Resection and reconstruction of the inferior vena cava for neoplasms

Single-stage inferior vena caval intravenous leiomyomatosis excision

Intravascular tumour extension can occur in many different types of cancer. Those with the highest tendency include renal cell carcinoma, adrenal cortical carcinoma and hepatocellular carcinoma. Inferior vena cava (IVC) tumour thrombus in gynaecological malignancy is rarely reported. We present a report on a female patient with extensive IVC tumour thrombus (intravenous leiomyomatosis) with concurrent intrauterine leiomyomatosis. She underwent a single-stage procedure, involving laparotomy and a sternotomy to remove her pelvic tumour, as well as the intracaval and intracardiac thrombus. The clinical presentation and management of this rare tumour will be detailed in this case report.

Resection of retroperitoneal tumors with inferior vena cava involvement without caval reconstruction

BACKGROUND AND OBJECTIVES

Retroperitoneal tumors with involvement of the inferior vena cava (IVC) often require resection of the IVC to achieve complete tumor removal. This study evaluates the safety and efficacy of IVC ligation without caval reconstruction.

METHODS

A retrospective chart review of patients who underwent IVC ligation (IVC-Ligation) and IVC resection with reconstruction (IVC-Reconstruction) at our institution between May 2004 and April 2021 was performed. Outcomes from the two surgical techniques were compared via univariate analysis using the Kruskal-Wallis test for continuous variables and Fisher's exact test for categorical variables.

RESULTS

Forty-nine IVC-Ligation and six IVC-Reconstruction surgeries were identified. There were no differences in baseline demographics, tumor characteristics, complication rates, postoperative morbidity, or overall 5-year survival between groups. IVC-Reconstruction patients were more likely to require intensive care unit admission (83% vs. 33%; p = 0.0257) and the IVC-Ligation cohort had a tendency to present with nondebilitating postoperative lymphedema (35% vs. 0%; p = 0.1615), which resolved for most patients.

CONCLUSIONS

IVC-Ligation is a viable surgical option for select patients presenting with retroperitoneal tumors with IVC involvement and provides acceptable short- and medium-term outcomes.

Infra-hepatic caval resection en bloc with right nephrectomy followed by caval reconstruction for locally advanced caval leiomyosarcoma: A case report and literature review

Retroperitoneal sarcomas often require complex surgical procedures in order to achieve complete resection; in such cases both vascular and visceral resections are needed. When it comes to the need for vascular reconstruction, the type of graft as well as the type of reconstructive process are chosen according to the length and location of the resected segment. Meanwhile, depending on the location of the resected segment, other vascular reconstructions may be needed such as the reimplantation of the renal veins. However, in certain cases, this reimplantation is not mandatory, an adequate renal outflow being reported through the collateral network at this level. We present the case of a 43-year-old patient diagnosed with a large retroperitoneal sarcoma originating from the cava vein invading the right kidney. Resection of the tumor was performed en bloc with caval resection and right nephrectomy, without reimplantation of the left renal vein at the level of the graft. Extended visceral and vascular resections might be needed in order to achieve complete resection of inferior cava vein sarcomas; re-implantation of the left renal vein being not mandatory if rich collateral circulation is present.

Vascular Involvements in Cholangiocarcinoma: Tips and Tricks

Simple Summary

Cholangiocarcinoma (CCA) is the second most common liver primary malignancy and its gold-standard treatment is surgery. Unfortunately, CCA is seldom amenable to curative resection due to late-stage diagnosis and frequent major vascular invasion. Major vascular invasion has historically been considered a contraindication to resection, but lately aggressive surgeries for CCA with vascular involvement have been shown to improve outcomes. The purpose of this review is to provide a comprehensive and up to date summary of the strategies for CCA resection, focusing on the surgical techniques and results of complex procedures with tumour vascular involvements. The current review shows that satisfactory results can be achieved in patients with CCA and tumoral vascular invasion by aggressive surgical resection and challenging vascular reconstruction, ensuring a meticulous evaluation of patients in a multidisciplinary setting by experienced hepatobiliary surgeons.

Abstract

Cholangiocarcinoma (CCA) is an aggressive malignancy of the biliary tract. To date, surgical treatment remains the only hope for definitive cure of CCA patients. Involvement of major vascular structures was traditionally considered a contraindication for resection. Nowadays, selected cases of CCA with vascular involvement can be successfully approached. Intrahepatic CCA often involves the major hepatic veins or the inferior vena cava and might necessitate complete vascular exclusion, in situ hypothermic perfusion, ex situ surgery and reconstruction with autologous, heterologous or synthetic grafts. Hilar CCA more frequently involves the portal vein and hepatic artery. Resection and reconstruction of the portal vein is now considered a relatively safe and beneficial technique, and it is accepted as a standard option either with direct anastomosis or jump grafts. However, hepatic artery resection remains controversial; despite accumulating positive reports, the procedure remains technically challenging with increased rates of morbidity. When arterial reconstruction is not possible, arterio-portal shunting may offer salvage, while sometimes an efficient collateral system could bypass the need for arterial reconstructions. Keys to achieve success are represented by accurate selection of patients in high-volume referral centres, adequate technical skills and eclectic knowledge of the various possibilities for vascular reconstruction.

Single-Centre Experience of Supra-Renal Vena Cava Resection and Reconstruction

BACKGROUND

Tumours involving the supra-renal segment of IVC have dismal prognosis if left untreated. Currently, aggressive surgical management is the only potentially curative treatment but is associated with relatively high morbidity and mortality. This study aims to evaluate perioperative factors, associated with adverse postoperative outcomes, based on the perioperative characteristics and type of IVC reconstruction.

METHODS

We identified 44 consecutive patients, who underwent supra-renal IVC resection with a mean age of 57.3 years. Isolated resection of IVC was performed in four patients, concomitant liver resection was performed in 27 patients and other associated resection in 13 patients. Total vascular exclusion was applied in 21 patients, isolated IVC occlusion in 11 patients. Neither venovenous bypass (VVB) nor hypothermic perfusion was used in any of the cases.

RESULTS

The mean operative time was 205 min (150-324 min) and the mean estimated blood loss was 755 ml (230-4500 ml). Overall morbidity was 59% and major complications (Dindo-Clavien ≥ III) occurred in 11 patients (25%). The 90-day mortality was 11% (5pts). Intraoperative haemotransfusion was significantly associated with postoperative general complications (p < 0,001). With a mean follow-up of 26.2 months, the actuarial 1-, 3- and 5-year survival is 69%, 34%, and 16%, respectively.

CONCLUSIONS

IVC resection and reconstruction in the aspect of aggressive surgical management of malignant disease confers a survival advantage in patients, often considered unresectable. When performed in experienced centres it is associated with acceptable morbidity and mortality.

Inferior Vena Cava and Venous Outflow Reconstruction in Living Donor Liver Transplantation in Children: A Single-Center Retrospective Study and Literature Review

Background

In this report, we present technical problems and solutions used in the reconstruction of the inferior vena cava and graft venous outflow during living donor liver transplantation (LDLT) in children.

Material/Methods

In 65 grafts out of 379 liver transplantations from living donors, reconstruction of multiple hepatic venous branches and/or IVC was necessary. In 4 cases, cryopreserved deceased donor venous grafts were used for the reconstruction of the IVC and/or HV.

Results

Follow-up ranged from 2 months to 17.8 years (median 7.2 years). In 4 children, liver re-transplantation was required for a reason not related to venous outflow (biliary complications in 3 patients, graft insufficiency caused by small-for-size syndrome). Two patients died: 1 due to tumor recurrence and 1 due to multi-organ failure. Fifty-nine patients are alive with good liver function. One patient (1.5%) after deceased donor venous graft reconstruction showed symptoms of venous outflow obstruction, which was successfully treated with endovascular balloon angioplasty and stent placement. The remaining 59 transplanted patients do not show any signs of venous outflow obstruction.

Conclusions

In most cases, the reconstruction of multiple hepatic veins of living donor allografts can successfully be done with local venoplasty, while using cold-stored vein grafts may be helpful in selected cases of LDLT.

Current trends in vena cava reconstructive techniques with major liver resection: a systematic review

PURPOSE

Historically, invasion of the inferior vena cava (IVC) represented advanced and often unresectable hepatic disease. With surgical and anesthetic innovations, IVC resection and reconstruction have become feasible in selected patients. This review assesses technical variations in reconstructive techniques and post-operative management.

METHODS

A comprehensive literature search was performed according to PRISMA. Inclusion criteria were (i) peer-reviewed articles in English; (ii) at least three cases; (iii) hepatic IVC resection and reconstruction (January 2015-March 2020). Primary outcomes were reconstructive technique, anti-thrombotic regimen, post-operative IVC patency, and infection. Secondary outcomes included post-operative complications and malignant disease survival.

RESULTS

Fourteen articles were included allowing for investigation of 351 individual patients. Analysis demonstrated significant heterogeneity in surgical reconstructive technique, anti-thrombotic management, and post-operative monitoring of patency. There was increased utilization of ex vivo approaches and decreased use of venovenous bypass compared with previously published reviews.

CONCLUSION

This review of literature published between 2015 and 2020 reveals persistent heterogeneity of hepatic IVC reconstructive techniques and peri-operative management. Increased utilization of ex vivo approaches and decreased use of venovenous bypass point towards improved operative techniques, peri-operative management, and anesthesia. In order to gain evidence for consensus on management, a registry would be beneficial.

Perioperative Outcome of Suprarenal Resection of Vena Cava Without Reconstruction in Urologic Malignancies: A Case Series and Review of the Literature

OBJECTIVE

To describe the feasibility and perioperative outcome of suprarenal resection of inferior vena cava (IVC) in urologic neoplasms without reconstruction.

METHODS

We retrospectively reviewed the patients who underwent suprarenal resection of IVC without reconstruction for urologic neoplasms in our institution between September 2010 and October 2019. Patients' demographic, clinical, radiologic, and 90-day perioperative complications were recorded.

RESULTS

Twenty-eight (79% male) patients with a median age of 59 (25-75) years were included in the study. Twenty-five (89%) of patients had renal cell carcinoma, 1 had renal leiomyosarcoma, and 2 had metastatic testicular teratoma. Twenty-two patients had Mayo level 3 thrombus, 3 had level 2, and 3 had level 4. The mean radiologic thrombus length was 12.6 cm. Eleven patients had radiologic bland thrombosis in the infrarenal IVC. Twenty-seven patients underwent open, and 1 robotic surgery. The median operating time was 411 (range 240-808) minutes, median blood loss was 3750 cc, and all but 1 patient received perioperative transfusion (median 11 units of packed red blood cells). Median hospital stay was 5 (3-50) days. Ninety-day complication rate was 35% (Clavien-Dindo grade I/II and III/IV were 21% and 14%, respectively). Four patients (14%) developed transient nondisabling leg edema. The 90-day mortality rate was 7%.

CONCLUSION

Suprarenal inferior vena cava resection without reconstruction is feasible, yet high-risk operation that should be performed in experienced centers in selected patients with urologic malignancies.

Inferior Vena Cava Repair Using Diaphragm in Animal Model

BACKGROUND

Repair and reconstruction of the vena cava with an autologous vein requires multiple incisions. Prosthetic material is linked with an increased risk of infection and thrombosis. Therefore in this study, we created an animal model of vena cava repair using the diaphragm. The objective of this study is to assess the feasibility and outcomes of using diaphragm for the repair and replacement of the inferior vena cava (IVC) after resection of a part of the infrarenal IVC in an animal model, as it may be encountered in trauma patients and extensive tumors of retroperitoneum.

METHODS

Five healthy dogs of both sexes were prepared. After general anesthesia and laparotomy, a 1 cm width with 4 cm length defect was arranged on anterior aspect of the infrarenal IVC, subsequently, the anterior aspect of the right diaphragm with 1 cm width and 4 cm length was resected and was anastomosed to cover the defect of the IVC as a patch graft, with the pleural side of the diaphragm facing the luminal aspect and the peritoneal side on the outside. The observation period was 6 weeks.

RESULTS

All of the IVCs were macroscopically patent without thrombosis and stenosis. Pathologic assay revealed complete endothelialization of diaphragm. One dog died at the third night of operation without distinct reason.

CONCLUSIONS

The diaphragm is an accessible and safe option in the repair and reconstruction of IVC particularly when restrictions exist for the use of prosthetic material in a contaminated space of the abdomen.

Inferior Vena Cava Resection and Reconstruction with Bovine Pericardium for Renal Cell Carcinoma: Complications and Outcomes

OBJECTIVES

To assess the postoperative complication rate and overall survival when bovine pericardium is used as graft material for inferior vena cava (IVC) reconstructions in patients with renal cell carcinoma (RCC). The ideal graft material is yet to be established, with synthetic grafts widely studied and used in the current literature.

METHODS

We performed a retrospective cohort analysis of consecutive patients who underwent IVC reconstructions as part of resection for RCC, using bovine pericardium as either a patch repair or tubular interposition graft.

RESULTS

A total of 15 patients underwent resection with IVC reconstruction between 2010 and 2018. Nine patients had tubular interposition grafts and 6 had patch repairs. Three patients had Clavien-Dindo grade 3 or higher short-term complications. There was no difference in Comprehensive Complications Index between those who had interposition grafts and patch repairs. Two patients had a long-term graft-associated thrombus requiring temporary anticoagulation. Overall survival was 46.5 months (95% confidence interval [CI] 36.9-56.1). There were no perioperative deaths. All long-term deaths were due to disease progression.

CONCLUSION

Reconstruction of the IVC with a bovine pericardium graft is safe in experienced centers. Bovine pericardium could be considered as the material of choice, given its safety in the immediate postoperative period, ease of use, and patency without routine long-term anticoagulation. Advanced surgical management leads to good overall survival in this cohort with high tumor burden.

One-step reconstruction of IVC and right hepatic vein using reversed auto IVC and left renal vein graft

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The left liver lobe was resected including the tumor and IVC ex vivo, and the right hepatic vein were reconstructed using the reversed patient’s left renal vein (LRV) and IVC graft.

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The patient’s right liver lobe with the reversed LRV/IVC graft was transplanted back into the patient using a partial liver transplant technique.

Introduction

A malignant tumor invading the inferior vena cava (IVC) and concomitant with 3 hepatic venous involvement still remains surgical therapeutic challenge.

Presentation of case

A 79-year-old male presented with liver dysfunction and was eventually diagnosed with an intrahepatic huge IHCC originating at the level of confluence of 3 hepatic veins to the IVC, extending to the right hepatic vein (HV). Under extracorporeal circulation, the liver with the IVC, portal vein, hepatic artery and common bile duct were removed en bloc. In the back table, the left liver lobe was resected including the tumor and IVC, and the right HV was reconstructed using the patient’s reversed left renal vein (LRV) and IVC graft. Subsequently, the patient’s right liver lobe with the reversed LRV/IVC graft was transplanted back into the patient using a partial liver transplant technique. Liver enzymes gradually came down to the value within normal range on postoperative day 13 with the patency of the right HV. However, the patient expired on POD 16 because of sudden septic complications.

Discussion

This technique could be one of the options to reconstruct the HV/IVC when a tumor invades all 3 HVs.

Conclusion

To the best of our knowledge, this is the first report of such HV reconstruction in combination with extracorporeal resection of huge liver cancer in updated world literature.

Safety and Efficacy of Inferior Vena Cava Reconstruction During Hepatic Resection

Background and Aims:

Patients with liver tumors involving the inferior vena cava have a poor outcome without surgery. Liver resection en bloc with inferior vena cava resection and reconstruction is now performed in many centers. The purpose of this study is to investigate the safety and efficacy of inferior vena cava reconstruction during hepatic resection.

Materials and Methods:

A review of 12 centers reporting 240 patients with combined hepatectomy and inferior vena cava resection and reconstruction for malignant tumors was performed. Sample size, patient characteristics, histological type of the tumor, method of reconstruction, complications, and long-term survival (1-, 2-, and 5-year survival) were evaluated.

Results:

A total of 240 patients from 12 institutions (male 58%) with mean age 54 years underwent combined liver resection and inferior vena cava resection and reconstruction for colorectal liver metastases (43%), cholangiocarcinomas (26%), hepatocellular carcinomas (19%), leiomyosarcomas (4%), and other tumors (7.9%). Reconstruction included primary closure (35.8%), patch repair (13.3%), or interposition graft (50.8%) In-hospital mortality was 6.25% and overall morbidity was 42.1%. 1- and 10-year survival rates were 79.7% and 28.9%, respectively.

Conclusion:

Tumors arising in or extending to inferior vena cava that require liver resection should be considered for surgery as it can be performed with an acceptable mortality and morbidity in centers with liver transplantation and hepato-pancreato-biliary facilities.

Ante situm liver resection with inferior vena cava replacement under hypothermic cardiopolmunary bypass for hepatoblastoma: Report of a case and review of the literature

INTRODUCTION

Hepatoblastoma with tumour thrombi extending into inferior-vena-cava and right atrium are often unresectable with an extremely poor prognosis. The surgical approach is technically challenging and might require major liver resection with vascular reconstruction and extracorporeal circulation. However, which is the best surgical technique is yet unclear.

PRESENTATION OF CASE

A 11-months-old boy was referred for a right hepatic lobe mass(90×78mm) suspicious of hepatoblastoma with tumoral thrombi extending into the inferior-vena-cava and the right atrium, bilateral lung lesions and serum alpha-fetoprotein level of 50.795IU/mL. After 8 months of chemotherapy (SIOPEL 2004-high-risk-Protocol), the lung lesions were no longer clearly visible and the hepatoblastoma size decreased to 61×64mm. Thus, ante situm liver resection was planned: after hepatic parenchymal transection, hypothermic cardiopulmonary bypass was started and en bloc resection of the extended-right hepatic lobe, the retro/suprahepatic cava and the tumoral trombi was performed with concomitant cold perfusion of the remnant liver. The inferior-vena-cava was replaced with an aortic graft from a blood-group compatible cadaveric donor. The post-operative course was uneventful and after 8 months of follow-up the child has normal liver function and an alpha-fetoprotein level and is free of disease recurrence with patent vascular graft.

CONCLUSIONS

We report for the first time a case of ante situ liver resection and inferior-vena-cava replacement associated with hypothermic cardiopulmonary bypass in a child with hepatoblastoma. Herein, we extensively review the literature for hepatoblastoma with thumoral thrombi and we describe the technical aspects of ante situm approach, which is a realistic option in otherwise unresectable hepatoblastoma.

Inferior Vena Cava Repair Using Serosal Patch of Small Bowel: An Experimental Study

OBJECTIVE

To evaluate the feasibility and results of using serosal patch of small bowel for repair and replacement of inferior vena cava (IVC) after resection of a part of infra-renal IVC in an animal model, as it may be encountered in extensive tumors of retroperitoneal and trauma patients.

METHODS

Five healthy sheep of both sexes were prepared. After general anesthesia and laparotomy, a defect with 1 cm width and 4cm length was made on anterior aspect of infra-renal IVC, and then an adjacent loop of small bowel was brought and sutured continuously to cover the defect of IVC as a patch graft. The observation period was two months.

RESULTS

Three of five IVCs were macroscopically patent without stenosis and thrombosis. Pathologic assay revealed complete endothelialization of serosal surface of the patch of small bowel loop. One of IVCs was completely occluded in gross evaluation and fibrous formation in pathologist review. The sheep had no sign of venous hypertension and edema of limbs. One sheep died at the night of first operation due to internal bleeding.

CONCLUSION

Serosal patch of small bowel is an accessible and feasible alternative in repair and reconstruction of IVC especially when there is restriction for use of prosthetic material in a contaminated space of abdomen.

Sonography and Transthoracic Echocardiography for Diagnosis of Systemic Cardiovascular Metastatic Tumor Thrombi

Sonography and transthoracic echocardiography (TTE) are seldom used for assessment of metastatic tumor thrombi in the cardiovascular system in routine clinical practice. We performed this retrospective study to evaluate the combination of sonography with TTE for diagnosis of metastatic tumor thrombi in heart and systemic vessels. Vascular, abdominal, pelvic, and small-part sonography was applied in 18 patients, and TTE was conducted simultaneously in 14 patients. Tumor thrombi invaded into the inferior vena cava system in 12 patients, superior vena cava system in 5 patients, and aorta in 1 patient; they extended to the right cardiac chambers in 11 patients. Six patients had diagnoses by pathologic examination. The primary neoplasms were identified by conventional imaging in 17 patients. The morphologic and echogenic characteristics of the tumor thrombi were diverse and depended on their original tumors. The thrombi were either contiguous or discrete from the original tumors. The neoplastic vascularity of the thrombi and the invasive extension were the primary characteristics that distinguished them from bland thrombi. Simultaneous application of sonography and TTE is a feasible way to comprehensively evaluate cardiovascular metastatic tumor thrombi in most patients.

Management of extensive retrohepatic vena cava defect in recipients of living donor liver transplantation

Certain complexities, such as extensive vena caval injury, unexpected dense adhesions between liver and retrohepatic vena cava, and liver tumor abutting retrohepatic vena cava, sometimes warrant resection of vena cava during living-donor liver transplantation. Because the donor graft is devoid of vena cava, reconstruction of the retrohepatic cava is required, which can be done with the use of either a cryopreserved venous graft or an artificial conduit. With only a few published reports, the experience in vena cava reconstruction with the use of expanded polytetrafluoroethylene (ePTFE) during living-donor liver transplantation remains limited. We present our experience of 4 patients who successfully underwent vena caval resection during liver transplantation for various indications, which was subsequently reconstructed with the use of ePTFE grafts. All of these patients except 1 recovered well without any undue complications, such as thrombosis or outflow inadequacies, thus proving this extensive surgical treatment to be a successful and life-saving procedure, though meticulous skills are prerequisite.

The use of biological grafts for reconstruction of the inferior vena cava is a safe and valid alternative: results in 32 patients in a single institution

BACKGROUND

Resection and reconstruction of the inferior vena cava (IVC) is occasionally required in the surgical treatment of intra-abdominal tumours. IVC reconstruction can be performed with biological or synthetic graft material, with most centres preferring synthetic grafts. In spite of the potential advantages of biological grafts in terms of handling characteristics, and safety, very limited data are available about their use in patients requiring an IVC resection.

METHODS

Medical records of 32 patients who underwent an IVC resection and reconstruction from 1990 and 2011 with autogenous peritoneo-fascial (N = 22) and bovine pericardial (N = 10) grafts were reviewed.

RESULTS

A tangential resection with patch repair was performed in 10 patients, whereas in the remaining 22 it was necessary to resect and replace a segment or all of the retrohepatic IVC. A concomitant liver resection was performed in 14 patients, nephrectomy in 10 and pancreaticoduodenectomy in 2 patients. There were no acute or late complications related to graft thrombosis or infection. Three patients died as a consequence of multi-organ failure. Overall survival at 1 and 5 years was 78% and 48%, respectively.

CONCLUSIONS

The preferential use of synthetic grafts in IVC replacement is not evidence based. Selection of an appropriate prosthetic graft for IVC reconstruction should be based on the safety and its handling features. The use of biological grafts for IVC repair is a valid alternative to current synthetic materials and may in fact be superior in terms of biocompatability, ease of handling, reduced rate of infection and improved long-term patency without permanent anticoagulation.

Resection of the liver and inferior vena cava for hepatic malignancy

BACKGROUND

Involvement of the IVC has traditionally been considered a relative contraindication to resection for advanced tumors of the liver. Combined resection of the liver and IVC for malignancy can be performed safely and results in long-term survival in select patients.

STUDY DESIGN

Sixty patients undergoing hepatic and IVC resection by the primary author from 1996 to 2012 were reviewed. Median age was 52 years. Resections were carried out for cholangiocarcinoma (n = 26), hepatocellular carcinoma (n = 16), colorectal metastases (n = 13), gastrointestinal stromal tumor (n = 2), hepatoblastoma (n = 2), and squamous cell carcinoma (n = 1). Resections performed included 27 right and 5 left trisegmentectomies and 25 right and 3 left lobectomies, including the caudate lobe. Ex vivo procedures were performed in 6 patients using veno-venous bypass and the other 54 procedures were performed using varying degrees of vascular isolation. In situ cold perfusion of the liver was used in 8 patients. The IVC was reconstructed using a tube graft (n = 38) primarily (n = 8) or with patches (n = 14).

RESULTS

There were 5 perioperative deaths (8%). Three patients died of liver failure, 1 patient died of pulmonary hemorrhage, and 1 patient died of massive pulmonary embolism. Nine patients had evidence of postoperative liver failure that resolved with supportive management. Three patients required temporary dialysis. With a median follow-up of 31 months, 14 patients have died of recurrent malignancy between 22 and 44 months, and an additional 4 patients are alive with disease at 16 to 33 months. Actuarial 1- and 5-year survival rates were 89% and 35%, respectively.

CONCLUSIONS

Inferior vena cava involvement by malignancy does not obviate liver resection. The procedure's increased risk is balanced by the possible benefits, given the lack of alternative curative approaches.