Laparoscopic nephrectomy for Wilms' tumor: Can we expand on the current SIOP criteria?

Summary

Introduction

Wilms' tumor now has a good overall prognosis with open radical nephrectomy having been the mainstay of surgical treatment. Recently laparoscopic nephrectomy (LN) has been growing in popularity. The aim of our study was to review our indications and outcomes for laparoscopic resections for Wilms' tumor and compare indications with International Society of Paediatric Oncology (SIOP) criteria for LN.

Material and methods

Patient demographics, preoperative management, surgical data, respect of SIOP criteria, complications, disease outcome, and follow-up were recorded on consecutive children who underwent nephrectomy for Wilms' tumor.

Results and discussion

Fifty-four consecutive children with Wilms' tumor underwent a nephrectomy; 20 had a LN (Table). Nine of 20 (45%) patients who had LN did not meet SIOP criteria for LN. No patients had an intraoperative tumor rupture and one patient had positive margins because of preoperative rupture. There were two conversions: one caused by difficulty accessing the renal hilum and the other caused by difficulty maintaining oxygen saturations. There was one local recurrence.

Conclusion

SIOP criteria are conservative and safe. Indications can be extended for teams experienced in surgical oncology and laparoscopy after agreement at a multidisciplinary meeting (MDM).

Table. Comparison table of open versus laparoscopic nephrectomy.

Empty Cell	Open nephrectomy	Laparoscopic nephrectomy
Total	34	20
SIOP criteria for laparoscopic nephrectomy met	0	11
Margins involved	5	1
Lymph nodes harvested (mean)	4.6	4.8
Recurrences	5	1

Introduction

Outcomes for Wilms' tumors have improved in the last few decades and are now approaching 90% cure rates [1], [2], [3]. Surgery still has an important role in the treatment pathway. Complete resection with clear margins and without tumor spillage reduces the risk of local and abdominal recurrence thereby avoiding the need for doxorubicin and radiotherapy [4], [5]. As a result minimally invasive surgery did not play a role in pediatric oncology surgery, and in particular in the management of Wilms' tumors, as laparoscopy was not felt to provide the same level of control and delicate handling of the tumor, leading to concern over increased tumor rupture and upstaging of the child. Recent technical innovations and evidence that neoadjuvant chemotherapy in the SIOP protocol caused tumor shrinkage and encapsulation rendering them more resistant to tumor spillage [6] have made laparoscopic nephrectomy (LN) a feasible option. Duarte and colleagues first described LN for Wilms' tumor in 2004 [7]. Subsequently, they published their long-term follow-up on 24 patients [8] and other groups around the world have followed suit with encouraging results [9], [10], [11]. There has also been reference made to the difficulty of lymph node sampling laparoscopically and this is very important for accurate staging [11].

In 2014, SIOP released the Umbrella Protocol, which offered guidance on when LN could be a suitable option, and these were also included in the 2016 Protocol (Table 1) [12], [13]. These were guidelines based on the experience of groups to date and were conservative to respect the oncological principles of open surgery with avoidance of tumor spillage, that is tumors that were relatively small, with a rim of normal renal cortex around them.

LN has been performed at our institution since 2010 prior to the introduction of the SIOP guidelines. The two surgeons performing the surgeries in this series have experience in other laparoscopic tumor resections [14].The aim of our study was to review our series and outcomes for laparoscopic resections for Wilms' tumor and compare indications to SIOP criteria for LN. The hypothesis was that SIOP criteria were conservative and that the indications could be safely extended.