FDG-PET/CT in lymphoma

Canine Multicentric Lymphoma: Diagnostic, Treatment, and Prognostic Insights

Lymphoma accounts for 24% of all documented canine neoplasms and 85% of hematological malignancies, while multicentric lymphoma corresponds to 84% of all canine lymphomas. Canine lymphomas of B-cell origin account for 60% to 80% of lymphomas. Similar to humans, the histologic grade, architecture, as well as immunophenotype determination, are crucial. These lesions are the most prevalent spontaneous tumors in dogs and this species may be a valuable animal model for the study of human non-Hodgkin's lymphoma. Therefore, it is important to investigate and assess therapeutic responses and to seek predictive and prognostic factors in order to allow for the development of an individualized and more effective therapy that increases survival. This review aims to describe current knowledge on the diagnosis, treatment, and prognostic factors of canine multicentric lymphoma.

Recent Advances in Nanobiotechnology for the Treatment of Non-Hodgkin's Lymphoma

Lymphoma is the eighth most common type of cancer worldwide. Currently, lymphoma is mainly classified into two main groups: Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL), with NHL accounting for 80% to 90% of the cases. NHL is primarily divided into B, T, and natural killer (NK) cell lymphoma. Nanotechnology is developing rapidly and has made significant contributions to the field of medicine. This review summarizes the advancements of nanobiotechnology in recent years and its applications in the treatment of NHL, especially in diffuse large B cell lymphoma (DLBCL), primary central nervous system lymphoma (PCNSL), and follicular lymphoma (FL). The technologies discussed include clinical imaging, targeted drug delivery, photodynamic therapy (PDT), and thermodynamic therapy (TDT) for lymphoma. This review aims to provide a better understanding of the use of nanotechnology in the treatment of non-Hodgkin's lymphoma.

Role of Positron Emission Tomography with 2-Deoxy-2-[fluorine-18]fluoro-D-glucose Integrated with Computed Tomography in the Evaluation of Hepatic Metabolic Activity due to Steatosis in Lymphoma Patients and its Impact on Deauville Score

BACKGROUND: Liver uptake of 2-Deoxy-2-[fluorine-18]fluoro-D-glucose integrated (18F-FDG) is taken as the reference tissue in interpretation of Deauville score (DS), which is considered a response assessment. AIM: This study was conducted to evaluate the prevalence of hepatic steatosis in patients with lymphoma and the impact of hepatic metabolic activity due to steatosis on 18F-FDG liver uptake and its effect on DS. MATERIAL AND METHODS: This prospective study was conducted on 77 cases. Seventy-seven patients had baseline positron emission tomography/computed tomography (PET/CT), 69 patients had interim PET/CT, 31 patients had end of treatment (EOT) PET/CT, and 3 patients had follow-up (FU) PET/CT after EOT. The study included 49 female patients (63.6%) and 28 male patients (36.4%). The mean age = 39.5 + 13. Forty-one patients (53.2%) diagnosed as non-Hodgkin lymphoma [HL] while 36 patients (46.8%) diagnosed as HL. Steatosis was diagnosed on the unenhanced CT part of PET/CT examinations using a cutoff value of 42 Hounsfield units. Both maximum standardized uptake value (SUVmax) and SULmax were recorded on the liver and the tumor target lesion. DS was then computed. RESULTS: Among 77 cases, prevalence of steatosis in baseline (10/77, 12.9%), interim (13/69, 18.8%), and EOT/FU (4/31, 12.9%), there was no significant difference in hepatic steatosis during their time course of their treatment. There was correlation between Liver SUVmax with body mass index (BMI) in each of interim and EOT PET/CT. Regarding SULmax, there was no correlation with BMI. There was no change in interpretation of DS using either SUVmax or SULmax. CONCLUSION: Steatosis has no practical issue regarding liver metabolic activity (either SUVmax or SULmax) in interpretation of DS. Liver SUVmax is affected by body weight. Unlike, SULmax is not affected by body weight.

Role of interim and end of treatment positron emission tomography for response assessment and prediction of relapse in posttransplant lymphoproliferative disorder

Background: Fluorine-18-fluorodeoxyglucose positron emission tomography (PET) has an established and central role in diagnosis, staging and response evaluation of lymphoproliferative diseases. It has shown a high sensitivity and specificity at diagnosis in posttransplant lymphoproliferative disorders (PTLDs). However, little is known about the performance of interim and end of treatment (EOT) PET in PTLD patients with regards to response assessment, relapse prediction and outcome. Methods: We performed a single-center retrospective study in which we analyzed consecutive patients diagnosed with CD20-positive PTLD after solid organ transplantation between 2008 and 2017, who all received risk-stratified sequential treatment according to the PTLD-1 phase II trial. Interim and EOT PET studies were scored according to the Deauville criteria. Results: Forty-one patients were included with median follow-up of 41.5 months (range 1-108). Positive and negative predictive values for disease recurrence were 13% and 85% for interim and 33% and 87% for EOT PET, respectively. There was no significant difference in overall survival, progression-free survival nor time to progression between negative versus positive patients on interim and EOT scans. Conclusions: Negative interim and/or negative end of treatment PET identify PTLD patients with low risk of disease recurrence.

The use of Deauville 5-point score could reduce the risk of false-positive fluorodeoxyglucose-positron emission tomography in the posttherapy evaluation of patients with primary bone lymphomas

Primary bone lymphoma (PBL) is a rare disease. Little is reported about response evaluation procedures in these patients. Our aim was to evaluate response to therapy according to fluorodeoxyglucose-positron emission tomography (FDG-PET) results, and in particular to test the Deauville 5-point scale as compared to the visual evaluation of FDG-PET scans in PBL. In this single-center study, we diagnosed 31 consecutive patients with PBL, of which 24 were evaluated with end-of-treatment FDG-PET. Patients' ages ranged from 19 to 82 years. Six patients were treated with chemotherapy, 24 with chemotherapy and radiotherapy, and one patient with radiotherapy alone. Six patients were affected by a pathological fracture. Four patients died within the range of 3 to 36 months after diagnosis. The average follow-up of the remaining patients was 70 (24–173) months. Overall survival was 87% at 5 years. The only positive prognostic factor was complete remission after chemotherapy. According to visual criteria, end-of-treatment FDG-PET was evaluated in 24 patients and it was positive in 11 (46%) and negative in 13 patients. We organized a retrospective central-blinded revision of end-of-therapy FDG-PET scans using the 5-point Deauville Score (DS). We reviewed 17 out of 24 patients and obtained the following results: at the end of therapy, 12 patients with DS score 2, three patients with DS score 3, one patient with DS score 4, and none with DS score 5. Considering that all the 24 patients achieved complete remission after treatment, visual interpretation produced 11/24 false-positive results, and DS interpretation produced 1/17 false-positive results, thus significantly reducing the number of false positives. In PBL, the final evaluation at the end of therapy with FDG-PET should be evaluated using Deauville 5-point scale in order to significantly reduce the risk of false-positive scans.

Correlation between early 18F-FDG PET/CT response to BRAF and MEK inhibition and survival in patients with BRAF-mutant metastatic melanoma

PURPOSE

Metabolic response to treatment measured by fluorine-18 fluorodeoxyglucose ((18)F-FDG) PET has prognostic implications in many cancers. This study investigated the association between survival and early changes on (18)F-FDG PET/computed tomography (CT) for patients with BRAF-mutant melanoma receiving combined BRAF and MEK inhibition therapy.

MATERIALS AND METHODS

Overall, 24 patients with advanced BRAF-mutant melanoma were included. Patients were treated with a BRAF inhibitor (vemurafenib or dabrafenib) and a MEK inhibitor (cobimetinib or trametinib), and were imaged at baseline and shortly thereafter with (18)F-FDG PET/CT. Each scan yielded two values of maximum standardized uptake value (SUVmax): one for the most metabolically active focus and one for the least responsive focus. Short-term treatment response was assessed by evaluating the target lesions using the EROTC criteria. A Cox proportional hazards model was used to examine associations between overall survival (OS) and progression-free survival (PFS) and changes in SUVmax.

RESULTS

The mean time to follow-up (18)F-FDG PET/CT was 26 days. At follow-up, two patients achieved a complete response. For the most metabolically active focus, 22 patients showed a partial response. For the least responsive focus, 18 patients showed a partial response, two had stable disease, and two had progressive disease.A total of 16 patients were alive at the end of the study. For the most metabolically active tumor, no association was observed between changes in SUVmax and OS (P=0.73) or PFS (P=0.17). For the least responsive tumor, change in SUVmax was associated with PFS [hazard ratio (HR)=1.34, 95% confidence interval (CI): 1.06-1.71, P=0.01], but not OS (P=0.52). The ECOG score was associated with OS (HR=11.81, 95% CI: 1.42-97.60, P=0.02) and PFS (HR=24.72, 95% CI: 3.23-189.42, P=0.002).

CONCLUSION

Change in SUVmax for the least responsive tumor and baseline functional performance may be useful prognostic indicators for PFS in patients with BRAF-mutant melanoma.

Accuracy of whole-body MRI in the assessment of splenic involvement in lymphoma

BACKGROUND

Accurate evaluation of the spleen is an important component of staging lymphoma, because this may have prognostic and therapeutic implications.

PURPOSE

To determine the diagnostic value of whole-body magnetic resonance imaging (MRI), including diffusion-weighted imaging (whole-body MRI-DWI) in the detection of splenic involvement in lymphoma.

MATERIAL AND METHODS

This IRB approved, prospective multicenter study included a total of 107 patients with newly diagnosed, histologically proven lymphoma who underwent 1.5 T whole-body MRI-DWI and FDG-PET/CT. Whole-body MRI-DWI and FDG-PET/CT were independently evaluated by a radiologist and a nuclear medicine physician, in a blinded manner. Splenic involvement at MRI was defined as splenic index > 725 cm(3) or discrete nodules. At FDG-PET/CT splenic involvement was defined as splenic uptake greater than liver uptake or hypodense nodules at contrast-enhanced CT. FDG-PET/CT augmented with follow-up imaging after treatment was used as reference standard.

RESULTS

Splenic involvement was detected with FDG-PET/CT in 21 patients, all demonstrating response to treatment. The sensitivity, specificity, positive predictive value, and negative predictive value of whole-body MRI-DWI for the detection of splenic involvement were 85.7 %, 96.5 %, 85.7%, and 96.5%, respectively. Three out of six discrepancies were related to suboptimal criterion of splenic size used with whole-body MRI-DWI versus the size-independent FDG uptake.

CONCLUSION

Whole-body MRI-DWI is reasonably accurate in the detection of splenic lymphomatous involvement.

Fluorine-18 fluorodeoxyglucose PET-CT for extranodal staging of non-Hodgkin and Hodgkin lymphoma

PURPOSE

We aimed to evaluate the role of fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) involving care-dose unenhanced CT to detect extranodal involvement in patients with non-Hodgkin and Hodgkin lymphoma.

MATERIALS AND METHODS

Lymphoma patients (35 Hodgkin lymphoma, 75 non-Hodgkin lymphoma) who were referred for 18F-FDG PET-CT imaging, following a diagnostic contrast-enhanced CT (CE-CT) performed within the last month, were included in our study. A total of 129 PET-CT images, and all radiologic, clinical, and pathological records of these patients were retrospectively reviewed.

RESULTS

In total, 137 hypermetabolic extranodal infiltration sites were detected by 18F-FDG PET-CT in 62 of 110 patients. There were no positive findings by CE-CT that reflected organ involvement in 40 of 137 18F-FDG-positive sites. The κ statistics revealed fair agreement between PET-CT and CE-CT for the detection of extranodal involvement (κ=0.60). The organs showing a disagreement between the two modalities were the spleen, bone marrow, bone, and thyroid and prostate glands. In all lesions that were negative at CE-CT, there was a diffuse 18F-FDG uptake pattern in the PET-CT images. The frequency of extranodal involvement was 51% and 58% in Hodgkin and non-Hodgkin lymphoma patients, respectively. There was a high positive correlation between the maximum standardized uptake values of the highest 18F-FDG-accumulating lymph nodes and extranodal sites (r=0.67) in patients with nodal and extranodal involvement.

CONCLUSION

18F-FDG PET-CT is a more effective technique than CE-CT for the evaluation of extranodal involvement in Hodgkin and non-Hodgkin lymphoma patients. PET-CT has a significant advantage for the diagnosis of diffusely infiltrating organs without mass lesions or contrast enhancement compared to CE-CT.

Whole-body MRI for initial staging of paediatric lymphoma: prospective comparison to an FDG-PET/CT-based reference standard

OBJECTIVE

To compare whole-body MRI, including diffusion-weighted imaging (whole-body MRI-DWI), with FDG-PET/CT for staging newly diagnosed paediatric lymphoma.

METHODS

A total of 36 children with newly diagnosed lymphoma prospectively underwent both whole-body MRI-DWI and FDG-PET/CT. Whole-body MRI-DWI was successfully performed in 33 patients (mean age 13.9 years). Whole-body MRI-DWI was independently evaluated by two blinded observers. After consensus reading, an unblinded expert panel evaluated the discrepant findings between whole-body MRI-DWI and FDG-PET/CT and used bone marrow biopsy, other imaging data and clinical information to derive an FDG-PET/CT-based reference standard.

RESULTS

Interobserver agreement of whole-body MRI-DWI was good [all nodal sites together (κ = 0.79); all extranodal sites together (κ = 0.69)]. There was very good agreement between the consensus whole-body MRI-DWI- and FDG-PET/CT-based reference standard for nodal (κ = 0.91) and extranodal (κ = 0.94) staging. The sensitivity and specificity of consensus whole-body MRI-DWI were 93 % and 98 % for nodal staging and 89 % and 100 % for extranodal staging, respectively. Following removal of MRI reader errors, the disease stage according to whole-body MRI-DWI agreed with the reference standard in 28 of 33 patients.

CONCLUSIONS

Our results indicate that whole-body MRI-DWI is feasible for staging paediatric lymphoma and could potentially serve as a good radiation-free alternative to FDG-PET/CT.

KEYPOINTS

• Accurate staging is important for treatment planning and assessing prognosis • Whole-body MRI-DWI could be a good radiation-free alternative to FDG-PET/CT • Interobserver agreement of whole-body MRI-DWI is good • Agreement between whole-body MRI and the FDG-PET/CT reference standard is good • Most discrepancies were caused by suboptimal accuracy of size measurements on MRI.

(18)F-FDG PET in Patients with Primary Systemic Anaplastic Large Cell Lymphoma: Differential Features According to Expression of Anaplastic Lymphoma Kinase

PURPOSE

Primary systemic anaplastic large cell lymphoma (ALCL) is divided into two entities according to the expression of anaplastic lymphoma kinase (ALK). We investigated (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) findings in primary systemic ALCL according to ALK expression.

METHODS

Thirty-seven patients who had baseline PET before CHOP (cyclophosphamide, doxorubicin, vincristine and prednisolone)-based chemotherapy were enrolled. Among them, patients who underwent interim and/or post-therapy PET were further investigated for the treatment response and survival analysis. Baseline PET was analyzed visually and semi-quantitatively using peakSUV, and interim and post-therapy PETs were visually analyzed.

RESULTS

All cases were (18)F-FDG-avid on baseline PET. The peakSUV of ALK-positive ALCL (n = 16, 18.7 ± 10.5) was higher than that of ALK-negative ALCL (n = 21, 10.0 ± 4.9) (P = 0.006). In ALK-negative ALCL, complete response (CR) rate in negative-interim PET was higher than positive-interim PET (100 % vs 37.5 %, P = 0.02); however, there was no such difference in ALK-positive ALCL (100 % vs 75 %, P = 0.19). The 3-year progression-free survival (PFS) was not significantly different between ALK-positive and ALK-negative ALCL (72.7 % vs 47.6 %, P = 0.34). In ALK-negative ALCL, negative interim and post-therapy PET patients had better 3-year PFS than positive interim (83.3 % vs 25.0 %, P = 0.06) and post-therapy PET patients (70.0 % vs 20.0 %, P = 0.04). In contrast, ALK-positive ALCL had no such differences between PFS and PET results.

CONCLUSIONS

On baseline PET, all cases showed (18)F-FDG-avidity, and ALK expression was related to higher (18)F-FDG uptake. ALK-positive patients tend to have better PFS than ALK-negative patients. Negative-interim PET was a good indicator of CR, and interim or post-therapy PET was helpful for predicting the prognosis only in the ALK-negative group.

Primary gastric lymphoma: utility of 18F-fluorodeoxyglucose positron emission tomography-computed tomography for detecting relapse after treatment

The purpose of this study was to evaluate the role of 18F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography-computed tomography (PET-CT) in detecting relapse in patients with primary gastric lymphoma (PGL) post-treatment. Data of 39 previously treated patients with PGL (age: 50.3 ± 13.8 years; male: 24) who underwent 71 (18)F-FDG PET-CT studies for suspected relapse (n = 53) or routine follow-up (n = 18) were retrospectively evaluated. PET-CT images were evaluated both qualitatively and quantitatively (standardized uptake value [SUVmax]). A combination of clinical/imaging follow-up, endoscopy and/or histopathology was taken as the reference standard. The per patient based sensitivity of PET-CT was 96%, specificity 91% and accuracy 93%. The lymph node was the commonest site of relapse on PET-CT. Mean lesion SUVmax was 5.9 ± 3.1 (2.3-13.6). Accuracy was similar in suspected relapse and routine follow-up groups (90.5% vs. 100%; p = 0.409). Based on the data, (18)F-FDG PET-CT appears to be highly accurate for the detection of relapse in patients with PGL post-treatment.

Imaging-pathologic correlation of diseases in the axilla

OBJECTIVE

This article reviews the imaging and histopathologic findings of various axillary diseases and suggests management guidelines for radiologists based on imaging findings with clinical correlation.

CONCLUSION

Although axillary diseases may reveal nonspecific imaging findings, a knowledge of the characteristic radiologic manifestations of specific diseases according to anatomic origin (nodal, accessory breast, adipocytic, fibrous, nerve, vascular, stromal, and dermal) and postsurgical lesions aids in establishing an appropriate differential diagnosis and determining whether intervention is necessary.

Enhancement characteristics of retroperitoneal lymphomatous lymph nodes

BACKGROUND

Previous studies of CT enhancement of lymphomatous lymph nodes (LLN) of the neck and the mediastinum showed that the LLN had lower enhancement values than normal lymph nodes.

PURPOSE

To elucidate the contrast medium enhancement curves of LLN in the retroperitoneum by comparing the curves of LLN with those of normal lymph nodes, to test whether differences between these curves could be of diagnostic value, and to compare the present enhancement curves of LLN of the retroperitoneum with the curves of LLN of the neck and the mediastinum from previous similar investigations.

MATERIAL AND METHODS

Twenty-eight consecutive patients with LLN of the retroperitoneum (three with Hodgkin's lymphoma [HL]) and 21 control patients with sarcomas and thus presumably normal retroperitoneal nodes underwent dynamic CT examinations. The previous, similar investigation of lymph nodes of the neck comprised 28 patients with LLN and the investigation of mediastinal lymph nodes comprised 24 patients with LLN.

RESULTS

The enhancement curves of the retroperitoneal LLN had significantly lower attenuation than those of the retroperitoneal control nodes. A combination of peak contrast value and time to peak adjusted to total body weight yielded a diagnostic accuracy which at the best showed a sensitivity of 90.5% with a specificity of 82.6%. The LLN of the retroperitoneum had higher attenuation values than corresponding nodes of the mediastinum but no significant difference was found between LLN of the retroperitoneum and LLN of the neck in previous similar investigations.

CONCLUSION

The comparison of enhancement curves of retroperitoneal LLN with retroperitoneal control nodes showed a marked similarity with and substantiates our previous findings in lymph nodes of the neck and of the mediastinum. The best diagnostic accuracy was achieved by combining the parameters peak contrast value and time to peak and adjusting these values to the body weight. Peak enhancement of the retroperitoneal LLN was higher and arrived earlier than that of the mediastinal nodes from the previous investigation.

30 years of lymph node pathology: biomarkers and other advances

Over the last 30 years there has been a massive change in both the clinical and pathologic aspects of malignant lymphomas. Pathologists are now able to evaluate cellular phenotypes and lineages of tumor cells using a wide variety of biomarkers and molecular techniques. The ability to identify tumor cell phenotypes has revolutionized the classification of lymphomas, leading to an internationally agreed system based on the reliable recognition of specific clinico-pathologic entities. The World Health Organization classification combines clinical features, histomorphology, immunohistochemistry, and molecular and genetic marker data to precisely categorize lymphomas. On the clinical front the increasing use of needle core biopsies has made it easier and quicker to obtain tissue samples, and the development of (18)F-fluorodeoxyglucose positron emission tomography has revolutionized the assessment of patients both at presentation and after treatment. To improve overall outcomes for lymphoma patients there have been advances in the UK organization of cancer services. Cancer networks have been established, often with network multidisciplinary team meetings, and new diagnoses of lymphoma are reviewed on a network basis by pathologists specializing in the field. National and supranational quality control systems are in place for immunohistochemistry and for molecular techniques and multicenter clinical trials provide information about the efficacy of treatment regimens. The outcome of these advances is that a patient presenting in 2012 with suspected lymphoma can expect to be biopsied rapidly, to receive an accurate pathologic diagnosis by an expert hematopathologist, which will include prognostic marker information, and to have comprehensive disease assessment and discussion by a multidisciplinary team before embarking on the most appropriate treatment for his or her clinical situation.

[¹⁸F]fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography imaging in oncology: initial staging and evaluation of cancer therapy

Positron emission tomography (PET) with [¹⁸F]fluoro-2-deoxy-D-glucose (FDG) has proven to be a valuable diagnostic modality in various diseases. Its accuracy has been improved with the hybrid PET/computed tomography (CT) technique because of precise anatomic location of areas of abnormal FDG accumulation. This integrated PET/CT modality has been widely adopted, particularly in oncology. This paper reviews the role of FDG-PET/CT imaging in breast cancer, non-small-cell lung cancer, colorectal cancer, head and neck cancer as well as lymphoma on the basis of recent key articles. Special attention is paid to preoperative diagnostic workup, evaluation of treatment response and survival prognosis. Experience from specialized centers indicates that there is strong evidence for the clinical effectiveness of FDG-PET/CT in staging, restaging and the prediction of response to therapy in the above-mentioned malignancies. It is concluded that this imaging modality contributes considerably to improved patient management and paves the way to personalize cancer treatment in a cost-effective way.

Rare case of Primary Pulmonary Extranodal Non-Hodgkin's Lymphoma in a Patient with Sjogren's Syndrome: Role of FDG-PET/CT in the Initial Staging and Evaluating Response to Treatment

A 64-year old woman with a long standing Sjogren's syndrome was undergoing evaluation for renal transplant surgery when two pulmonary opacities were detected on chest CT. Subsequent biopsy revealed extranodal marginal B-cell non-Hodgkin's lymphoma (NHL). An FDG-PET/CT scan was then performed which demonstrated isolated FDG avid pulmonary involvement. After therapy, FDG-PET/CT scans showed good response to treatment with near complete resolution of FDG avidity. This rare case illustrates the rare pulmonary manifestation of extranodal lymphoma in a patient with Sjogren's syndrome and emphasizes the value of FDG PET/CT in the initial staging and evaluation of response to treatment, which has not previously been published.

CONFLICT OF INTEREST

None declared.

Prognostic value of quantitative parameters derived on initial staging 18F-fluorodeoxyglucose positron emission tomography/computed tomography in patients with high-grade non-Hodgkin's lymphoma

OBJECTIVES

This study was carried out to evaluate the role of quantitative parameters in staging PET in predicting prognosis in patients with high-grade non-Hodgkin's lymphoma (NHL).

METHODS

A total of 51 histopathologically proven high-grade NHL patients treated with conventional chemotherapy regimens were included in the study. Total lesion glycolysis (TLG) and functional volumes (FVs) were defined as per the PET Response Criteria in Solid Tumors (PERCIST) criteria. All patients were followed up for a minimum period of 1 year or until an event, whichever occurred earlier.

RESULTS

Of the four semiquantitative parameters studied, SUV max and SUV mean did not show a statistically significant correlation with progression-free survival or overall survival, whereas TLG and FV showed a weak but statistically significant negative correlation. Using the receiver operating characteristic curve analysis, optimal cut-offs were derived for FV and TLG to predict progression and death. Using the cut-off values of 416 cm3 and 3340 g for FV and TLG, respectively, a statistically significant difference in progression-free survival and overall survival was obtained in the groups with FV and TLG above and below the threshold. On multivariate analysis of all the conventional prognostic factors and TLG more than 3340 and FV more than 416 cm3, only age greater than 60 years (P=0.013) and FV more than 416 cm3 (P=0.012) were found to be independently associated with disease progression.

CONCLUSION

Our results indicate that FV and TLG in staging PET/CT could be useful indices in predicting outcomes in patients with high-grade NHL treated with standard first-line chemotherapy regimens.

Usefulness of (18)F-FDG PET/CT for the Evaluation of Bone Marrow Involvement in Patients with High-Grade Non-Hodgkin's Lymphoma

PURPOSE

To assess the usefulness of (18)F-fluorodeoxyglucose PET/CT in the detection of bone marrow (BM) involvement of high-grade non-Hodgkin's lymphoma (NHL).

METHODS

One hundred twenty patients with newly diagnosed diffuse large B-cell lymphoma or peripheral T-cell lymphoma between January 2007 and June 2011, who received BM trephine biopsy and (18)F-FDG PET/CT before chemotherapy, were included in this retrospective study. We reviewed their (18)F-FDG PET/CT images and bone marrow biopsy (BMB) results. After reviewing the images, we reviewed the medical records and radiological findings of interesting patients.

RESULTS

There were 23 (18)F-FDG PET/CT scans in which the marrow was considered to be abnormal (either positive or equivocal), and 97 (18)F-FDG PET/CT scans were regarded as having negative FDG uptake. Of 120 patients, 100 (83.3 %) had a concordant result of BM interpretation between (18)F-FDG PET/CT and BMB, and the remaining 20 patients had discordant results. Among 23 patients with either positive or equivocal (18)F-FDG PET/CT scans, 1 of 12 patients with 'positive' (18)F-FDG PET/CT had a lymphomatous involvement on BMB. In contrast, 10 of 11 patients with 'equivocal' BM hypermetabolism were reported as having positive involvement by BMB. Patients with abnormal (18)F-FDG PET/CT had significantly higher mSUVhighest than those with normal FDG-PET/CT.

CONCLUSIONS

(18)F-FDG PET/CT and BMB are complementary techniques in assessing the presence of BM involvement in patients with high-grade NHL. The increasing availability of (18)F-FDG PET/CT will raise the need for additional biopsy for FDG-avid lesions, especially in patients with negative standard BMBs. (18)F-FDG PET/CT can be useful as a decision-making tool for determining whether to perform a standard BMB or targeted biopsy to the FDG-avid lesion as an initial staging procedure. A direct bone biopsy for FDGpositive bone lesions should be included in staging guidelines in future. In (18)F-FDG PET/CT-negative cases, BMB is still a powerful procedure, but BMB alone is insufficient for full evaluation of BM.

The accuracy of positron emission tomography in the detection of posttransplant lymphoproliferative disorder

We investigated sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-fluorodeoxyglucose-positron emission tomography in 170 cases with suspected or biopsy-proven posttransplant lymphoproliferative disorder. All solid organ and hematopoietic stem cell transplant recipients who underwent an 18F-fluorodeoxyglucose-positron emission tomography scan between 2003 and 2010 in our center for the indication posttransplant lymphoproliferative disorder, were retrospectively reviewed and results were compared with tissue biopsy whenever possible. One hundred and seventy positron emission tomography scans in 150 patients were eligible for evaluation. In 45 cases, the patient had a biopsy-confirmed posttransplant lymphoproliferative disorder before positron emission tomography scanning and positron emission tomography was performed for staging purposes. In the remaining 125 cases, positron emission tomography was performed to differentiate between posttransplant lymphoproliferative disorder and other diseases. 18F-fluorodeoxyglucose-uptake was quantitatively expressed by calculation of maximum and mean standardized uptake value in the most intense lesion or, in the absence of attenuation corrected positron emission tomography scans, by comparing uptake in target lesion to liver and mediastinal uptake. We found an overall sensitivity of 89%, specificity of 89%, positive predictive value of 91% and negative predictive value of 87% for posttransplant lymphoproliferative disorder detection by 18F-fluorodeoxyglucose-positron emission tomography. In a subanalysis of the 125 scans performed for differentiating posttransplant lymphoproliferative disorder from other diseases, sensitivity, specificity, positive predictive value and negative predictive value were 90%, 89%, 85% and 93%, respectively. 18F-fluorodeoxyglucose-uptake in posttransplant lymphoproliferative disorder was generally high with a median mean and maximum standardized uptake value of 9.0 (range 2.0-18.6) and 17.4 (range 2.6-26.4). Posttransplant lymphoproliferative disorder often had an atypical presentation on positron emission tomography with high incidence of extranodal involvement. In conclusion, from these data, we can conclude that 18F-fluorodeoxyglucose-positron emission tomography is highly sensitive for detecting posttransplant lymphoproliferative disorder and has an excellent ability to differentiate posttransplant lymphoproliferative disorder from non-malignant diseases.

[Management of anterior mediastinal masses in adults]

The discovery of an anterior mediastinal mass requires careful management with specific consideration of the pathology. More than 50% of all mediastinal masses seen in adults are in the anterior mediastinum. The most frequent diagnoses are thymoma, lymphoma, teratoma and benign thyroid tumours. 60% of cases are malignant. Often the clinical and radiological findings do not allow a definitive diagnosis and a histological diagnosis is often required to select the optimal treatment modality. The choice of biopsy technique depends on the localization of the lesion, clinical factors, and the availability of special techniques and equipment. Biopsy may be obtained by trans-thoracic puncture under computed tomography or ultrasound guidance, or by a surgical approach (mediastinotomy or thoracoscopy).

SAR3419: an anti-CD19-Maytansinoid Immunoconjugate for the treatment of B-cell malignancies

SAR3419 is a novel anti-CD19 humanized monoclonal antibody conjugated to a maytansine derivate through a cleavable linker for the treatment of B-cell malignancies. SAR3419 combines the strengths of a high-potency tubulin inhibitor and the exquisite B-cell selectivity of an anti-CD19 antibody. The internalization and processing of SAR3419, following its binding at the surface of CD19-positive human lymphoma cell lines and xenograft models, release active metabolites that trigger cell-cycle arrest and apoptosis, leading to cell death and tumor regression. SAR3419 has also been shown to be active in different lymphoma xenograft models, including aggressive diffuse large B-cell lymphoma, resulting in complete regressions and tumor-free survival. In these models, the activity of SAR3419 compared favorably with rituximab and lymphoma standard of care chemotherapy. Two phase I trials with 2 different schedules of SAR3419 as a single agent were conducted in refractory/relapsed B-cell non-Hodgkin lymphoma. Activity was reported in both schedules, in heavily pretreated patients of both follicular and diffuse large B-cell lymphoma subtypes, with a notable lack of significant hematological toxicity, validating SAR3419 as an effective antibody-drug conjugate and opening opportunities in the future. Numerous B-cell-specific anti-CD19 biologics are available to treat B-cell non-Hodgkin lymphoma, and early phase I results obtained with SAR3419 suggest that it is a promising candidate for further development in this disease. In addition, thanks to the broad expression of CD19, SAR3419 may provide treatment options for B-cell leukemias that are often CD20-negative.

Non-Hodgkin's lymphoma of the testicle and bilateral adrenals detected by (18)F-FDG PET/CT

Lymphoma, particularly non-Hodgkin's lymphoma, may occur in sites other than the lymph nodes, i.e., extranodal lymphoma, which occurs in approximately 40% of total lymphoma cases. However, simultaneous detection of multiple extranodal involvements at presentation is quite uncommon. Here, we report a rare case of a 55-year-old Chinese man with non-Hodgkin's lymphoma of the left testicle and bilateral adrenals as determined by (18)F-FDG PET/CT imaging. FDG PET/ CT has been successfully employed for lymphoma diagnosis, initial staging, restaging and therapy follow-up. It is useful for assessing both nodal and extranodal involvements. In the present case of lymphoma with involvement of the testicle and bilateral adrenals, (18)F-FDG PET/CT played an important role in the diagnosis and assessment of therapeutic response.

¹⁸F-FDG-PET/CT for detection of extramedullary acute myeloid leukemia

Myeloid sarcoma in acute myeloid leukemia has been clearly defined by the World Health Organization but studies regarding the prevalence and the prognostic impact of extramedullary acute myeloid leukemia have not been conducted. We performed (18)Fluoro-deoxy-Glucose Positron Emission Tomography/Computed Tomography scans in 10 patients with de novo and relapsed acute myeloid leukemia and histologically proven extramedullary disease. The scans were able to detect the known extramedullary lesions in 9 out of 10 patients (90%). Furthermore, additional extramedullary sites were detected in 6 patients (60%). Thus, it is possible to identify known and clinically undetectable extramedullary manifestations of acute myeloid leukemia. Since most of these patients relapsed within a short period of time after initiation of therapy or had refractory disease, the detection of extramedullary disease with (18)Fluoro-deoxy-Glucose Positron Emission Tomography/Computed Tomography might be helpful in the development of individual treatment algorithms for these high-risk patients.