Positron emission tomography in patients with Hodgkin's disease: correlation to histopathologic subtypes

Presentation and diagnosis of autoimmune lymphoproliferative syndrome (ALPS)

INTRODUCTION

Autoimmune lymphoproliferative syndrome (ALPS) is a rare disorder of immune dysregulation characterized by derangements in first apoptosis signal-mediated apoptosis and elevations in CD3⁺TCRαβ⁺CD4^-CD8^- 'double negative' T cells. As our understanding of this pleomorphic disorder expands, the importance of molecular diagnosis is ever more apparent due to the growing number of disorders that may present with overlapping initial symptoms, but for which there is an ever-increasing list of therapeutic options.

AREAS COVERED

This review will cover the current understanding of the molecular biology and pathophysiology of ALPS as well as describe some of the overlapping syndromes in order to better demonstrate the importance of establishing the correct diagnosis.

EXPERT OPINION

Going forward, international, multicenter collaboration to fully characterize ALPS and the ALPS-like disorders, including with particular focus on defining the defects for those patients with undefined ALPS, is important to both continue to improve our understanding of this disorder and to drive patient care forward to provide the best outcomes. Additionally, it is probably time to re-convene an international expert panel to re-define diagnostic criteria taking into consideration the most recent available data in order to optimize patient care.

Comparison of 18F-labelled fluoro-2-deoxyglucose-PET with conventional computed tomography for staging and response assessment in paediatric and adult patients with nodular lymphocyte-predominant Hodgkin's lymphoma

BACKGROUND

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is an uncommon subtype of Hodgkin lymphoma. Data are limited regarding 18F-labelled fluoro-2-deoxyglucose (FDG)-PET use in NLPHL. We are reporting our experience with FDG-PET utility in staging and response assessment NLPHL patients.

METHODS

We retrospectively studied a population of all newly diagnosed or relapsed/refractory patients who underwent both pre-treatment contrast-enhanced computed tomography (CeCT) and an FDG-PET and also at the end of planned treatment.

RESULTS

We identified 68 patients found to have in total 312 scans, 78 paired pre-therapeutic and post-treatment CeCT and FDG-PET scans. Among them, 55 were male, with a median follow-up was 48 months. Median SUV-max was 8.3 (2.0-21.0). FDG-PET and CeCT were concordant in 80% (62/78) of staging scans. In 20% (16/78) of patients in whom a discordance was observed, FDG-PET resulted in upstaging in 13 scans and downstaging in 3 scans. The sensitivity of CeCT was 92% for nodal staging and 42% for extralymphatic staging when compared to FDG-PET. The specificity of CeCT was 98% as compared to FDG-PET. For response assessment, there was poor agreement between the CeCT and FDG-PET in assigning complete remission of disease scores as FDG-PET was able to identify the absence of disease despite the presence of a radiologically evident residual mass on CeCT. The sensitivity for CeCT compared to FDG-PET was 100% while the specificity was 43% for detection of post-treatment response.

CONCLUSION

For NLPHL, pre-therapeutic FDG-PET scan is better than CeCT staging. FDG-PET has much better specificity for response assessment than CeCT.

18F-FDG PET Imaging Features of Patients With Autoimmune Lymphoproliferative Syndrome

INTRODUCTION

Autoimmune lymphoproliferative syndrome (ALPS) is a rare immune dysregulatory condition, usually presenting in childhood with massive lymphadenopathy, splenomegaly, and an increased incidence of lymphoma. Methods to differentiate between benign ALPS adenopathy and lymphoma are needed. To this end, we evaluated the usefulness of FDG PET.

METHODS

We prospectively evaluated 76 ALPS/ALPS-like patients including FS-7-associated surface antigen (FAS) germline mutation with (n = 4) and without lymphoma (n = 50), FAS-somatic (n = 6), ALPS-unknown (n = 6), and others (n = 10) who underwent FDG PET. Uptakes in 14 nodal sites, liver, and spleen were determined.

RESULTS

In 76 ALPS patients, FDG PET showed uptake in multiple nodal sites in all but 1 patient. The highest SUVmax values in FAS mutation without lymphoma, FAS mutation with lymphoma, FAS somatic, ALPS-unknown, and other genetic mutations were a median (range) 9.2 (4.3-25), 16.2 (10.7-37.2), 7.6 (4.6-18.1), 11.5 (4.8-17.2), and 5.5 (0-15.3), respectively. Differences between uptake in the FAS group with and without lymphoma were statistically significant, but overlapped, making discrimination between individuals with/without lymphoma impossible. The spleen:liver uptake ratio was greater than 1 in 82% of patients.

CONCLUSIONS

While statistically significant differences were observed in FAS mutation ALPS with and without lymphoma, the significant overlap in FDG uptake and visual appearance in many patients prevents discrimination between patients with and without lymphoma. Similar patterns of FDG biodistribution were noted between the various ALPS subgroups.

Performance of FDG PET/CT at initial diagnosis in a rare lymphoma: nodular lymphocyte-predominant Hodgkin lymphoma

PURPOSE

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare Hodgkin lymphoma distinguished from classical Hodgkin lymphoma (cHL) by the nature of the neoplastic cells which express B-cell markers. We wanted to determine the diagnostic performance of FDG PET/CT in initial assessment and its therapeutic impact on staging.

METHODS

We retrospectively studied a population of 35 patients with NLPHL (8 previously treated for NLHPL, 27 untreated). All patients underwent an initial staging by pretherapeutic FDG PET/CT. The impact on initial stage or relapse stage was assessed by an independent physician.

RESULTS

In a per-patient analysis, the sensitivity of the pretherapeutic FDG PET/CT was 100%. In a per-site analysis, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of pretherapeutic FDG PET/CT were 100%, 99%, 97%, 100% and 99%, respectively. Pretherapeutic FDG PET/CT led to a change in the initial stage/relapse stage in 12 of the 35 patients (34%). In contrast to previous results established without FDG PET/CT, 20% of patient had osteomedullary lesions.

CONCLUSION

Pretherapeutic FDG PET/CT has excellent performance for initial staging or relapse staging of NLPHL.

Value of 18F-FDG PET versus iliac biopsy in the initial evaluation of bone marrow infiltration in the case of Hodgkin's disease: a meta-analysis

OBJECTIVE

We carried out a meta-analysis to evaluate the performance of 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) PET and PET/CT against bone marrow biopsy (BMB) in the initial diagnosis of bone marrow infiltration (BMI) in patients with Hodgkin's disease (HD).

MATERIALS AND METHODS

Retrospective and prospective studies with direct comparison of (18)F-FDG PET with BMB in the initial evaluation of BMI in HD were included. Seven eligible studies were included in the meta-analysis comprising a total of 687 patients.

RESULTS

Both (18)F-FDG PET and BMB had excellent specificity in detecting BMI. However, (18)F-FDG PET had excellent pooled sensitivity (94.5%; 95% confidence interval: 89.0-97.8%) in detecting BMI in the initial staging of HD patients, whereas the pooled sensitivity of iliac BMB was very poor (39.4%; 95% confidence interval: 30.8-48.4%). The diagnostic odds ratio, a measure of the overall diagnostic power of the test, was much higher for PET (pooled value of 1591) than for iliac BMB (pooled value of 137).

CONCLUSION

(18)F-FDG PET significantly outperforms iliac BMB in the detection of BMI in the initial staging of HD patients and therefore should be used as a first-line study. Iliac BMB has low sensitivity and a high rate of false-negative findings. Thus, a negative BMB finding cannot rule out marrow involvement in HD patients on initial staging.

Biopsy versus FDG PET/CT in the initial evaluation of bone marrow involvement in pediatric lymphoma patients

PURPOSE

The objective is to assess the role of (18)F-2-fluoro-2-deoxy-D: -glucose (FDG) positron emission tomography (PET)/CT versus bone marrow biopsy (BMB) in the initial evaluation of bone marrow (BM) involvement in pediatric lymphoma patients.

METHODS

Fifty-four pediatric patients with pathologically proven lymphoma [31 Hodgkin's disease (HD), 23 non-Hodgkin's lymphoma (NHL)] were included in this study. All patients had soft tissue biopsy and BMB and had FDG PET/CT scans within 2 weeks of biopsy.

RESULTS

Among the 31 HD patients, FDG PET/CT revealed positive BM involvement in 4 patients, while BMB revealed BM involvement in 2 patients who were also positive on FDG PET/CT imaging. Among the 23 NHL patients, FDG PET/CT revealed positive BM involvement in 8 patients, while biopsy revealed BM involvement in 5 patients on initial studies (4 of them were also positive on FDG PET/CT, and 1 was BMB positive but was negative on FDG PET/CT), plus 1 false-negative BMB study initially but positive on repeat biopsy after FDG PET/CT. The overall sensitivity of detecting BM involvement by lymphoma was 92 and 54% (p < 0.05) for FDG PET/CT and BMB, respectively. It is noted that there were more positive BMB findings in patients with abnormal FDG activities seen in the biopsy sites on PET/CT.

CONCLUSION

Our study demonstrates that FDG PET/CT has high sensitivity and accuracy and a substantial complementary value to BMB in the initial diagnosis of pediatric lymphoma, and should be employed as a first-line study.

The impact of fluorodeoxyglucose-positron emission tomography in primary staging and patient management in lymphoma patients

Fully diagnostic positron emission tomography (PET)/CT scans acquired during oral and intravenous contrast can be provided to patients and referring physicians in a single imaging session. Although FDG uptake varies, most low-grade lymphomas exhibit sufficient FDG avidity to also be staged reliably with FDG PET/CT. PET/CT imaging is more accurate for lymphoma staging than PET or CT alone and has substantial impact on patient management. This accurate whole-body glucose metabolic survey should serve as the baseline for subsequent treatment response evaluations. PET/CT has evolved to become the modality of choice for staging of nodal and extranodal lymphoma, for assessing therapeutic response, and for establishing patient prognosis.

Advanced imaging for veterinary cancer patients

This article presents an update on the recent advances made in veterinary advanced imaging specifically with regard to cross-sectional modalities (CT and MRI) and nuclear medicine (positron emission tomography [PET] and PET/CT). A brief summary of technical improvements and a review of recent literature are included to provide an overview of the progress made in this important element of the practicing veterinary oncologist's repertoire. An in-depth summary of PET is also included to introduce the technical aspects and potential clinical and research applications of this novel imaging modality in veterinary medicine.

Fluorodeoxyglucose positron emission tomography (FDG-PET) for monitoring lymphadenopathy in the autoimmune lymphoproliferative syndrome (ALPS)

Autoimmune lymphoproliferative syndrome (ALPS) is associated with mutations that impair the activity of lymphocyte apoptosis proteins, leading to chronic lymphadenopathy, hepatosplenomegaly, autoimmunity, and an increased risk of lymphoma. We investigated the utility of fluorodeoxyglucose positron emission tomography (FDG-PET) in discriminating benign from malignant lymphadenopathy in ALPS. We report that FDG avidity of benign lymph nodes in ALPS can be high and, hence, by itself does not imply presence of lymphoma; but FDG-PET can help guide the decision for selecting which of many enlarged nodes in ALPS patients to biopsy when lymphoma is suspected.

Different histopathological subtypes of Hodgkin lymphoma show significantly different levels of FDG uptake

Positron emission tomography using 2-[18F]fluoro-2-deoxy-D-glucose (FDG-PET) enables quantitative analysis of metabolic activity. This study investigated standardized uptake value (SUV) levels in the different histopathological subtypes of Hodgkin lymphoma (HL). Sixty patients with newly diagnosed HL underwent staging FDG-PET/CT after lymph node biopsy. Maximum SUV in each patient (SUV(max/total)) and in each affected region or organ (SUV(max)) were recorded. Mean SUV(max/total) was 9.3 g/ml in seven nodular lymphocyte predominance (NLP) patients, 16.3 g/ml in 38 nodular sclerosis (NS) patients, 20.8 g/ml in 11 mixed cellularity (MC) patients, and 19.5 g/ml in four patients with unclassified classical HL (CHL-NOS), (ANOVA, p = 0.011). Out of 780 sites (600 lymph node regions plus 180 organs), 208 sites were found to be affected with HL. Mean SUV(max) was 8.3 g/ml in the 12 sites with NLP, 11.2 g/ml in the 147 sites affected with NS, 14.6 g/ml in the 36 sites with MC, and 13.1 g/ml in the 13 sites with CHL-NOS (ANOVA, p = 0.002). There is a significant difference in FDG/glucose uptake between the different histopathological subtypes of HL.