Sentinel lymph node biopsy in pediatric soft tissue sarcoma patients: utility and concordance with imaging

Utility of Indocyanine Green for Sentinel Lymph Node Biopsy in Pediatric Sarcoma and Melanoma

BACKGROUND

Indocyanine green (ICG) is a fluorescent dye with increasing use for adult sentinel lymph node biopsy (SLNB). The utility of ICG in pediatric oncology remains understudied. We aim to describe our experience using ICG for SLNB in pediatrics versus standard blue dye.

METHODS

A retrospective review of pediatric patients with melanoma or sarcoma who underwent SLNB with technetium plus ICG or blue dye from 2014 to 2023 at a large academic children's hospital was conducted.

RESULTS

Twenty-four patients were included; 58.3% were male with median age 13 years (range 4-21 years). The majority had a melanocytic tumor (91.7%) and 8.3% had sarcoma. All patients received technetium with concomitant blue dye (62.5%) or ICG (37.5%). ICG more reliably identified radioactive SLNs, compared to blue dye (mean 100% vs 78.3 ± 8.3%, p = 0.03). There was no significant difference in median operative time (ICG 82 min [68-203] vs blue dye 93 min [78-105], p = 0.84). Seven patients had positive SLNs (29.2%), with recurrence in 2 patients (8.3%) and 1 death (4.2%). There were no adverse events.

CONCLUSION

ICG-directed SLNB in children is a safe and effective alternative to blue dye. Use of ICG did not add to operative time, and more often identified sentinel nodes versus blue dye.

TYPE OF STUDY

Original Research Article, Retrospective Comparative Study.

LEVEL OF EVIDENCE

III.

Modern Multidisciplinary Management of Soft Tissue Sarcoma of the Extremity and Trunk

Soft tissue sarcomas (STS) of the extremity and trunk are heterogeneous and rare tumors that require coordinated multidisciplinary management. Surgical resection remains the backbone of treatment for localized tumors, with the addition of radiotherapy to surgery to achieve high rates of local control. Despite this, overall survival is limited because of significant distant metastatic risk and a lack of efficacious systemic therapies. Clinical trials have produced conflicting results on the impact of systemic therapy in the neoadjuvant and adjuvant settings for patients with localized disease, leaving systemic treatment decisions largely guided by shared decision making and prognostic prediction tools such as nomograms. This article will review the foundational data as well as latest developments in surgical, radiotherapy, and systemic management supporting current practice guidelines for localized STS of the extremity and trunk.

Fluorescent-guided surgery and the use of indocyanine green sentinel lymph node mapping in the pediatric and young adult oncology population

BACKGROUND

Technetium-99 (99m Tc) lymphoscintigraphy with blue dye injection is an accepted method for sentinel lymph node (SLN) mapping, but blue dye has known adverse effects, and injection of 99m Tc may increase time under anesthesia for pediatric patients. Indocyanine green (ICG) may serve as an adjunct to assist with visibility and identification of SLNs. We hypothesized that sensitivity of ICG was similar to blue dye in SLN biopsies.

METHODS

Thirty patients (36 procedures with 96 total specimens) underwent preoperative intradermal injection of 99m Tc, followed by intradermal injection of isosulfan blue and ICG. Test characteristics of blue dye, ICG, and 99m Tc included sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

ICG had a sensitivity of 87% and PPV of 83% for detection of 99m Tc-hot lymph nodes; blue dye had a sensitivity of 44% and PPV of 97%. For detection of pathologically confirmed lymph nodes, ICG had a sensitivity of 84% and a positive predictive value (PPV) of 91%. 99m Tc had a sensitivity of 82% and a PPV of 94%. ICG had no significant difference in odds of being positive in pathology-confirmed lymph nodes compared to 99m Tc (odds ratio [OR], 0.818; 95% confidence interval [CI], 0.3-2.172; p = .823) and had higher odds than isosulfan blue (OR, 0.025, 95% CI, 0.001-0.148; p < .001).

CONCLUSION

This study established the efficacy of ICG as an adjunct to SLNB in the pediatric and young adult population. ICG was safe, more efficacious than blue dye, and may obviate the need for lymphoscintigraphy in selected patients resulting in reduced time under anesthesia.

Imaging of pediatric extremity soft tissue tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee White Paper

Pediatric soft tissue tumors of the extremity include rhabdomyosarcoma and nonrhabdomyosarcoma neoplasms. This manuscript provides consensus-based imaging recommendations for imaging evaluation at diagnosis, during treatment, and following completion of therapy for patients with a soft tissue tumor of the extremity.

Sentinel Lymph Node Biopsy for Extremity and Truncal Soft Tissue Sarcomas: A Systematic Review of the Literature

BACKGROUND

Regional lymph node metastasis (RLNM) occurs infrequently in patients with soft tissue sarcoma (STS), although certain STS subtypes have a higher propensity for RLNM. The identification of RLNM has significant implications for staging and prognosis; however, the precise impact of node-positive disease on patient survival remains a topic of controversy. Although the benefits of sentinel lymph node biopsy (SLNB) are well documented in patients with melanoma and breast cancer, whether this procedure offers a benefit in STS is controversial.

METHODS

A systematic literature search was performed and articles reviewed to determine if SLNB in patients with extremity/truncal STS impacts disease-free or overall survival.

RESULTS

Six studies were included. Rates of sentinel lymph node positivity were heterogeneous (range 4.3-50%). The impact of SLNB on patient outcomes remains unclear. The overall quality of available evidence was low, as assessed by the Grading of Recommendations, Assessment, Development, and Evaluation system.

CONCLUSIONS

The literature addressing the impact of nodal basin evaluation on the staging and management of patients with extremity/truncal STS is confounded by heterogeneous patient cohorts and clinical practices. Multicenter prospective studies are warranted to determine the true incidence of RLNM and whether SLNB could benefit patients with clinically occult RLNM at diagnosis.

Trends of lymph node sampling and metastasis in pediatric and young adult patients with clear cell, epithelioid, and synovial sarcomas

BACKGROUND

Clear cell sarcoma of soft tissue (CCS), epithelioid sarcoma, and synovial sarcoma are rare tumors historically identified as high risk for lymph node metastasis. This study investigates incident nodal metastasis and associated survival in children and young adults with these subtypes.

PROCEDURE

Using the National Cancer Database (2004-2015), we created a retrospective cohort of 1303 patients (aged ≤25 years) who underwent local control therapy for CCS, epithelioid sarcoma, and synovial sarcoma. Kaplan-Meier curves estimated overall survival (OS) by subtype. Stratifying on subtype, Cox regressions assessed OS by lymph node sampling status and nodal metastasis.

RESULTS

There were 103 (7.9%) patients with CCS, 221 (17.0%) with epithelioid sarcoma, and 979 (75.1%) with synovial sarcoma. Lymph node sampling was more frequent in patients with CCS (56.3%) and epithelioid sarcoma (52.5%) versus synovial sarcoma (20.5%, p < .001). Synovial sarcoma metastasized to lymph nodes less frequently than CCS or epithelioid sarcoma (2.1% vs. 14.6% and 14.9%, p < .001). Across all subtypes, lymph node metastasis was associated with inferior OS (HR 2.02, CI 1.38-2.95, p < .001). Lymph node sampling was associated with improved OS in CCS (HR 0.35, CI: 0.15-0.78, p = .010), inferior OS in synovial sarcoma (HR 1.60, CI: 1.13-2.25, p = .007), and no statistical association with OS in epithelioid sarcoma.

CONCLUSIONS

Lymph node metastasis is rare in children and young adults with synovial sarcoma. Lymph node sampling procedures were not consistently performed for patients with CCS or epithelioid sarcoma, but improved OS supports routine lymph node sampling in children and young adults with CCS.

Value of the Sentinel Node Procedure in Pediatric Extremity Rhabdomyosarcoma: A Systematic Review and Retrospective Cohort Study

Background

Our aim is to show whether the sentinel node procedure (SNP) is recommendable for pediatric patients with extremity rhabdomyosarcoma (RMS). Lymph node metastases are an important prognostic factor in pediatric patients with extremity RMS. Accurate nodal staging is necessary to treat the patient accordingly. An alternative to the current recommended lymph node sampling is the sentinel node procedure (SNP).

Methods

A systematic review was performed summarizing all published cases of SNP in addition to 13 cases from our hospital and 8 cases from two other hospitals that have not been published before.

Results

For all patients (n = 55), at least one SLN was identified, but the SNP technique used was not uniform. The SNP changed the nodal classification of eight patients (17.0%) and had a false-negative rate of 10.5%.

Conclusions

The SNP is recommendable for pediatric patients with extremity RMS. It can change lymph node status and can be used to sample patients in a more targeted way than nodal sampling alone. Therefore, we recommend use of the SNP in addition to clinical and radiological nodal assessment for pediatric patients with extremity RMS.

Alternative approaches to retroperitoneal lymph node dissection for paratesticular rhabdomyosarcoma

PURPOSE

The aim of this study was to evaluate outcomes based on surgical approach for retroperitoneal lymph node dissection (RPLND) in patients with paratesticular rhabdomyosarcoma (PT-RMS).

METHODS

Patients undergoing RPLND for PT-RMS over 10 years at a single institution were retrospectively reviewed. Length of stay (LOS), complications, oral morphine equivalents per kilogram (OME/Kg), lymph node yield, and time to chemotherapy were assessed. The surgical approaches compared were: open transabdominal, open extraperitoneal, laparoscopic, and retroperitoneoscopic. For cases with lymphatic mapping, indocyanine green (ICG) was injected into the spermatic cord.

RESULTS

Twenty patients were included: five open transabdominal, six open extraperitoneal, three laparoscopic, and six retroperitoneoscopic operations. LOS was shorter in the retroperitoneoscopic group than laparoscopic (p = 0.029) and both open groups (p < 0.001). Mean OME/kg used was lowest in the retroperitoneoscopic (0.13 ± 0.15) group compared to laparoscopic (0.68 ± 0.53, p = 0.043), open transabdominal (14.90 ± 8.87, p = 0.003), and extraperitoneal (10.11 ± 2.44, p < 0.001). Time to chemotherapy was shorter for retroperitoneoscopic patients (0.13 days ± 0.15) compared to open transabdominal (15.6 days±6.5, p = 0.005). There was no difference in lymph node yield between groups. Spermatic cord ICG demonstrated iliac lymph node avidity on near-infrared spectroscopy.

CONCLUSIONS

Minimally invasive RPLND appears to offer a faster recovery without compromising lymph node yield for patients with PT-RMS.

LEVEL OF EVIDENCE

III.

The clinical and radiologic features of paediatric rhabdomyosarcoma

Rhabdomyosarcoma is the most common soft-tissue sarcoma in children. The most common sites are head and neck, genitourinary tract and extremities. In this review we outline the clinical and radiologic features of paediatric rhabdomyosarcoma, as well as imaging considerations and imaging of relapse.

Functional and anatomical imaging in pediatric oncology: which is best for which tumors

Functional imaging techniques are playing an increasingly important role in the management of pediatric cancer. Technological advances have pushed the development of hybrid imaging techniques, including positron emission tomography (PET)/CT, PET/MR and single-photon emission computed tomography (SPECT)/CT. Together with an increasing need to identify surrogate biomarkers for response to novel therapies, the use of functional imaging techniques, which had been reserved primarily for lymphoma patients, is now being recognized as standard of care for the management of many other pediatric solid tumors. The purpose of this review is to summarize recent data describing the use of functional and metabolic imaging strategies for the staging and response assessment of common pediatric solid tumors, and to offer some guidance as to which techniques are most appropriate for which tumor types.

An update in the management of pediatric sarcoma

PURPOSE OF REVIEW

Nonrhabdomyosarcoma soft tissue sarcoma (NRSTS) is a rare subgroup of malignancy in childhood that is composed of a variety of soft tissue and bony tumors. Prognosis for resectable localized disease is usually good and improved with systemic treatment. However, survival from locally advanced and metastatic disease remains poor. There have been numerous preclinical and clinical studies to define histopathology, biology, and genetic alteration of sarcomas. The purpose of this review is to clarify the progress in the management of NRSTS.

RECENT FINDINGS

Genomic analysis, including the use of next-generation sequencing, has revealed fusion transcripts or specific genetic alterations which provide diagnostic biomarkers and potential targets for novel therapies.

SUMMARY

Most cases are sporadic, but some are associated with genetic predispositions. Most present as a painless mass and diagnosis is frequently delayed because of a low index of suspicion. There is a wide array of histopathological subtypes. Investigations usually involve core, incisional or excisional biopsy for tissue diagnosis, and cross-sectional and nuclear imaging for staging. Management of pediatric sarcoma is largely dependent on the patient's histopathological diagnosis, age, disease stage, and co-morbidities but usually involves a combination of systemic and local therapies. Preclinical studies and phase I/II trials of newer targeted therapies are ongoing.

Defining the incidence and clinical significance of lymph node metastasis in soft tissue sarcoma

INTRODUCTION

The incidence and clinical significance of lymph node metastasis (LNM, N1) in soft tissue sarcoma (STS) is unclear. Recent studies have focused on extremity/trunk STS (ETSTS). We sought to define the subgroup of patients with LNM at sarcoma diagnosis across all disease sites and histologies.

METHODS

We identified and categorized 89,870 STS patients from the National Cancer Data Base (1998-2012) by nodal stage. Pathologically confirmed LNM (pN1) were identified in 1404 patients; 1750 had clinically suspicious but not pathologically confirmed LNM (cN1). Survival analyses were performed by Kaplan-Meier method.

RESULTS

Of 3154 patients (3.5%) with pN1 or cN1 LNM at presentation, 1310 had synchronous distant metastasis (M1). LNM affected a small proportion of patients (5.8% head/neck, 5.3% intrathoracic, 5.1% intra-abdominal, 2.0% ETSTS). Angiosarcoma (6%), epithelioid (13%), clear cell (16%), and small cell sarcoma (19%) had the highest incidence of LNM, although liposarcoma, fibrous histiocytoma, and leiomyosarcoma accounted for the greatest number of LNM patients. For pN1M0 disease, median overall survival (OS) was 28.2 months, varying by histology. Among patients with pN1M0 STS, angiosarcoma, clear cell sarcoma, leiomyosarcoma, and fibrous histiocytoma were associated with worse median OS (19.4, 23.8, 27.1, and 29.3 months) compared to epithelioid sarcoma and liposarcoma (49.6 and 56.0 months, p < 0.001).

CONCLUSION

Despite clinical suspicion, pathologic LN evaluation in STS is inconsistently performed. LNM occurs across anatomic disease sites and is unevenly distributed across histologies. Although M1 disease portends poor prognosis regardless of LN status, LNM predicts worse OS in a histology-dependent manner in M0 disease.

Local Recurrence of Extremity Soft Tissue Sarcoma

The management of recurrent soft tissue sarcoma is a challenging problem for clinicians and has a significant physical, mental, emotional, and oncologic impact for the patient. Despite excellent limb-preservation therapies, approximately one-quarter of patients may eventually develop recurrence of disease. How to most appropriately manage these patients is a matter of debate. Several treatment options exist, including surgical resection, irradiation, systemic chemotherapy, amputation, and regional therapies. This article highlights the management of recurrent extremity soft tissue sarcoma.

Pediatric Sarcomas

Pediatric sarcomas are a heterogeneous group of tumors accounting for approximately 10% of childhood solid tumors. Treatment is focused on multimodality therapy, which has improved the prognosis over the past two decades. Current regimens focus on decreasing treatment for low-risk patients to decrease the long-term side effects while maximizing therapy for patients with metastatic disease to improve survival. Pediatric sarcomas can be divided into soft tissue sarcomas and osseous tumors. Soft tissue sarcomas are further delineated into rhabdomyosarcomas, which affect young children and nonrhabdomyosarcomas, which are most common in adolescents. The most common bone sarcomas are osteosarcomas and Ewing's sarcoma.

Detection of lymph node metastases in pediatric and adolescent/young adult sarcoma: Sentinel lymph node biopsy versus fludeoxyglucose positron emission tomography imaging-A prospective trial

BACKGROUND

Lymph node metastases are an important cause of treatment failure for pediatric and adolescent/young adult (AYA) sarcoma patients. Nodal sampling is recommended for certain sarcoma subtypes that have a predilection for lymphatic spread. Sentinel lymph node biopsy (SLNB) may improve the diagnostic yield of nodal sampling, particularly when single-photon emission computed tomography/computed tomography (SPECT-CT) is used to facilitate anatomic localization. Functional imaging with positron emission tomography/computed tomography (PET-CT) is increasingly used for sarcoma staging and is a less invasive alternative to SLNB. To assess the utility of these 2 staging methods, this study prospectively compared SLNB plus SPECT-CT with PET-CT for the identification of nodal metastases in pediatric and AYA patients.

METHODS

Twenty-eight pediatric and AYA sarcoma patients underwent SLNB with SPECT-CT. The histological findings of the excised lymph nodes were then correlated with preoperative PET-CT imaging.

RESULTS

A median of 2.4 sentinel nodes were sampled per patient. No wound infections or chronic lymphedema occurred. SLNB identified tumors in 7 of the 28 patients (25%), including 3 patients who had normal PET-CT imaging of the nodal basin. In contrast, PET-CT demonstrated hypermetabolic regional nodes in 14 patients, and this resulted in a positive predictive value of only 29%. The sensitivity and specificity of PET-CT for detecting histologically confirmed nodal metastases were only 57% and 52%, respectively.

CONCLUSIONS

SLNB can safely guide the rational selection of nodes for biopsy in pediatric and AYA sarcoma patients and can identify therapy-changing nodal disease not appreciated with PET-CT. Cancer 2017;155-160. © 2016 American Cancer Society.

Prognostic Factors for Outcome in Localized Extremity Rhabdomyosarcoma. Pooled Analysis from Four International Cooperative Groups

BACKGROUND

Extremity rhabdomyosarcomas do not always show satisfactory outcomes. We analyzed data from 643 patients treated in 14 studies conducted by European and North American groups between 1983 and 2004 to identify factors predictive of outcome.

PROCEDURE

Clinical factors, including age; histology; site of primary (hand and foot vs. other); size; invasiveness (T stage); nodal involvement (N stage); and treatment factors, including post-surgical group; chemotherapy type and duration; radiotherapy; and treatment (before or after 1995); were evaluated for impact on overall survival (OS).

RESULTS

5-year OS were 67% (se 1.8). Multivariate analysis showed that lower OS correlated with age >3 years, T2 and N1 stage, incomplete initial surgery, treatment before 1995, and European cooperative group treatment. Patients with gross residual disease after initial incomplete resection/biopsy had similar outcomes in both continental groups. The better global survival of patients treated in American studies was accounted for by differences in outcome in the subset of those with grossly resected tumors (OS 86% [se 3] for COG patients vs. 68% [se 4] for European patients (P = 0.004)). When excluding chemotherapy duration from the model, analysis in this subset of patients showed that cooperative group (P = 0.001), site (P = 0.001), and T stage (P = 0.05) were all significant. However, after adding duration of chemotherapy (≥27 weeks) to the model, only primary site remained significant (P = 0.006).

CONCLUSION

This meta-analysis confirms the role of many established prognostic factors but identifies for the first time that chemotherapy duration may have an impact on outcome in patients with grossly resected tumors.

Current management of pediatric soft tissue sarcomas

Pediatric soft tissue sarcomas are a group of malignant neoplasms arising within embryonic mesenchymal tissues during the process of differentiation into muscle, fascia and fat. The tumors have a biphasic peak for age of incidence. Rhabdomyosarcoma (RMS) is diagnosed more frequently in younger children, whereas adult-type non-RMS soft tissue sarcoma is predominately observed in adolescents. The latter group comprises a variety of rare tumors for which diagnosis can be difficult and typically requires special studies, including immunohistochemistry and molecular genetic analysis. Current management for the majority of pediatric sarcomas is based on the data from large multi-institutional trials, which has led to great improvements in outcomes over recent decades. Although surgery remains the mainstay of treatment, the curative aim cannot be achieved without adjuvant treatment. Pre-treatment staging and risk classification are of prime importance in selecting an effective treatment protocol. Tumor resectability, the response to induction chemotherapy, and radiation generally determine the risk-group, and these factors are functions of tumor site, size and biology. Surgery provides the best choice of local control of small resectable tumors in a favorable site. Radiation therapy is added when surgery leaves residual disease or there is evidence of regional spread. Chemotherapy aims to reduce the risk of relapse and improve overall survival. In addition, upfront chemotherapy reduces the aggressiveness of the required surgery and helps preserve organ function in a number of cases. Long-term survival in low-risk sarcomas is feasible, and the intensity of treatment can be reduced. In high-risk sarcoma, current research is allowing more effective disease control.