Surgical strategies for unresectable hepatoblastomas

Surgical management of liver tumors

Two percent of pediatric malignancies arise primarily in the liver; roughly 60% of these cancers are hepatoblastoma (HB). Despite the rarity of these cases, international collaborative efforts have led to the consistent histological classification and staging systems, which facilitate ongoing clinical trials. Other primary liver malignancies seen in children include hepatocellular carcinoma (HCC) with or without underlying liver disease, fibrolamellar carcinoma (FLC), undifferentiated embryonal sarcoma of the liver (UESL), and hepatocellular neoplasm not otherwise specified (HCN-NOS). This review describes principles of surgical management of malignant pediatric primary liver tumors, within the context of comprehensive multidisciplinary care.

Central Liver Segments Resections vs Extended Hepatectomies in Children: Single-Center Experience

BACKGROUND

Central liver segments resection (CLSR) still is not widely used in pediatric surgery due to its technical difficulty, whereas this procedure is widely spread as a parenchyma sparing approach of centrally located liver tumors in adults. The aim of this study is to analyze the outcomes of CLSR in comparison with extended hepatectomy (EH) in children with different liver tumors.

METHODS

A single-center retrospective analysis of patients who received CLSR (n = 14) and EH (n = 44) from June 2017 to December 2023 was applied. Patient's characteristics, preoperative, intra- and postoperative data were compared between 2 groups.

RESULTS

Preoperative CT-volumetry showed that future liver remnant volume was higher in CLSR group compared to EH (FLR-V; (54 ± 29 (40-91) % vs 40 ± 12 (17-73) %, p = 0.016). The intraoperative blood loss (200 [90-1150] (20-3000) ml vs 100 [30-275] (10-9000) ml, p = 0.088) and transfusion volume (310 [85-590] (0-1860) ml vs 150 [0-310] (0-4770) ml, p = 0.484) were similar in both groups, while operation time was longer in CLSR group (420 [320-595] (145-785) min vs 280 [203-390] (125-710) min), p = 0.011). There was no difference in biliary leakage (3 (21.4 %) vs 12 (27.3 %); p = 0.479), other complications (4 (28.6 %) vs 5 (11.4 %), p = 0.198) and complications ≥ IIIb by Clavien-Dindo (2 (14.3 %) vs 8 (18.2 %), p = 0.385) postoperatively.

CONCLUSION

CLSRs allow to preserve more healthy liver parenchyma compared to EH with similar intraoperative and postoperative outcomes. «Extended mesohepatectomy» allows to achieve R0 resection when central liver tumor extends on the left lateral and/or right posterior section.

TYPE OF STUDY

Retrospective Comparative Study (Level of Evidence III).

Advances in the conventional clinical treatment for hepatoblastoma and therapeutic innovation

Background

Hepatoblastoma (HB) is a rare malignancy usually occurring in children under 3 years old. With advancements in surgical techniques and molecular biology, new treatments have been developed.

Data resources

The recent literatures on new treatments, molecular mechanisms and clinical trials for HB were searched and reviewed.

Results

Surgical resection remains the main option for treatment of HB. Although complete resection is recommended, a resection with microscopical positive margins (R1) may have similar 5-year overall survival and 5-year event-free survival (EFS) rates after cisplatin chemotherapy and the control of metastasis, as only once described so far. Indocyanine green-guided surgery can help achieve precise resection. Additionally, associating liver partition and portal vein ligation for staged hepatectomy can rapidly increase future liver remnant volume compared with portal vein ligation or embolization. Cisplatin-containing chemotherapies slightly differ among the guidelines from the International Childhood Liver Tumors Strategy Group (SIOPEL), Children’s Oncology Group (COG) and Chinese Anti-Cancer Association Pediatric Committee (CCCG), and the 3-year EFS rate of patients in SIOPEL and CCCG studies was recently shown to be higher than that in COG studies. Liver transplantation is an option for patients with unresectable HB, and successful cases of autologous liver transplantation have been reported. In addition, effective inhibitors of important targets, such as the mTOR (mammalian target of rapamycin) inhibitor rapamycin, β-catenin inhibitor celecoxib and EpCAM (epithelial cell adhesion molecule) inhibitor catumaxomab, have been demonstrated to reduce the activity of HB cells and to control metastasis in experimental research and clinical trials.

Conclusion

These advances in surgical and medical treatment provide better outcomes for children with HB, and identifying novel targets may lead to the development of future targeted therapies and immunotherapies.

Surgical management of locally-advanced and metastatic hepatoblastoma

Advanced stage hepatoblastoma, including both locally advanced primary tumors as well as metastatic disease, poses unique clinical challenges. Despite substantial advances in chemotherapeutics, surgical extirpation remains the mainstay of cure for this tumor. Locally advanced tumors that involve multiple hepatic lobes and/or invade significant vascular structures can be managed either by complex hepatic resections or liver transplantation. We review the indications, roles, and outcomes of these surgical approaches as well as those for the resection of pulmonary metastases.

Impact of microscopically margin-positive resection on survival in children with hepatoblastoma after hepatectomy: a retrospective cohort study

BACKGROUND

Impact of R1 (microscopically margin-positive) resection on survival of patients with hepatoblastoma (HB) remains debatable. This study aimed to compare the long-term outcomes of R0 (microscopically margin-negative) and R1 resection for HB in children after hepatectomy.

METHODS

We retrospectively reviewed files of children with HB who underwent resection at our institution between September 1, 2005, and November 30, 2017. Survival analyses and prognostic factors were evaluated using Kaplan-Meier curves and Cox regression models.

RESULTS

Of 259 patients, 218 (84.2%) underwent R0 and 41 (15.8%) R1 resection. After adjusting for confounding factors, R1 resection demonstrated non-significantly lower overall survival (OS: hazard ratio [HR] = 0.75; 95% CI 0.34-1.64) and shorter event-free survival (EFS: HR = 0.97; 95% CI 0.53-1.78) rates than R0 resection. However, stratified analysis showed significantly increased risk of poor OS and EFS in patients with metastasis and mixed epithelial/mesenchymal pathologic subtype in R1 compared with R0 resection (P values for interactions < 0.05). There was no significant difference between R0 resection with metastasis and R1 resection with metastasis in the incidence of local recurrence (P = 0.494); however, a significant difference in the incidence of local recurrence was seen between R0 and R1 resection for subgroups with mixed pathologic subtypes (P = 0.035).

CONCLUSIONS

With effective chemotherapy, microscopic margin status may not be associated with survival outcome in children with HB undergoing hepatectomy. However, stratified analysis showed that R1 resection might be associated with decreased survival in children with mixed epithelial/mesenchymal HB, compared with R0 resection, and not affect survival outcomes in those with an epithelial subtype and without metastasis.

Error traps and culture of safety in pediatric surgical oncology

This article reviews technical issues to improve surgical safety and avoid surgical errors in pediatric surgical oncology, particularly in the three most common extracranial solid tumors: neuroblastoma, hepatoblastoma and Wilms tumor. The use of adjuvant chemotherapy - when indicated - the use of tumor specific classifications, adequate surgical planning, that may include the use of 3D printable models, improved surgical instruments and technology, and following surgical guidelines, would result in avoiding error, increased safety, and therefore in improved surgical outcomes.

Navigation surgery using indocyanine green fluorescent imaging for hepatoblastoma patients

BACKGROUND

Technology for detecting liver tumors and identifying the bile ducts using indocyanine green (ICG) has recently been developed. However, the usefulness and limitations of ICG navigation surgery for hepatoblastoma (HB) have not been fully clarified. We herein report our experiences with surgical navigation using ICG for in HB patients.

METHODS

In 5 HB patients, 10 ICG navigation surgeries were performed using a 10-mm infrared fluorescence imaging scope after the injection of 0.5 mg/kg ICG intravenously. The surgical and clinical features were collected retrospectively.

RESULTS

Navigation surgery using ICG was performed for primary liver tumors in 4 cases, and the timing of ICG injection was 90.5 ± 33.7 h before the operation. All tumors exhibited intense fluorescence from the liver surface. ICG navigation for the primary liver tumor was useful for detecting the residual tumor at the stump and invasion to the diaphragm during surgery. Six lung surgeries using ICG navigation were performed. The timing of ICG injection was 21.8 ± 3.4 h before the operation. The size of the metastatic tumor was 7.4 ± 4.1 mm (1.2-15 mm). Of 11 metastatic tumors detected by computed tomography (CT), 10-including the smallest tumor (1.2 mm)-were able to be detected by ICG from the lung surface. The depth of the 10 ICG-positive tumors from the lung surface was 0.9 ± 1.9 mm (0-6 mm), and the depth of the single ICG-negative tumor was 12 mm. One lesion not detected by CT showed ICG false positivity.

CONCLUSION

Navigation surgery using ICG for patients with HB was useful for identifying tumors and confirming complete resection. However, in ICG navigation surgery, we must be aware of the limitations with regard to the tumor size and the depth from the surface.

Long-term outcomes of liver transplantation for hepatoblastoma: A single-center 14-year experience

HB is the most common primary liver tumor in children. Complete tumor excision, either by partial resection or by total hepatectomy and liver transplantation, in combination with chemotherapy provides the best chance for cure. We performed a retrospective analysis of patients who underwent liver transplantation for HB and herein present our 14-year single-institution experience. Twenty-five patients underwent liver transplantation for HB at a median age of 26 months (IQR: 15-44). Graft survival was 96%, 87%, and 80% at 1, 3, and 5 years, respectively. There were four patient deaths, three of them due to disease recurrence within the first year post-transplant. Ten-year overall survival was 84%. Three recipients initially presented with pulmonary metastases and underwent resection of metastatic disease, of which two are alive at 3.9 years. Of three patients who underwent salvage transplants, two are alive at 1.5 years after transplant. Non-survivors were associated with lower median alpha fetoprotein value at presentation compared to survivors (21 707 vs 343 214; P = .04). In conclusion, the overall long-term outcome of primary liver transplantation for HB is excellent. Tumor recurrence was the highest contributor to mortality. Even patients with completely treated pulmonary metastases prior to transplant demonstrated a favorable survival.

Liver transplantation for hepatobiliary malignancies: a new era of "Transplant Oncology" has begun

The indications of liver transplantation for hepatobiliary malignancies have been carefully expanded in a stepwise fashion, despite the fundamental limitations in oncological, immunological, and technical aspects. A new era of "Transplant Oncology," the fusion of transplant surgery and surgical oncology, has begun, and we stand at the dawn of a paradigm shift in multidisciplinary cancer treatment. For hepatocellular carcinoma, new strategies have been undertaken to select recipients based on biological and dynamic markers instead of conventional morphological and static parameters, opening the doors for a more deliberate expansion of the Milan criteria and locoregional therapies before liver transplantation. Neoadjuvant chemoradiation therapy followed by liver transplantation for unresectable perihilar cholangiocarcinoma developed by the Mayo Clinic provided excellent outcomes in a US multicenter study; however, the surgical indications are not necessarily universal and await international validation. Similarly, an aggressive multidisciplinary approach has been applied for other tumors, including intrahepatic cholangiocarcinoma, hepatoblastoma, liver metastases from colorectal and neuroendocrine primary and gastrointestinal stromal tumors as well as rare tumors, such as hepatic undifferentiated embryonal sarcoma and infantile choriocarcinoma. In conclusion, liver transplantation is an important option for hepatobiliary malignancies; however, prospective studies are urgently needed to ensure the appropriate patient selection, organ allocation and living donation policies, and administration of antineoplastic immunosuppression.

Indications, limitations and maneuvers to enable extended hepatectomy: Current trends

The liver is a solid organ with a wide variety of primary benign or malignant tumors as well as metastatic lesions. Surgical resection of these tumors remains the only curative modality. Several limitations, however, do not allow the performance of these operations. This review evaluates the indications and limitations regarding these extended hepatic resections, as well as describing all the manipulations that increase the candidates for such operations. A thorough review of the literature was performed in order to define indications for extended hepatectomy, as well as to present all methods that contribute to increasing the volume of the future remnant liver. The role of portal vein ligation, portal vein embolization, two-stage hepatectomy, and in situ liver transection are evaluated in the setting of indications and results. Extended hepatectomies are a necessity due to oncological reasons. All methods developed in order to increase the volume of the remnant liver are safe and efficient. in situ liver transection is a novel and revolutionary two-step procedure for extended hepatic resections. Further clinical studies are required to estimate long-term results and the oncological basis of this technique.

Management of hepatoblastoma: an update

PURPOSE OF REVIEW

To summarize the current standards and guidelines for the diagnosis and management of hepatoblastoma, a rare pediatric liver tumor.

RECENT FINDINGS

Hepatoblastoma is the most common malignant liver tumor in childhood. International collaborative efforts have led to uniform implementation of the pretreatment extent of disease (PRETEXT) staging system as a means to establish consensus classification and assess upfront resectability. Additionally, current histopathological classification, in light of more advanced molecular profiling and immunohistochemical techniques and integration of tumor biomarkers into risk stratification, is reviewed. Multimodal therapy is composed of chemotherapy and surgical intervention. Achievement of complete surgical resection plays a key role in successful treatment for hepatoblastoma. Overall, outcomes have greatly improved over the past four decades because of advances in chemotherapeutic agents and administration protocols as well as innovations of surgical approach, including the use of vascular exclusion, ultrasonic dissection techniques, and liver transplantation. Challenges remain in management of high-risk patients as well as patients with recurrent or metastatic disease.

SUMMARY

Eventually, a more individualized approach to treating the different types of the heterogeneous spectrum of hepatoblastoma, in terms of different chemotherapeutic protocols and timing as well as type and extent of surgery, may become the basis of successful treatment in the more complex or advanced types of hepatoblastoma.

Current status of the organ replacement approach for malignancies and an overture for organ bioengineering and regenerative medicine

Significant achievements in the organ replacement approach for malignancies over the last 2 decades opened new horizons, and the age of "Transplant Oncology" has dawned. The indications of liver transplantation for malignancies have been carefully expanded by a strict patient selection to assure comparable outcomes with non-malignant diseases. Currently, the Milan criteria, gold standard for hepatocellular carcinoma, are being challenged by high-volume centers worldwide. Neoadjuvant chemoradiation therapy and liver transplantation for unresectable hilar cholangiocarcinoma has been successful in specialized institutions. For other primary and metastatic liver tumors, clinical evidence to establish standardized criteria is lacking. Intestinal and multivisceral transplantation is an option for low-grade neoplasms deemed unresectable by conventional surgery. However, the procedure itself is in the adolescent stage. Solid organ transplantation for malignancies inevitably suffers from "triple distress," i.e., oncological, immunological, and technical. Organ bioengineering and regenerative medicine should serve as the "triple threat" therapy and revolutionize "Transplant Oncology."

Morbidity and mortality associated with liver resections for primary malignancies in children

PURPOSE

Liver resection (LR) is a high-risk procedure with limited data in the pediatric surgical literature regarding short-term outcomes. Our aim was to characterize the patient population and short-term outcomes for children undergoing LR for malignancy.

METHODS

We studied 126 inpatient admissions for children ≤20 years of age undergoing LR in 2009 using the Kids' Inpatient Database. Patients had a principal diagnosis of a primary hepatic malignancy and LR listed as one of the first five procedures. Transplantations were excluded. Complications were defined by ICD-9 codes. High-volume centers performed at least 5 LR.

RESULTS

The mean age was 5.83 years. The morbidity and mortality rates were 30.7 and 3.7%, respectively. The most common causes of morbidity were digestive system complications (7.4%), anemia (7.3%), and respiratory complications (3.8%). 43.9% received a blood product transfusion. The average length of stay was 10.04 days. When compared to low-volume centers, high-volume centers increased the likelihood of a complication fourfold (P = 0.011) but had 0% mortality (P = 0.089).

CONCLUSION

LR remains a procedure fraught with multiple complications and a significant mortality rate. High-volume centers have a fourfold increase in likelihood of complications compared to low-volume centers and may be related to extent of hepatic resection.

Current therapeutic strategies for childhood hepatic tumors: surgical and interventional treatments for hepatoblastoma

Surgery is the mainstay of multimodal treatment for hepatoblastomas. Among the various staging systems used, PRETEXT is currently adopted in all major study groups worldwide as a common pretreatment staging system. Although variations of treatment strategies among study groups exist, the majority of hepatoblastoma cases currently undergo preoperative chemotherapy. It is therefore critical to determine the optimal surgical treatment during the initial courses of chemotherapy. Patients with PRETEXT IV tumors, multifocal tumors and tumors invading major vessels of the liver are candidates for liver transplantation. Liver transplantation requires preparation in advance, and consultation to a liver expertise team must take place no later than after two cycles of chemotherapy. The existence of pulmonary metastasis is a predictor of poor prognosis of the patient. Surgery for pulmonary nodules should be considered for those patients remaining positive after cycles of chemotherapy. A considerable number of patients have been reported to achieve long-term survival after resecting pulmonary metastasis. The existence of pulmonary metastasis at diagnosis is no longer a contraindication for liver transplantation, provided that the pulmonary nodules are eliminated by chemotherapy or by metastasectomy. Transcatheter arterial chemoembolization (TACE) is a useful tool for the local control of hepatoblastomas, although there are very few reports statistically supporting the significant advantage of this treatment modality. Based on individual cases, TACE could be beneficial in maximizing the anti-tumor effect with less toxic side effects.

A cisplatin plus pirarubicin-based JPLT2 chemotherapy for hepatoblastoma: experience and future of the Japanese Study Group for Pediatric Liver Tumor (JPLT)

INTRODUCTION

The Japanese Study Group for Pediatric Liver Tumor (JPLT) has conducted cooperative treatment studies on hepatoblastoma (HBL) since 1991. The JPLT2 protocol was launched in 1999 to evaluate the efficacy of cisplatin/pirarubicin (CITA) under risk stratification. European and North American groups showed the improvement of HBL patients by pre- and postoperative chemotherapeutic regimens. Therefore, we evaluated the results of JPLT study and considered the future aspect of JPLT.

METHODS

A total of 389 children with malignant hepatic tumors were enrolled in JPLT-2 until 2010. Data from 331 HBL cases were analyzed.

RESULTS AND DICUSSION

Of the 331 patients enrolled, their 5-year overall survival and event-free survival rates were 83.3 and 68.0%, respectively. While outcomes of standard-risk cases (tumors involving 3 or fewer sectors of the liver) were excellent, those of high-risk cases (tumors involving 4 sectors of the liver or with distant metastases) remained poor. For 26 high-risk or relapse/refractory HBL cases, high-dose chemotherapy (HDC) with stem cell transplantation (SCT) was carried out. Among them, 6 of 12 relapse or refractory cases died. Compared with other regimens, the CITA regimen achieved similar or superior rates of survival among children with standard-risk HBL, while HDC with SCT was not effective in patients with high-risk HBL. Presently, a global Children's Hepatic Tumor International Consortium (CHIC) project is ongoing, with a focus on international cooperation and risk stratification in the field of rare liver cancers in children. More promising strategies, including liver transplantation and new targeting drugs under global risk stratification, are being proposed.