Interventional radiology in pediatric oncology

Tumor ablation in children

Tumor ablation represents an increasingly important topic in pediatric interventional radiology. Many ablative techniques are well known and established in the adult population, and the adoption of these techniques in the pediatric field is increasing. Image-guided tumor ablation represents a wide category of interventional radiology procedures that can be applied to both benign and malignant pediatric solid tumors. Tumor ablation, either alone or in combination with locoregional therapy, can have curative, debulking, or palliative effects on a wide variety of histological tumor types.

Pediatric Transplant Interventions

The field of pediatric organ transplantation has grown significantly in recent decades, with interventional radiology (IR) playing an essential role in managing pre and post-transplant complications. Pediatric transplant patients face unique challenges compared to adults, including donor-recipient size mismatch, and complications of a growing child with changing physiology. Interventional radiologists play a major role in pediatric renal and liver transplant. IR interventions begin early in the child's pretransplant journey, with diagnostic procedures such as biopsies, angiograms, and cholangiograms. These procedures are essential for understanding the etiology of organ failure and identifying potential transplant candidates. Minimally invasive therapeutic procedures may serve as bridges to transplant and may include vascular access optimization for hemodialysis, transjugular intrahepatic portosystemic shunts (TIPS) creation, and tumor embolization or ablation. After transplant, image-guided biopsies for the surveillance of graft rejection and treatment of vascular or luminal stenoses, pseudoaneurysms, and anastomotic leaks can maintain the function and longevity of the transplant organ. Careful consideration must be given to patient size and evolving anatomy, radiation exposure, and the need for deeper sedation for pediatric patients. Despite these challenges, the integration of IR in pediatric transplant care has proven beneficial, offering minimally invasive alternatives to surgery, faster recovery times, and improved outcomes.

Precision Imaging Guidance in the Era of Precision Oncology: An Update of Imaging Tools for Interventional Procedures

Interventional oncology (IO) procedures have become extremely popular in interventional radiology (IR) and play an essential role in the diagnosis, treatment, and supportive care of oncologic patients through new and safe procedures. IR procedures can be divided into two main groups: vascular and non-vascular. Vascular approaches are mainly based on embolization and concomitant injection of chemotherapeutics directly into the tumor-feeding vessels. Percutaneous approaches are a type of non-vascular procedures and include percutaneous image-guided biopsies and different ablation techniques with radiofrequency, microwaves, cryoablation, and focused ultrasound. The use of these techniques requires precise imaging pretreatment planning and guidance that can be provided through different imaging techniques: ultrasound, computed tomography, cone-beam computed tomography, and magnetic resonance. These imaging modalities can be used alone or in combination, thanks to fusion imaging, to further improve the confidence of the operators and the efficacy and safety of the procedures. This article aims is to provide an overview of the available IO procedures based on clinical imaging guidance to develop a targeted and optimal approach to cancer patients.

Factors influencing the diagnostic yield and accuracy of image-guided percutaneous needle biopsy of pediatric tumors: single-center audit of a 26-year experience

BACKGROUND

Image-guided percutaneous core needle biopsy is a common procedure for diagnosis of both solid tumors and hematological malignancies in children. Despite recent improvements, a certain rate of non-diagnostic biopsies persists.

OBJECTIVE

To assess the factors influencing the diagnostic yield and accuracy of percutaneous core needle biopsies of pediatric tumors.

MATERIALS AND METHODS

We conducted a single-center retrospective study of a 26-year experience with image-guided biopsies in children and young adults. Using uni- and multivariate analysis, we evaluated the association of diagnostic yield and accuracy with technical factors (image-guided procedure, pathological technique) and clinical factors (complication rate, histological type and anatomical location).

RESULTS

We retrieved data relating to 396 biopsies were performed in 363 children and young adults (mean age: 7.4 years). Overall, percutaneous core needle biopsy showed a diagnostic yield of 89.4% (95% confidence interval [CI] 85.9-92.2) and an accuracy of 90.9% (CI 87.6-93.6) with a complication rate of 2.5% (CI 1.2-4.6).The diagnostic yield increased with the use of advanced tissue assessment techniques (95.7% with immunohistochemistry versus 82.3% without immunohistochemistry; P < 0.0001) and an increased number of passes (mean: 3.96 for diagnostic biopsies versus 3.62 for non-diagnostic biopsies; P = 0.044).

CONCLUSION

The use of advanced pathological techniques and an increased number of passes are the two main factors influencing the diagnostic success of biopsies in pediatric tumors.

[Contribution of radio-guided biopsy in the histopathological diagnosis of childhood tumors of: experience of Rabat Child Hospital]

La biopsie radioguidée constitue une alternative à la biopsie chirurgicale invasive et à la cytologie pour le diagnostic des tumeurs pédiatriques. L'intérêt de notre étude est d’évaluer la valeur diagnostique des biopsies radioguidées examinées au laboratoire d'anatomopathologie de l'hôpital d'Enfants de Rabat (HER). L’étude a porté sur 78 biopsies radioguidées recueillies dans notre laboratoire entre janvier 2008 et décembre 2011. l’âge moyen des patients était de 5 ans et 10 mois avec une prédominance masculine (65,4%). La tumeur était abdominale dans 80% des cas, thoracique dans 15% cas, thoracique et abdominale dans 2,5% et sacrée dans 1,2%. Les biopsies étaient écho-guidées dans 90% des cas et scannoguidées dans 10% des cas. Le diagnostic histopathologique était posé dans 89% des cas. L'immuno-histochimie a été indiquée dans 35% des cas. Les diagnostics les plus fréquents étaient: tumeurs neuroblastiques (42 cas), lymphomes non hodgkiniens (10 cas), rhabdomyosarcomes (6 cas), autres (sarcome d'Ewing, néphroblastomes, tumeur myofibroblastique inflammatoire, maladies de Hodgkin, leucémie aiguë, hépatoblastome et ostéosarcome). Dans notre série, la biopsie radioguidée a permis un diagnostic histopathologique certain dans 89% des cas. Elle nécessite une étroite collaboration entre clinicien, radiologue et anatomopathologiste pour discuter son indication, afin de diminuer le nombre de biopsies peu ou non représentatives.

Ultrasound-guided core biopsy as the primary tool for tissue diagnosis in pediatric oncology

INTRODUCTION

Traditionally in pediatric oncology, biopsies were incisional, with a recent alternative of percutaneous imaging-guided biopsies. In our department, ultrasound (US)-guided core biopsy is the first choice for tissue diagnosis in the pediatric population. We retrospectively reviewed our experience and assessed the accuracy rate, safety, and availability of the procedure.

MATERIALS AND METHODS

Pediatric US-guided biopsies performed in our hospital between November 2003 and November 2011 were studied. Data collection included demographics, clinical and procedural data, and follow-up.

RESULTS

A total of 213 biopsies were performed on 191 patients: 40 known oncologic patients and 173 to establish diagnosis. Seventeen biopsies were excluded, as malignancy was not suspected. Sixty-five percent of the patients had a biopsy within a day. A total of 138 biopsies with tumor at the biopsy site were correctly diagnosed and 4 were missed. Fifty-eight patients were negative for tumor. The sensitivity of our ultrasound-guided core biopsy is 97.1%, specificity 100%, and accuracy 97.9%.We found no complication related to sedation, and 2 procedural complications-bleeding from the biopsy site and seeding of tumor cells-were reported.

DISCUSSION

We find US-guided core biopsy for suspected malignancy in the pediatric population to be highly available, safe, and very accurate, having a potential to become the procedure of choice.

Vascular pediatric interventional radiology

Interventional radiology procedures are increasingly in demand in both the adult and pediatric populations. Pediatric procedures mirror many of the adult procedures but with increased complexity due to many considerations, notably patient size. This article reviews the various vascular pediatric interventional procedures. The aim is to provide a greater exposure to the possible treatment options for pediatric patients and to facilitate understanding of the success and complications rates related to various interventions.

Paediatric interventional oncology

As is often the case with developments in interventional radiology (IR), widespread adoption of the newer techniques of interventional oncology has taken longer in paediatric than in adult practice. The three main applications of IR techniques in children with cancer are biopsy, regional therapy and supportive care (including the treatment of complications), and these are considered separately.

Recurrent, refractory, metastatic and/or unresectable pediatric sarcomas: treatment options for young people ‘off the roadmap’

Although sarcoma surgery is very important for cancer control, it is not always possible or practical to offer in some situations, including sarcoma recurrences, metastatic disease and/or unacceptable loss of function. We review some pragmatic approaches and examples of how to balance indications, risks and alternatives to control cancer in young people with sarcomas that are no longer using ‘front-line’ therapy. Radiotherapy combined with chemotherapy and outpatient ‘continuation’ chemotherapy regimens using drugs that cause less alopecia can improve function and quality of life. Some effective strategies to help cope when cure is not possible may include tumor ablation techniques performed in interventional radiology and percutaneous nerve blocks. Family centered care and effective problem solving of difficult issues can be greatly facilitated by consultation with a multidisciplinary team experienced in the management of very difficult cases. Treatment of young people with recurrent, relapsed and/or metastatic sarcoma still remains an art very much in the realm of compassion not protocol and persistent advocacy is required for the young person for whom cure may not be possible. A reduction of suffering and assistance in writing more chapters of a rich life narrative is the goal.

Issues in Imaging-Guided Tumor Ablation in Children Versus Adults

OBJECTIVE

Despite the growing use of percutaneous imaging-guided tumor ablation in adults, few reports describe its use in children except for osteoid osteoma. Our objective is to describe how tumor ablation in children and adults may differ, both to facilitate dialogue on pediatric tumor ablation and to increase awareness and use of this valuable technique.

CONCLUSION

There are numerous indications for which various ablative techniques may be safe and effective for treatment of pediatric tumors. Nonetheless, important differences between the pediatric and adult populations warrant consideration.

Interventional radiology and the care of the pediatric oncology patient

Interventional radiology has become increasingly involved in the diagnosis and management of the pediatric oncology patient. Percutaneous biopsy and needle aspiration can be performed for solid and liquid lesions with image guidance, both for the primary diagnosis and for management of sequelae of cancer therapy. Therapeutic options also can be performed with image guidance, including radiofrequency ablation and transarterial chemoembolization. When surgical resection is required, image guided tumor localization can be used to aid in identifying small lesions.

CT-guided radiofrequency ablation of pediatric Wilms tumor in a solitary kidney

Although recent results of percutaneous imaging-guided radiofrequency ablation (RFA) of various tumors in adults are promising, RFA of tumors in children has been performed in only a small number of cases. We describe the treatment of Wilms tumor in a solitary kidney in a 5-year-old girl using percutaneous CT-guided RFA. The procedure provided short-term palliation in this child for whom partial or total nephrectomy carried high risk and low likelihood of success. Although it might only be useful ultimately as a temporizing measure, oncologists and surgeons might wish to consider RFA in children who would otherwise require dialysis and renal transplantation or who are poor surgical candidates. Various specific technical issues differentiate pediatric from adult tumor ablation, including the amount of intra-abdominal fat, need for smaller grounding pads, and potential systemic effects of tissue heating.

MR-guided biopsies of lesions in the retroperitoneal space: technique and results

The purpose of this study was to evaluate the safety and precision of MRI-guided biopsies of retroperitoneal space-occupying tumors in an open low-field system. In 30 patients with indistinct retroperitoneal tumors [paraaortic lesion (n=20), kidney (n=2), suprarenal gland (n=3) and pancreas (n=5)] MR-guided biopsies were performed using a low-field system (0.2 T, Magnetom Concerto, Siemens, Germany). For the monitoring of the biopsies T1-weighted FLASH sequences (TR/TE=160/5 ms; 90 degrees ) were used in all patients and modified FLASH sequences (TR/TE=160/13 ms; 90 degrees ) in ten patients. After positioning of the needle in the tumors 114 biopsy specimens were acquired in coaxial technique with 16-gauge cutting needles (Somatex, Germany). The biopsies were successfully performed in all patients without vascular or organ injuries. The visualization of the aortic blood flow with MRI facilitated the biopsy procedures of paraaortic lesions. The size of the lesions ranged from 1.6 to 7.5 cm. The median distance of the biopsy access path was 10.4 cm. Adequate specimens were obtained in 28 cases (93.3%) resulting in a correct histological classification of 27 lesions (90%). In conclusion, MR-guided biopsies of retroperitoneal lesions using an open low-field system can be performed safely and accurately and is an alternative to CT-guided biopsies.