Preoperative Wilms tumor rupture in children

According to the guidelines of International Society of Pediatric Oncology (SIOP) and National Wilms Tumor Study (NWTS), Wilms tumor with preoperative rupture should be classified as at least stage III. Few clinical reports can be found about preoperative Wilms tumor rupture. The purpose of this study was to investigate our experience on the diagnosis, treatment and prognosis of preoperative Wilms tumor rupture.

Patients with Wilms tumor who underwent treatment according to the NWTS or SIOP protocol from January 2008 to September 2017 in Beijing Children's Hospital were reviewed retrospectively. The clinical signs of preoperative tumor rupture were acute abdominal pain, and/or fall of hemoglobin. The radiologic signs of preoperative tumor rupture are as follows: (1) retroperitoneal and/or intraperitoneal effusion; (2) acute hemorrhage located in the sub-capsular and/or perirenal space; (3) tumor fracture communicating with peritoneal effusion; (4) bloody ascites. Patients with clinical and radiologic signs of preoperative tumor rupture were selected. Patients having radiologic signs without clinical symptoms were also selected. The clinical data, treatments and outcomes were analyzed. Meanwhile, patients without preoperative Wilms tumor rupture during the same period were collected and analyzed.

565 Patients with Wilms tumor were registered in our hospital. Of these patients, 45 patients were diagnosed with preoperative ruptured Wilms tumor. All preoperative rupture were confirmed at surgery. Spontaneous tumor rupture occurred in 41 patients, the other 4 patients had traumatic history. Of the 45 patients, 41 were classified as stage III, 3 patients with pulmonary metastases were classified as stage IV, and one patient with bilateral tumors were classified as stage V. Of these patients with preoperative tumor rupture at stage III, 30 patients had clinical and radiologic signs of tumor rupture, the other 11 patients had radiologic signs without clinical symptoms. Among the 41 patients at stage III, 13 patients had immediate surgery without preoperative chemotherapy (immediate group), and 28 patients had delayed surgery after preoperative chemotherapy (delayed group). In immediate group, 12 patients had localized rupture, 1 patient underwent emergency surgery because of continuous bleeding. In delayed group, 4 had inferior vena cava tumor embolus (1 thrombus extended to inferior vena cava behind the liver, three thrombi got to the right atrium), 4 crossed the midline with large tumors, 20 had extensive rupture without localization. In immediate group, tumor recurrence and metastasis developed in 2 patients, and no death occurred. In the delayed group, tumor recurrence and metastasis developed in 8 patients, and 7 patients died. During the same period, 41 patients were classified as stage III without preoperative rupture. In the non-ruptured group, tumor recurrence and metastasis developed in 3 patients, and 4 patients died. The median survival time in the ruptured group (both immediate group and delayed group) and non-ruptured group were (85.1 ± 7.5) and (110.3 ± 5.6) months, and the 3-year cumulative survival rates were 75.1% and 89.6%, respectively. The overall survival rate between the ruptured and non-ruptured groups showed no statistic difference (P = 0.256). However, there was significant difference in recurrence or metastasis rate between the ruptured and non-ruptured groups (24.4% vs 7.3%; P = 0.031).

Contrast-enhanced computed tomography (CT) and ultrasonography (US) are of major value in the diagnosis of preoperative tumor rupture, and immediate surgery or delayed surgery are available therapeutic methods. The treatment plan was based on patients' general conditions, tumor size, position and impairment degree of tumor rupture, extent of invasion and experience of a multidisciplinary team (including surgeon and anesthesiologists). In our experience, for ruptured preoperative tumor diagnosed with stage III, the criteria for immediate surgery are as follows: tumor not acrossing the midline, tumor without inferior vena cava thrombus, localized rupture, being capable of complete resection. Selection criteria for delayed surgery after preoperative chemotherapy are as follows: large tumors, long inferior vena cava tumor thrombus, tumors infiltrating to surrounding organs, unlocalized rupture, tumors can not being resected completely. Additionally, patients with preoperative Wilms tumor rupture had an increased risk of postoperative recurrence or metastasis.