[18-FDG-PET-findings in children and adolescents with Hodgkin's disease: retrospective evaluation of the correlation to other imaging procedures in initial staging and to the predictive value of follow up examinations]

A systematic review of evidence for and against routine surveillance imaging after completing treatment for childhood extracranial solid tumors

BACKGROUND

Regular off-treatment imaging is often used to assess for recurrence of disease after childhood cancer treatment. It is unclear if this increases survival, or what burden surveillance places on patients, families, or health-care services. This systematic review examines the impact of routine surveillance imaging after treatment of pediatric extracranial solid tumors.

METHODS

Collaborative patient and public involvement informed the design and interpretation of this work. Thirteen electronic databases, conference proceedings, and trial registries were searched alongside reference list checking and forward citation searching from 1990 onwards. Studies were screened and data were extracted by two researchers. Risk of bias was assessed using a modified ROBINS-I tool. Relevant outcomes were overall survival, psychological distress indicators, number of imaging tests, cost-effectiveness, and qualitative data regarding experiences of surveillance programs. PROSPERO (CRD42018103764).

RESULTS

Of 17 727 records identified, 55 studies of 10 207 patients were included. All studies used observational methods. Risk of bias for all except one study was moderate, serious, or critical. Data were too few to conduct meta-analysis; however, narrative synthesis was performed. Surveillance strategies varied, and poorly reported, involving many scans and substantial radiation exposure (eg, neuroblastoma, median 133.5 mSv). For most diseases, surveillance imaging was not associated with increased overall survival, with the probable exception of Wilms tumor. No qualitative or psychological distress data were identified.

CONCLUSIONS

At present, there is insufficient evidence to evaluate the effects of routine surveillance imaging on survival in most pediatric extracranial solid tumors. More high-quality data are required, preferably through randomized controlled trials with well-conducted qualitative elements.

Value of 18F-FDG PET and PET/CT for evaluation of pediatric malignancies

Successful management of solid tumors in children requires imaging tests for accurate disease detection, characterization, and treatment monitoring. Technologic developments aim toward the creation of integrated imaging approaches that provide a comprehensive diagnosis with a single visit. These integrated diagnostic tests not only are convenient for young patients but also save direct and indirect health-care costs by streamlining procedures, minimizing hospitalizations, and minimizing lost school or work time for children and their parents. (18)F-FDG PET/CT is a highly sensitive and specific imaging modality for whole-body evaluation of pediatric malignancies. However, recent concerns about ionizing radiation exposure have led to a search for alternative imaging methods, such as whole-body MR imaging and PET/MR. As we develop new approaches for tumor staging, it is important to understand current benchmarks. This review article will synthesize the current literature on (18)F-FDG PET/CT for tumor staging in children, summarizing questions that have been solved and providing an outlook on unsolved avenues.

Leukemia and lymphoma

Leukemia and lymphoma are the most common and third most common pediatric malignancies, respectively, and share cell lineages, but the clinical and imaging manifestations of these malignancies vary substantially. Along with providing pertinent details on classification, epidemiology, and treatment, this article reviews the current roles of imaging in the management of childhood leukemia and lymphoma, with attention to diagnosis, staging, risk stratification, therapy response assessment, and surveillance for disease relapse and adverse effects of therapy. Advances in functional imaging are also discussed to provide insights into future applications of imaging in the management of pediatric patients with leukemia and lymphoma.

18F-FDG PET for posttherapy assessment of Hodgkin's disease and aggressive Non-Hodgkin's lymphoma: a systematic review

Although studies have shown that (18)F-FDG PET, when used to assess the response of malignant lymphoma after treatment, has a strong ability to predict relapse, its diagnostic accuracy in clinical practice remains unclear. The aim of this study was to systematically review the diagnostic accuracy of (18)F-FDG PET in detecting residual disease at the completion of first-line therapy of Hodgkin's disease (HD) and aggressive non-Hodgkin's lymphoma (NHL).

METHODS

We searched relevant articles from 1966 to July 2006 using MEDLINE, EMBASE, SCOPUS, Biological Abstracts, bibliographies, review articles, and textbooks without language restriction. One assessor (for non-English-language studies) or 2 assessors (for English-language studies) independently reviewed each article to abstract relevant study characteristics and results. Relevant individual patient data or subgroup data were provided by the investigators if they were unavailable from the publications. We estimated summary receiver operating characteristic curves and confidence regions for summary sensitivity and specificity.

RESULTS

Nineteen studies consisting of 474 HD and 254 aggressive NHL patients were included. These studies had heterogeneity and suboptimal methodologic quality and reporting. Reported ranges for the sensitivity and specificity of (18)F-FDG PET in predicting disease relapse were 0.50-1.00 and 0.67-1.00, respectively, for HD and 0.33-0.77 and 0.82-1.00, respectively, for NHL. These estimates were similar when conventional imaging tests showed a residual mass. For HD studies, the summary receiver operating characteristic curves were similar irrespective of whether a residual mass was detected by conventional tests. Factors explaining the variability of diagnostic estimates were not identified.

CONCLUSION

Although currently available evidence is still limited, (18)F-FDG PET seems to have good diagnostic accuracy for assessing residual HD at the completion of first-line treatment. Clinical data on this use of (18)F-FDG PET for aggressive NHL are more limited. Prospective studies with a more rigorous research design, conduct, and reporting would more reliably reveal the clinical diagnostic accuracy of this imaging modality.

F-18 FDG-PET imaging and correlation with CT in staging and follow-up of pediatric lymphomas

BACKGROUND

We hypothesized that F-18 FDG-PET could be a useful, functional imaging modality for assessing the initial staging, response to therapy and follow-up of children diagnosed with lymphoma.

OBJECTIVE

To assess the role of whole-body F-18 FDG-PET imaging in patients with lymphoma as an initial staging modality and to measure its predictive value for monitoring the response to therapy and disease recurrence compared to CT and clinical follow-up studies.

MATERIALS AND METHODS

As part of their routine clinical care, 24 patients with histologically proven lymphoma (18 Hodgkin disease and 6 non-Hodgkin lymphoma) underwent an F-18 FDG-PET and a CT scan. A total of 28 studies were performed and the entire set of scans retrospectively reviewed. Seven studies were performed for initial staging, 12 for monitoring therapy response and 9 for detecting recurrence. Initial diagnosis was confirmed by histopathology while the gold standard at follow-up was established by clinical follow-up, additional imaging modalities and/or biopsy. F-18 FDG-PET was visually compared to CT on a lesion-by-lesion basis. Fifteen anatomic regions (seven nodal and eight extranodal) were analyzed.

RESULTS

Of the 414 regions analyzed, PET and CT were concordant in 366 (positive in 16 and negative in 350). Discordance was found in 48 regions. Overall sensitivities, specificities, and positive and negative predictive values were 78%, 98%, 94% and 90% for F-18 FDG-PET and 79%, 88%, 90% and 46% for CT, respectively.

CONCLUSION

F-18 FDG-PET imaging is a useful technique for the staging and follow-up of pediatric patients with lymphoma.

Positron emission tomography imaging for lymphoma

PURPOSE OF REVIEW

To review the current role and the limitations of F-fluorodeoxygenase positron emission tomography in the management of lymphoma, with a particular focus on studies published since January 2004.

RECENT FINDINGS

F-fluorodeoxygenase positron emission tomography should be routinely performed at the initial diagnosis of patients with suffering from Hodgkin's disease because it adds useful informations to conventional staging techniques. Residual F-fluorodeoxygenase uptake is an important prognostic factor after one or a few cycles of chemotherapy, but it is clearly too early to change patient treatment on the basis of F-fluorodeoxygenase positron emission tomography results. F-fluorodeoxygenase positron emission tomography is the best noninvasive imaging technique after treatment; however, it is always indicated to correlate positron emission tomography findings with clinical data, other imaging modalities, a biopsy, or all three to reduce the risk of false positive results. There are some concerns about the positive predictive value of positron emission tomography after treatment, especially in childhood lymphoma. Clinicians should be aware of positron emission tomography findings in specific clinical conditions in this patient population. F-fluorodeoxygenase positron emission tomography combined with computed tomography offers advantages over the two used separately and read side by side. It may be particularly useful for the planning of radiation therapy or for the planning of a surgical biopsy. Several studies have shown that F-fluorodeoxygenase positron emission tomography is definitively superior to Ga scintigraphy. New radiotracers such as F-fluorothymidine may be useful for the noninvasive assessment of proliferation in vivo.

SUMMARY

F-fluorodeoxygenase positron emission tomography has become the most important nuclear medicine imaging modality in the field of lymphoma. It should be routinely used in the treatment of lymphoma patients.

Comparison of 18F-FDG-PET and standard procedures for the pretreatment staging of children and adolescents with Hodgkin's disease

PURPOSE

The aim of this study was to perform a prospective, blinded comparison of( 18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) and conventional staging methods (CSMs) for initial staging of children and adolescents with Hodgkin's disease (HD).

METHODS

Over a period of 4 years, 55 children and adolescents with HD (mean age 15.5 years, range 3.9-18.9 years) were prospectively recruited into the study. They underwent 61 FDG-PET studies using a dedicated whole-body PET scanner as a part of their initial staging work-up. PET findings were correlated with the results of CSMs, including computed tomography (CT), ultrasound, bone scanning and bone marrow examination. Discordant findings were resolved by magnetic resonance imaging or clinical follow-up (range 2-47 months).

RESULTS

PET correctly changed the staging in 15% of patients (seven upstagings, two downstagings). Only two out of 61 patients (3%) were not accurately staged by PET; in these children, PET missed small lymphoma nodules detected on lung CT. The sensitivity of PET and CSMs for pretreatment staging was 96.5% and 87.5%, respectively; specificity was 100% and 60%, and accuracy, 96.7% and 85.2%, respectively. Upon combination of FDG-PET and lung CT, the diagnostic accuracy reached 100% in our series.

CONCLUSION

Our study showed that whole-body FDG-PET is an efficient and useful method for the initial staging of children with HD. FDG-PET in combination with lung CT should be recommended as a screening method prior to other conventional imaging modalities to plan a rational staging protocol. Large multicentre prospective studies are necessary to verify this conclusion.

Prognostic factors in pediatric Hodgkin disease

The sensitivity of pediatric Hodgkin disease to radiation and chemotherapy has resulted in cure for most children and adolescents who have been diagnosed in the past three decades. Identification of prognostic factors in clinical trials has allowed for tailoring of therapeutic approaches to improve outcome in sequential trials. Tumor burden, symptoms, clinical features, pathology, response to therapy, biology, and host factors are reviewed in this context. New developments should be directed toward identification of factors associated with biologic mechanisms of disease to facilitate the development of biologically targeted therapies that will be more efficacious and less toxic.