurred.

Tumor biopsy, whether done through a percutaneous anterior or retroperitoneal approach, or using an open approach, is considered local spillage unless indicated otherwise by the surgeon.

Tumor rupture can be spontaneous or post-traumatic with subsequent tumor cell dissemination in the peritoneal cavity. Tumor rupture is usually considered diffuse soilage, though in some cases it may be clearly isolated to the retroperitoneal space and considered local spillage. The presence of a hematoma implies tumor cell spread and diffuse soilage.

Because of the various types of soilage, and their different implications (either flank or total abdominal radiation), the surgeon should completely and clearly document how the soilage occurred and whether it was thought to be diffuse or local. If tumor thrombus is encountered, the surgeon must clearly describe whether it was removed en bloc, in more than one piece, and if residual thrombus was thought to be left behind.