The utility of FDG PET in diagnosis and follow-up of lymphoma in childhood

Diagnosis and management of lymphoblastic lymphoma in children, adolescents and young adults

Lymphoblastic lymphoma (LBL) is the second most common type of non-Hodgkin Lymphoma (NHL) in children, adolescents, and young adults (CAYA), accounting for 25-35% of all cases. T-lymphoblastic lymphoma (T-LBL) comprises 70-80% of cases, while precursor B-lymphoblastic lymphoma (pB-LBL) makes up the remaining 20-25% of cases. Event-free and overall survival (EFS and OS) for paediatric LBL patients both exceed 80% with current therapies. Treatment regimens, especially in T-LBL with large mediastinal tumours, are complex with significant toxicity and long-term complications. Though prognosis overall is good for T-LBL and pB-LBL with upfront therapy, outcomes for patients with relapsed or refractory (r/r) disease remain dismal. Here, we review new understanding about the pathogenesis and biology of LBL, recent clinical results and future directions for therapy, and remaining obstacles to improve outcomes while reducing toxicity.

Multimodality imaging findings of infection-induced tumors

Several infections can predispose to certain malignancies in different body parts. These infections include viral, bacterial, and fungal pathogens. Imaging plays a vital role in the diagnosis, staging, and management of these neoplastic conditions. Furthermore, it can help in differentiating infection-related non-neoplastic processes that can mimic malignancies. Both radiologists and clinicians should be familiar with these conditions. This review discusses the epidemiology, pathogenesis, and imaging features of infection-related tumors.

Infection of cardiac prosthetic valves and implantable electronic devices: early diagnosis and treatment

There has been a recent rise in the use of implantable cardiac devices, mostly valves but also electronic ones, such as pacemakers, and implantable defibrillators. The increasing use of these devices had as a consequence the raised incidence of endocarditis, an infrequent but morbid complication of these procedures. Thus, early diagnosis of the implantable cardiac devices related infection and endocarditis became pivotal for appropriate management. For diagnostic purposes, the modified Duke criteria are widely used, which are based on clinical and imaging findings, in addition to serological analyses and blood cultures. 18F-fluoro-2-deoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is a recently employed method in order to improve the early diagnosis of endocarditis as well as infection of the implantable device. It is likely, that combining the modified Duke criteria with the FDG PET/CT, will increase the sensitivity and specificity of diagnosis and will guide the treating physician to an early and appropriate management.

Diagnosis and treatment of limbic encephalitis in the cancer patient

Limbic encephalitis is an inflammatory process involving the limbic structures of the brain, manifested with short-term memory deficits, confusion, depression and seizures. It is usually a paraneoplastic condition but it may also appear as a nonparaneoplastic syndrome. Patients with this condition may exhibit a variety of antibodies in their serum or/and cerebrospinal fluid targeting basement membrane components that bind to a variety of neurotransmitter receptors such as α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid and GABA B and proteins associated to the ion channels such as LGI1, Caspr2 or intracellular components. Flurodeoxyglucose PET/computed tomography usually demonstrates increased uptake in the limbic structures, and it may reveal the site of the primary tumor. Treatment consists of tumor removal if possible. Symptomatic treatment includes steroids, gamma immune globulin, plasma exchange, immunosuppressive therapies and anti-epileptic drugs. Prognosis is better when it is associated with antibodies against basement membrane rather than intracellular antibodies.

Lymphoblastic lymphoma in children and adolescents: review of current challenges and future opportunities

Lymphoblastic lymphoma (LBL) is the second most common type of Non-Hodgkin Lymphoma (NHL) in childhood and adolescence, accounting for 25-35% of all cases. The majority, 70-80%, is of T-lymphoblastic origin while 20-25% arise from B lymphoblasts. With current therapy, the event-free and overall survivals for paediatric LBL patients now exceeds 80%. Therapy, especially in T-LBL with large mediastinal tumours, is challenging, with both significant morbidity and late sequela. An additional challenge is the dismal prognosis of patients with refractory or relapsed disease. This review article will focus on the growing knowledge of the pathogenesis and biology of LBL, recent advances and challenges in the therapy of LBL, and ongoing and future efforts and opportunities in optimizing therapy and developing novel targeted treatment approaches.

Italian Multicenter Study on Accuracy of 18F-FDG PET/CT in Assessing Bone Marrow Involvement in Pediatric Hodgkin Lymphoma

INTRODUCTION

The present study investigated the utility of fluorine-18 (¹⁸F) fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) in assessing bone marrow involvement (BMI) compared with bone marrow biopsy (BMB) in newly diagnosed pediatric Hodgkin lymphoma (HL).

PATIENTS AND METHODS

A total of 224 pediatric patients with HL underwent ¹⁸F-FDG PET/CT at staging. BMB or follow-up imaging was used as the standard of reference for the evaluation of BMI.

RESULTS

¹⁸F-FDG PET/CT was negative for BMI in 193 cases. Of the 193 patients, the findings for 16 were originally reported as doubtful and later interpreted as negative for BMI, with negative findings on follow-up imaging and BMB. At BMB, 1 of the 16 patients (6.25%) had BMI. Of the 193 patients, 192 (99.48%) had negative BMB findings. Thus, the ¹⁸F-FDG PET/CT findings were truly negative for 192 patients and falsely negative for 1 patient for BMI.

CONCLUSION

¹⁸F-FDG PET/CT showed high diagnostic performance in the evaluation of BMI in pediatric HL. Thus, BMB should be ideally reserved for patients presenting with doubtful ¹⁸F-FDG PET/CT findings for BMI.

Nuclear Medicine in Pediatric and Adolescent Tumors

Nuclear medicine has an important role in the management of many cancers in pediatric age group with multiple imaging modalities and radiopharmaceuticals targeting various biological uptake mechanisms. 18-Flourodeoxyglucose is the radiotracer of choice especially in patients with sarcoma and lymphoma. (18)FDG-PET, for sarcoma and lymphomas, is proved to be superior to conventional imaging in staging and therapy response. Although studies are limited in pediatric population, (18)FDG-PET/CT has found its way through international guidelines. Limitations and strengths of PET imaging must be noticed before adapting PET imaging in clinical protocols. Established new response criteria using multiple parameters derived from (18)FDG-PET would increase the accuracy and repeatability of response evaluation. Current data suggest that I-123 metaiodobenzylguanidine (MIBG) remains the tracer of choice in the evaluation of neuroblastoma (NB) because of its high sensitivity, specificity, diagnostic accuracy, and prognostic value. It is valuable in determining the response to therapy, surveillance for disease recurrence, and in selecting patients for I-131 therapy. SPECT/CT improves the diagnostic accuracy and the interpretation confidence of MIBG scans. (18)FDG-PET/CT is an important complementary to MIBG imaging despite its lack of specificity to NB. It is valuable in cases of negative or inconclusive MIBG scans and when MIBG findings underestimate the disease status as determined from clinical and radiological findings. F-18 DOPA is promising tracer that reflects catecholamine metabolism and is both sensitive and specific. F-18 DOPA scintigraphy provides the advantages of PET/CT imaging with early and short imaging times, high spatial resolution, inherent morphologic correlation with CT, and quantitation. Regulatory and production issues currently limit the tracer's availability. PET/CT with Ga-68 DOTA appears to be useful in NB imaging and may have a unique role in selecting patients for peptide receptor radionuclide therapy with somatostatin analogues. C-11 hydroxyephedrine PET/CT is a specific PET tracer for NB, but the C-11 label that requires an on-site cyclotron production and the high physiologic uptake in the liver and kidneys limit its use. I-124 MIBG is useful for I-131 MIBG pretherapeutic dosimetry planning. Its use for diagnostic imaging as well as the use of F-18 labeled MIBG analogues is currently experimental. PET/MR imaging is emerging and is likely to become an important tool in the evaluation. It provides metabolic and superior morphological data in one imaging session, expediting the diagnosis and lowering the radiation exposure. Radioactive iodines not only detect residual tissue and metastatic disease but also are used in the treatment of differentiated thyroid cancer. However, these are not well documented in pediatric age group like adult patients. Use of radioactivity in pediatric population is very important and strictly controlled because of the possibility of secondary malignities; therefore, management of oncological cases requires detailed literature knowledge. This article aims to review the literature on the use of radionuclide imaging and therapy in pediatric population with thyroid cancer, sarcomas, lymphoma, and NB.

Clinical Significance of Pretreatment FDG PET/CT in MIBG-Avid Pediatric Neuroblastoma

PURPOSE

¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) imaging is well known to have clinical significance in the initial staging and response evaluation of the many kinds of neoplasms. However, its role in the pediatric neuroblastoma is not clearly defined. In the present study, the clinical significance of FDG-PET/computed tomography (CT) in ¹²³I- or ¹³¹I-metaiodobenzylguanidine (MIBG)-avid pediatric neuroblastoma was investigated.

METHODS

Twenty patients with neuroblastoma who undertook pretreatment FDG PET/CT at our institute between 2008 and 2015 and showed MIBG avidity were retrospectively enrolled in the present study. Clinical information-including histopathology, and serum markers-and several PET parameters-including SUVmax of the primary lesion (Psuv), target-to-background ratio (TBR), metabolic tumor volume (MTV), and coefficient of variation (CV)-were analyzed. The prognostic effect of PET parameters was evaluated in terms of progression-free survival (PFS).

RESULTS

Total 20 patients (4.5 ± 3.5 years) were divided as two groups by disease progression. Six patients (30.0 %) experienced disease progression and one patient (5.0 %) died during follow-up period. There were not statistically significant in age, stage, MYCN status, primary tumor size, serum lactate dehydrogenase (LDH), neuron-specific enolase (NSE), and ferritin level between two groups with progression or no progression. However, Psuv (p = 0.017), TBR (p = 0.09), MTV (p = 0.02), and CV (p = 0.036) showed significant differences between two groups. In univariate analysis, PFS was significantly associated with Psuv (p = 0.021) and TBR (p = 0.023).

CONCLUSIONS

FDG-PET parameters were significantly related with progression of neuroblastoma. FDG-PET/CT may have the potential as a valuable modality for evaluating prognosis in the patients with MIBG-avid pediatric neuroblastoma.

Role of FDG-PET scan in the management of pediatric mature B cell non-Hodgkin's lymphoma. CCHE experience

AIM OF WORK

To evaluate the sensitivity (Se), specificity (Sp), and predictive values (PV) of PET scan during management of pediatric mature B cell non-Hodgkin's lymphoma (NHL) in comparison with conventional computed tomography (CT) scan.

PATIENTS AND METHODS

A retrospective study enrolled on pediatric NHL patients at Children Cancer Hospital Egypt (CCHE) during the period from July 2007 to the end of June 2013.

RESULTS

For 115 pediatric patients diagnosed with mature B cell NHL, 152 PET and 152 CT scans were done simultaneously. Median age was 5.7years. They were 85 males (74%) and 30 females (26%). One hundred twenty six scans (82.9%) were done for 100 (87%) Burkitt lymphoma (BL) patients, while 26 scans (17.1%) were done for 15 (13.0%) patients with diffuse large B cell NHL (DLBC). Nineteen examination (12.5%) were done before starting chemotherapy (group 1), 107 (70.3%) at time of evaluation (group 2), and 26 (17.1%) during follow up (group C). Overall sensitivity was 91.6% for PET and 70.0% for conventional CT (p=0.02). Specificity was 84.1% for PET and 58.9% for CT (p<0.001). Positive predictive value (PPV) for PET was 50%, while was 22% for CT scan (p<0.001). Negative predictive value (NPV) for PET was 98%, and 92% for CT (p=0.01).

CONCLUSION

PET scan is significantly more sensitive than conventional CT in the management of aggressive pediatric mature B cell NHL. PET negativity is an excellent indicator of tumor response.

International Pediatric Non-Hodgkin Lymphoma Response Criteria

PURPOSE

Response criteria are well established for adult patients with non-Hodgkin lymphoma (NHL). A revised set of response criteria in adults with NHL was recently published. However, NHL in children and adolescents involves different histologies, primary sites of disease, patterns of metastatic spread, approaches to therapy, and responses to treatment compared with adult NHL. However, there are no standardized response criteria specific to pediatric NHL. Therefore, we developed international standardized methods for assessing response to therapy in children and adolescents with NHL.

METHODS

An international multidisciplinary group of pediatric oncologists, pathologists, biologists, and radiologists convened during and after the Third and Fourth International Childhood, Adolescent and Young Adult NHL Symposia to review existing response and outcome data, develop methods for response evaluation that reflect incorporation of more sensitive technologies currently in use, and incorporate primary and metastatic sites of disease for the evaluation of therapeutic response in children and adolescents with NHL.

RESULTS

Using the current adult NHL response criteria as a starting point, international pediatric NHL response criteria were developed incorporating both contemporary diagnostic imaging and pathology techniques, including novel molecular and flow cytometric technologies used for the determination of minimal residual disease.

CONCLUSION

Use of the international pediatric NHL response criteria in children and adolescents receiving therapy for NHL incorporates data obtained from new and more sensitive technologies that are now being widely used for disease evaluation, providing a standardized means for reporting treatment response.

Pediatric lymphomas and histiocytic disorders of childhood

Although there have been dramatic improvements in the treatment of children with non-hodgkin lymphoma, hodgkin lymphoma and histiocytic disorders over the past 3 decades, many still relapse or are refractory to primary therapy. In addition, late effects such as 2nd malignancies, cardiomyopathy and infertility remain a major concern. Thus, this review focuses on the current state of the science and, in particular, novel treatment strategies that are aimed at improving outcomes for all pediatric patients with lymphoma and histiocytic disorders while reducing treatment related morbidity.

PET/CT-guided treatment planning for paediatric cancer patients: a simulation study of proton and conventional photon therapy

OBJECTIVE

To investigate the impact of including fluorine-18 fludeoxyglucose ((18)F-FDG) positron emission tomography (PET) scanning in the planning of paediatric radiotherapy (RT).

METHODS

Target volumes were first delineated without and subsequently re-delineated with access to (18)F-FDG PET scan information, on duplicate CT sets. RT plans were generated for three-dimensional conformal photon RT (3DCRT) and intensity-modulated proton therapy (IMPT). The results were evaluated by comparison of target volumes, target dose coverage parameters, normal tissue complication probability (NTCP) and estimated risk of secondary cancer (SC).

RESULTS

Considerable deviations between CT- and PET/CT-guided target volumes were seen in 3 out of the 11 patients studied. However, averaging over the whole cohort, CT or PET/CT guidance introduced no significant difference in the shape or size of the target volumes, target dose coverage, irradiated volumes, estimated NTCP or SC risk, neither for IMPT nor 3DCRT.

CONCLUSION

Our results imply that the inclusion of PET/CT scans in the RT planning process could have considerable impact for individual patients. There were no general trends of increasing or decreasing irradiated volumes, suggesting that the long-term morbidity of RT in childhood would on average remain largely unaffected.

ADVANCES IN KNOWLEDGE

(18)F-FDG PET-based RT planning does not systematically change NTCP or SC risk for paediatric cancer patients compared with CT only. 3 out of 11 patients had a distinct change of target volumes when PET-guided planning was introduced. Dice and mismatch metrics are not sufficient to assess the consequences of target volume differences in the context of RT.

Prognostic Value and Clinical Impact of (18)FDG-PET in the Management of Children with Burkitt Lymphoma after Induction Chemotherapy

OBJECTIVE

Burkitt lymphoma (BL) is a rare and aggressive form of B-cell lymphoma that is curable using intensive chemotherapy. Obtaining a complete response (CR) at the end of induction chemotherapy is a major prognostic factor. This study retrospectively evaluates the potential impact of (18)FDG-PET in the management of children with BL after induction chemotherapy, and the prognostic performance of the Deauville criteria.

METHODS

Nineteen children with BL treated according to the French LMB2001 protocol between 2005 and 2012 were included. (18)FDG-PET and conventional imaging (CI) were performed after induction chemotherapy to confirm CR. (18)FDG-PET was interpreted according to Deauville criteria with follow-up and/or histology as the gold standard.

RESULTS

(18)FDG-PET was negative in 15 cases, in agreement with CI in 9/15 cases. The six discordant cases confirmed to be negative by histology, were considered as true negative for (18)FDG-PET. Negative predictive value (NPV) of CI and (18)FDG-PET were 73 and 93%, respectively. The 5-year progression-free survival (PFS) was significantly higher in patients with negative (18)FDG-PET than those with positive (18)FDG-PET (p = 0.011).

CONCLUSION

(18)FDG-PET interpreted using Deauville criteria can help confirm CR at the end of induction chemotherapy, with a prognostic impact on 5-year PFS. Its high NPV could limit the use of residual mass biopsy. Given the small size of our population, these results need to be confirmed by future prospective studies on a larger population.

Paraneoplastic immune-mediated neurological effects of systemic cancers

Cancer patients may develop paraneoplastic neurological conditions associated with autoantibodies directed against neural or neuromuscular tissues. These syndromes are frequently manifested in advance of the cancer presentation by several months or years necessitating a detailed and expensive investigation to search for the presence of a malignancy. In such cases additional assistance may be obtained by the early employment of whole body 18F flurodeoxyglucose positron emission tomography as a cancer screening imaging procedure for early cancer diagnosis and potential therapy. Effective therapy of the primary cancer consists the best current therapy for a given paraneoplastic syndrome. However, other forms of immune modulation, such as plasma exchange, intravenous gamma globulin, other immune therapies and symptomatic treatment for certain PNS may have additional benefit.

Lymphoma and tuberculosis: temporal evolution of dual pathology on sequential 18F-FDG PET/CT

Tuberculosis can often be seen in patients undergoing chemotherapy for lymphoma, especially in endemic countries. As both tuberculosis and lymphoma can lead to hypermetabolic lesions of F-FDG PET/CT, a diagnostic dilemma often ensues. We present the sequential F-FDG PET/CT images of a 22-year-old female patient with Hodgkin lymphoma who developed tuberculosis and later relapse of lymphoma. These images present the temporal evaluation of the dual pathology on F-FDG PET/CT.

Detection of a metastatic lesion and tiny yolk sac tumors in two teenage patients by FDG-PET: report of two cases

We herein report the efficacy of FDG-PET for detecting yolk sac tumors in two teenage patients. One patient had a rare bone metastasis and the other had tiny recurrent lesions at the mediastinum. Both lesions were difficult to detect by conventional diagnostic modalities. In contrast, FDG-PET was very effective for detecting these lesions. Furthermore, the SUVmax of the lesion reflected the tumor activity, which was also suggested by the fluctuating values of serum alpha-fetoprotein (AFP), an established marker of yolk sac tumors. FDG-PET may be a useful procedure to detect tiny and metastatic, pediatric yolk sac tumors.