The Effectiveness of Deflux® Treatment for Vesicoureteral Reflux Following Pediatric Renal Transplantation: A Single-Institution Challenging Experience.

PURPOSE: To validate the effectiveness of Deflux® treatment for vesicoureteral reflux (VUR) following pediatric renal transplantation (RT), based on our single-institution experience. METHOD: A retrospective study was conducted using the medical records of pediatric patients who underwent Deflux® treatment for VUR after RT from April 2008 to March 2022. RESULTS: Sixty-eight pediatric patients underwent RT. VUR was subsequently detected in 22 (32 %) of these patients. Seven of the 22 patients (32 %) underwent Deflux® treatment to avoid renal dysfunction due to urinary infection (UTI). The median age at the time of RT was 4 years (range:2-12). All 7 patients had urinary UTIs before Deflux® treatment. The median estimated glomerular filtration rate (eGFR) before Deflux® treatment was 67 ml/min/1.73 m2 (range:42-138 ml/min/1.73 m2). After Deflux® treatment, VUR was downgraded in three cases (43 %). Four patients (57 %) experienced postoperative UTI, two of who underwent a second Deflux® treatment, one underwent submuscular tunnel reconstruction, and the other one experienced UTI without VUR after 1st Deflux® treatment but did not reoccur. All seven patients continued prophylactic medication after Deflux® treatment, without any history of recurrent UTIs during the observation period after treatment (median 37 months [range 7-86 months]). Furthermore, the eGFRs did not significantly decrease after Deflux® treatment (median eGFR 58 ml/min/1.73 m2 [range:33-99 ml/min/1.73 m2], p > 0.1). CONCLUSION: Deflux® treatment for VUR after RT is technically challenging because the new ureteral orifice is ventrally anastomosed at the bladder. We believe our results indicate the possibility of reducing the frequency of UTIs and contributing to preservation of the renal function after RT. TYPE OF STUDY: Retrospective Study. LEVEL OF EVIDENCE: Level III.

Surgical outcome and prognosis of pediatric solid-pseudopapillary neoplasm.

BACKGROUND: The aim of this study was to clarify the characteristics and outcomes of pediatric patients with solid pseudopapillary neoplasms (SPNs) who underwent pancreatectomy. METHODS: Pediatric patients with SPNs who underwent pancreatectomy at our institution between 1995 and 2020 were included in the study. RESULTS: During the period under review, 12 patients underwent pancreatectomy for SPNs (median age: 10 years; range: 6-15 years). The surgical procedures included pancreatoduodenectomy (n = 2; 16.6%), distal pancreatectomy (n = 3; 25%), and enucleation (n = 7; 58.3%). The most common postoperative complication was postoperative pancreatic fistula (n = 6; 50%). Patients who underwent enucleation tended to have higher postoperative complication rates compared with those who underwent other procedures. All patients were alive without recurrence at the end of the study period. CONCLUSIONS: SPN is associated with a good prognosis, regardless of the surgical procedure. If surgeons select enucleation for pediatric SPNs, they should bear in mind that it is associated with a higher complication rate.

Safety and efficacy of multiple tyrosine kinase inhibitors in pediatric/adolescent and young adult patients with relapsed or refractory osteosarcomas: A single-institution retrospective analysis.

BACKGROUND: The prognosis of relapsed or refractory osteosarcoma remains poor. Recent reports have stated that molecular targeting agents, including multiple tyrosine kinase inhibitors (MTKIs), are effective against adult osteosarcoma. To determine the safety and efficacy of MTKI therapy in children, adolescents and young adults (AYAs), we conducted a retrospective study on adverse events and treatment outcomes. METHODS: We retrospectively reviewed the medical records of patients with relapsed or refractory osteosarcoma who received MTKI therapy at the Department of Pediatric Oncology, National Cancer Center Hospital, from December 2013 to May 2021. RESULTS: The study included 31 patients (15 males and 16 females) who received MTKIs, including sorafenib monotherapy (seven patients), sorafenib and everolimus (14 patients), and regorafenib monotherapy (10 patients). Their median age was 17 years (range: 11-22 years). The incidence of treatment-related grade 3 nonhematological adverse events was 14.3% in the sorafenib monotherapy group, 21.4% in the sorafenib with everolimus group, and 20.0% in the regorafenib monotherapy group. No grade 4 nonhematological adverse events were observed. The median progression-free survival (PFS) was 51 days in the sorafenib monotherapy group, 101 days in the sorafenib with everolimus group, and 167 days in the regorafenib monotherapy group. CONCLUSION: The safety profile of MTKI therapies in pediatric and AYA patients was comparable to that in adult patients. MTKI therapies, particularly regorafenib, against pediatric relapsed osteosarcoma can suppress tumor growth and prolong PFS with tolerable adverse events.

Vaginal yolk sac tumor resected by a novel laparo/endoscope-assisted posterior sagittal approach: a case report.

BACKGROUND: Yolk sac tumor (YST) is a germ cell tumor that is generally associated with good prognosis in children. It has been recently reported that vaginal YSTs can be cured using chemotherapy alone. Thus, minimal invasiveness and function preservation are pre-requisites for surgical approaches. Herein, we report a case of vaginal YST that was resected in a function-preserving manner using a unique combination of surgical approaches. CASE PRESENTATION: In a 9-month-old Asian female infant, a vaginal tumor was detected while investigating for vaginal bleeding. The patient was referred to our hospital, and the tumor was diagnosed as a YST after incisional biopsy. Six courses of carboplatin-based chemotherapy were administered. Contrary to the findings in previous reports, the tumor was chemo-resistant and surgical resection was required for the residual tumor. During surgery, we utilized laparoscopic and endoscopic procedures to ensure tumor-free surgical margins at the cervix, rectum, and lateral wall of the vagina. Additionally, the posterior sagittal approach was used to easily resect the tumor, and the vagina was reconstructed leaving only inconspicuous scars in the intergluteal cleft. No complications occurred postoperatively. Pathological examination of the surgical specimen revealed tumor-free surgical margins. The patient received four cycles of intensified chemotherapy before and after the surgery. The patient has been disease-free for 6 months now. CONCLUSIONS: Our combination of laparo/endoscopic and posterior sagittal approach ensured a tumor-free macroscopic surgical margin with easier, cosmetically pleasing vaginal reconstruction, while preserving the anorectal and urinary functions. We believe that this approach could be utilized not only for vaginal YST, but also for any vaginal tumor, especially those arising from the posterior or lateral wall.

Novel mesenchymal stem cell delivery system as targeted therapy against neuroblastoma using the TH-MYCN mouse model.

PURPOSE: Mesenchymal stem cells (MSCs) are reported to migrate toward damaged tissues or tumors. We previously reported the in vivo short-term (1 day) tumor-homing effect of xenogeneic human MSCs (hMSCs) using the TH-MYCN mouse neuroblastoma model (MYCN-TgM). In this study, we analyzed the long-term tumor-homing effect of allogeneic mouse MSCs (mMSCs) and explored the antitumor effect and drug delivery function of mMSCs. METHODS: mMSCs were administered intraperitoneally (i.p.) to MYCN-TgM and traced by an in vivo imaging system (IVIS). We administered green fluorescent protein (GFP)-transduced mMSCs into MYCN-TgM i.p. and examined the cell survival by immunohistochemistry. We also administered interferon beta-transduced mMSCs (mMSCs-IFN-ß) to MYCN-TgM i.p. and measured the concentration of IFN-ß in the tumor and organs by an enzyme-linked immunosorbent assay (ELISA). The survival curves of MYCN-TgM administered every week was analyzed. RESULTS: The IVIS revealed the accumulation of fluorescence was observed in the tumor both in vivo and after excision. Immunohistochemistry using anti-GFP antibody revealed that the mMSCs existed within the tumor until 14 days but not in the organs. The ELISA showed increased concentrations of IFN-ß only in the tumors, with the values gradually diminishing over 14 days. The mMSCs-IFN-ß group survived significantly longer than the control group (p < 0.03), while the mMSCs-alone group did not show a survival advantage. CONCLUSIONS: Allogeneic mMSCs showed a homing ability for mouse neuroblastoma and existed within the tumor for as long as two weeks. This may be a candidate drug delivery vehicle for antitumor agents against neuroblastoma.

Enhanced metastatic growth after local tumor resection in the presence of synchronous metastasis in a mouse allograft model of neuroblastoma.

PURPOSE: We investigated how local tumor resection affects metastatic lesions in neuroblastoma. METHODS: MYCN Tg tumor-derived cells were injected subcutaneously into 129+Ter/SvJcl wild-type mice. First, the frequency of metastasis-bearing mice was investigated immunohistochemically (metastatic ratio) at endpoint or post-injection day (PID) 90. Second, the threshold volume of local tumor in mice bearing microscopic lymph node metastasis (mLNM) was investigated at PID 30. Finally, local tumors were resected after exceeding the threshold. Mice were divided into local tumor resection (Resection) and observation (Observation) groups, and the metastatic ratio and volume of LNM were compared between the groups at endpoint or PID 74. RESULTS: The metastatic ratio without local resection was 88% at PID 78-90. The threshold local tumor volume in the mice with mLNM was 745 mm3 at PID 30, so local tumors were resected after exceeding 700 mm3. The metastatic ratio and LNM volume were significantly greater in the Resection group (n = 16) than in the Observation group (n = 16) (94% vs. 38%, p < 0.001; 2092 ± 2310 vs. 275 ± 218 mm3, p < 0.01; respectively) at PID 50-74. CONCLUSION: Local tumor resection might augment the growth of synchronous microscopic metastases. Our results provide insights into the appropriate timing of local resection for high-risk neuroblastoma.

Surgical intervention and perioperative risk factors of retroperitoneal teratomas in children: a single institution experience.

PURPOSE: Retroperitoneal teratomas (RTs) are rare among germ cell tumors and predominantly occur in infants. RTs are often difficult to manage by perioperative management. In this study, we retrospectively reviewed our series of RTs. METHODS: Seventy patients with germ cell tumors were treated from 1989 to 2015 in our institution. Fourteen patients had RTs (3 boys and 11 girls). The median age at diagnosis was 5.5 months (range 0-64), and three were antenatally diagnosed. RESULTS: All except one patient underwent total tumor excision. They exhibited dense adhesions with major vessels, and ligation of the splenic and gastroduodenal arteries was required in two patients. Injuries of PV and renal artery occurred in two patients. IVC injury in a neonate with a giant mass caused circulatory failure and brain death occurred postoperatively. Other major complications included injury of the diaphragm and bile duct. An infant whose tumor compressed the superior mesenteric artery developed enteritis while waiting for surgery and non-occlusive mesenteric ischemia, resulting in massive intestinal necrosis. The perioperative complication rate was 50 %. CONCLUSION: Surgery for RTs remains challenging, and a preoperative evaluation of the vascular anatomy is crucial due to the high complication rate. Moreover, pre- and intraoperative fluid management is important to avoid any unexpected fatalities.