Utility of 18F-FDG PET/CT for staging NK/T-cell lymphomas

18F-FDG PET/CT in the diagnosis and treatment of atypical extensive skin lesions in extranodal natural killer/T-cell lymphoma, nasal type: a case report

We report a case of a 60-year-old man who developed scattered erythema and papules on his left upper limb without any apparent cause 6 months ago. Initially, the patient underwent evaluations for various dermatological conditions, including eczema and psoriasis, while also being assessed for potential malignancies such as cutaneous lymphoma or sarcoidosis, but no definitive diagnosis was made. Over time, the patient's symptoms progressed, presenting as generalized erythema, papules, localized itching, and pain. A histopathological examination of the lesions diagnosed it as extranodal NK/T-cell lymphoma, nasal type (ENKTCL-NT). Subsequently, the patient was referred for staging via 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT), which revealed a widespread pattern of metabolically active lesions primarily affecting the skin and subcutaneous tissue of the limbs and buttocks. The patient received sequential treatment with P-GEMOX (gemcitabine, oxaliplatin, and pegaspargase) and underwent clinical examination and follow-up whole-body 18F-FDG PET/CT after six treatment cycles. The post-treatment PET/CT showed no abnormal 18F-FDG uptake in the nasal cavity or skin, confirming clinical complete remission. Our case highlights the significant role of 18F-FDG PET/CT in clinical practice for initial staging and treatment response assessment of ENKTCL-NT.

Comparison of 18F-FDG PET/CT and conventional methods in diagnosing extranodal natural killer/T-cell lymphoma

Background

The utility of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in natural killer (NK)/T-cell lymphoma patients is yet to be established. The aim of this study was to investigate the role of PET/CT scanning in detecting NK/T-cell lymphoma.

Methods

We analyzed the PET/CT imaging characteristics of 38 patients with a primary diagnosis of NK/T-cell lymphoma and also compared the ability of PET/CT to detect tumor lesions with conventional methods (CMs) (physical examination, computed tomography (CT) with intravenous contrast, magnetic resonance imaging (MRI), biopsies from primary sites, and bone marrow examinations)and their impact on staging and treatment options. Biopsy and clinical follow-up (including imaging) are the gold standard for diagnosis.

Results

We analyzed PET/CT images of NK/T-cell lymphomas. We found that most of the primary lesions were located in the nasal cavity, with the sinuses and the posterior pharyngeal wall being the most common sites of adjacent invasion. The majority of cases involved cervical lymph nodes, and the distribution of affected lymph nodes between the cervical and extra-cervical regions was random. There was no discernible pattern to the locations of affected tissues and organs across the body. In total, 219 lesions (including 81 nodal lesions and 138 extranodal lesions) tested positive for malignancy. The number of positive lymph node lesions detected by PET/CT and CMs was 79 (97.5 %) and 62 (76.5 %), respectively (P = 0.004). There were 53 (96.4 %) and 46 (83.6 %) cervical lymph nodes detected (P = 0.008), 26 (100 %) and 16 (61.5 %) other lymph nodes detected (P = 0.041)), respectively. The number of positive extranodal lesions detected by PET/CT and CMs was 137 (99.3 %) and 98 (71.0 %), respectively (P = 0.01), and there were no discernible differences in the upper respiratory tract. PET/CT outperformed CMs in the detection of malignant lesions by a significant margin, detecting 79 (98.8 %) extranodal lesions compared to 45 (56.3 %) by CMs (P = 0.034). PET/CT results changed the initial staging in 15.8 % of cases and the treatment plan in 10.5 % of patients.

Conclusion

Our findings indicate that 18F-FDG PET/CT scanning is crucial in identifying tumor lesions, determining staging, and devising treatment strategies for individuals diagnosed with NK/T-cell lymphoma.

PET/CT Imaging in Treatment Planning and Surveillance of Sinonasal Neoplasms

Sinonasal cancers are uncommon malignancies with a generally unfavorable prognosis, often presenting at an advanced stage. Their high rate of recurrence supports close imaging surveillance and the utilization of functional imaging techniques. Whole-body 18F-FDG PET/CT has very high sensitivity for the diagnosis of sinonasal malignancies and can also be used as a "metabolic biopsy" in the characterization of some of the more common subgroups of these tumors, though due to overlap in uptake, histological confirmation is still needed. For certain tumor types, radiotracers, such as 11C-choline, and radiolabeled somatostatin analogs, including 68Ga-DOTATATE/DOTATOC, have proven useful in treatment planning and surveillance. Although serial scans for posttreatment surveillance allow the detection of subclinical lesions, the optimal schedule and efficacy in terms of survival are yet to be determined. Pitfalls of 18F-FDG, such as post-surgical and post-radiotherapy crusting and inflammation, may cause false-positive hypermetabolism in the absence of relapse.

Multimodality imaging evaluation of primary testicular extranodal natural killer/T-cell lymphoma: two case reports

Background

Extranodal natural killer/T-cell lymphoma (ENKTCL) is a distinct pathological entity and accounts for ~10% of T-cell lymphomas. The histological features of ENKTCL include angiodestruction and coagulative necrosis and the association with EBV infection. ENKTCL is typically aggressive and mainly affects the nasal cavity and nasopharyngeal region. However, some patients can present with distant nodal or extranodal involvement such as the Waldeyer ring, gastrointestinal tract, genitourinary organs, lung, thyroid, skin, and testes. Compared to ENKTCL of nasal type, primary testicular ENKTCL is very rare and has a lower age of onset and faster clinical progression, with tumor cell dissemination occurring early in the disease.

Case report

Case 1: A 23-year-old man presented with 1 month of right testicular pain and swelling. Enhancement CT revealed increased density in the right testis, uneven increased enhancement, discontinuity of the local envelope, and multiple trophoblastic vessels in the arterial phase. Testicular ENKTCL was diagnosed by post-operative pathology. The patient underwent a follow-up ¹⁸F-FDG PET/CT imaging 1 month later and found elevated metabolism in the bilateral nasal, left testicular, and right inguinal lymph nodes. Unfortunately, the patient received no further treatment and died 6 months later. Case 2: A 2-year-old male child presented with an enlarged right testicle, MRI showed a mass in the right epididymis and testicular area, which showed low signal on T1WI, high signal on T2WI and DWI, and low signal on ADC. Meanwhile, CT showed soft tissue in the lower lobe of the left lung and multiple high-density nodules of varying sizes in both lungs. Based on the post-operative pathology, the lesion was diagnosed with primary testicular ENKTCL. The pulmonary lesion was diagnosed as hemophagocytic lymphohistiocytosis associated with EBV infection. The child was given SMILE chemotherapy, but pancreatitis was induced during chemotherapy, then he died 5 months later after chemotherapy.

Conclusion

Primary testicular ENKTCL is very rare in clinical practice, typically presenting as a painful testicular mass, which can mimic inflammatory lesions and cause diagnostic challenges. ¹⁸F-FDG PET/CT plays pivotal roles in the diagnosis, staging, evaluation of treatment outcomes and prognosis evaluation in patients with testicular ENKTCL, and it is helpful to assist clinical practice to better formulate individualized treatment plans.

Extranodal NK/T-Cell Lymphoma With Widespread Cutaneous and Subcutaneous Involvement on 18 F-FDG PET/CT

ABSTRACT

Nasal-type extranodal natural killer/T-cell lymphoma is an aggressive rare type of lymphoma that mostly affects the nasal cavity and adjacent areas. However, some patients can present with distant nodal or extranodal involvement including the Waldeyer ring, gastrointestinal tract, genitourinary organs, lung, thyroid, skin, or adrenal glands. Herein, we present a unique case of extranodal natural killer/T-cell lymphoma with widespread cutaneous and subcutaneous involvement on 18 F-FDG PET/CT.

Dynamic evaluation of the prognostic value of 18F-FDG PET/CT in extranodal NK/T-cell lymphoma, nasal type

Extranodal natural killer/T-cell lymphoma, nasal-type (ENKTL) is a type of rare and distinct entity of non-Hodgkin lymphoma with poor prognosis. It is important to evaluate the early treatment response accurately to decide further treatment strategy. ¹⁸F-FDG PET/CT plays an important role in response evaluation and prognostic prediction in some kinds of lymphomas. However, data available regarding patients with ENKTL are limited. Thus, in this prospective study, we analyzed the prognostic value of ¹⁸F-FDG PET/CT in ENKTL. Thirty-four patients with newly diagnosed ENKTL were enrolled in this phase 2 study (NCT02825147, July 7, 2016). The patients received pre-, mid-, and end-treatment ¹⁸F-FDG PET/CT scans. Deauville score (DS), maximal standardized uptake values (SUVmax), and the change in SUVmax (ΔSUVmax) were recorded for response assessment. The median follow-up period was 42.2 months. The 2-year overall survival (OS) and progression-free survival (PFS) were 82.4% and 73.5%, respectively. Univariate analysis revealed that Ann Arbor stage (P < 0.002), mid-treatment DS (P = 0.005), mid-SUVmax (P = 0.001), mid-∆SUVmax (P = 0.004), end-treatment DS (P < 0.001), and end-SUVmax (P = 0.014) were prognostic factors for OS. Ann Arbor stage (P = 0.001), mid-treatment DS (P = 0.008), mid-SUVmax (P = 0.029), mid-∆SUVmax (P < 0.001), and end-treatment DS (P =0.021) were of prognostic significance for PFS. Multivariate analysis showed that mid-SUVmax (P = 0.042) and DS at the middle (P = 0.050) and end (P = 0.044) of treatment were significant independent predictors of PFS. ¹⁸F-FDG PET/CT is useful for predicting the prognosis of ENKTL.

Weakly supervised deep learning for determining the prognostic value of 18F-FDG PET/CT in extranodal natural killer/T cell lymphoma, nasal type

Purpose

To develop a weakly supervised deep learning (WSDL) method that could utilize incomplete/missing survival data to predict the prognosis of extranodal natural killer/T cell lymphoma, nasal type (ENKTL) based on pretreatment ¹⁸F-FDG PET/CT results.

Methods

One hundred and sixty-seven patients with ENKTL who underwent pretreatment ¹⁸F-FDG PET/CT were retrospectively collected. Eighty-four patients were followed up for at least 2 years (training set = 64, test set = 20). A WSDL method was developed to enable the integration of the remaining 83 patients with incomplete/missing follow-up information in the training set. To test generalization, these data were derived from three types of scanners. Prediction similarity index (PSI) was derived from deep learning features of images. Its discriminative ability was calculated and compared with that of a conventional deep learning (CDL) method. Univariate and multivariate analyses helped explore the significance of PSI and clinical features.

Results

PSI achieved area under the curve scores of 0.9858 and 0.9946 (training set) and 0.8750 and 0.7344 (test set) in the prediction of progression-free survival (PFS) with the WSDL and CDL methods, respectively. PSI threshold of 1.0 could significantly differentiate the prognosis. In the test set, WSDL and CDL achieved prediction sensitivity, specificity, and accuracy of 87.50% and 62.50%, 83.33% and 83.33%, and 85.00% and 75.00%, respectively. Multivariate analysis confirmed PSI to be an independent significant predictor of PFS in both the methods.

Conclusion

The WSDL-based framework was more effective for extracting ¹⁸F-FDG PET/CT features and predicting the prognosis of ENKTL than the CDL method.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05232-3.

Comparison of Nasopharyngeal MR, 18 F-FDG PET/CT, and 18 F-FDG PET/MR for Local Detection of Natural Killer/T-Cell Lymphoma, Nasal Type

Objectives

The present study aims to compare the diagnostic efficacy of MR, ¹⁸F-FDG PET/CT, and ¹⁸F-FDG PET/MR for the local detection of early-stage extranodal natural killer/T-cell lymphoma, nasal type (ENKTL).

Patients and Methods

Thirty-six patients with histologically proven early-stage ENKTL were enrolled from a phase 2 study (Cohort A). Eight nasopharyngeal anatomical regions from each patient were imaged using ¹⁸F-FDG PET/CT and MR. A further nine patients were prospectively enrolled from a multicenter, phase 3 study; these patients underwent ¹⁸F-FDG PET/CT and PET/MR after a single ¹⁸F-FDG injection (Cohort B). Region-based sensitivity and specificity were calculated. The standardized uptake values (SUV) obtained from PET/CT and PET/MR were compared, and the relationship between the SUV and apparent diffusion coefficients (ADC) of PET/MR were analyzed.

Results

In Cohort A, of the 288 anatomic regions, 86 demonstrated lymphoma involvement. All lesions were detected by ¹⁸F-FDG PET/CT, while only 70 were detected by MR. ¹⁸F-FDG PET/CT exhibited a higher sensitivity than MR (100% vs. 81.4%, χ² = 17.641, P < 0.001) for local detection of malignancies. The specificity of ¹⁸F-FDG PET/CT and MR were 98.5 and 97.5%, respectively (χ² = 0.510, P = 0.475). The accuracy of ¹⁸F-FDG PET/CT was 99.0% and the accuracy of MR was 92.7% (χ² = 14.087, P < 0.001). In Cohort B, 72 anatomical regions were analyzed. PET/CT and PET/MR have a sensitivity of 100% and a specificity of 92.5%. The two methods were consistent (κ = 0.833, P < 0.001). There was a significant correlation between PET/MR SUVmax and PET/CT SUVmax (r = 0.711, P < 0.001), and SUVmean (r = 0.685, P < 0.001). No correlation was observed between the SUV and the ADC.

Conclusion

In early-stage ENKTL, nasopharyngeal MR showed a lower sensitivity and a similar specificity when compared with ¹⁸F-FDG PET/CT. PET/MR showed similar performance compared with PET/CT.

The predictive value of pre-treatment 18F-FDG PET/CT on treatment outcome in early-stage extranodal natural killer/T-cell lymphoma

The diagnostic value of pretreatment ¹⁸F-FDG PET/CT in early-stage extranodal natural killer/T-cell lymphoma (ENKTL) is established, but its prognostic value is still unclear. We conducted ¹⁸F-FDG PET/CT-based quantitative and qualitative analysis as well as assessed related clinical parameters in 50 patients with recently diagnosed ENKTL and treated with methotrexate, etoposide, dexamethasone, and pegaspargase (MESA)-based therapy. Patients were followed-up for 38.6 ± 17.8 months. Six patients died of tumor-related disease, and six patients presented with persistence or recurrence. The estimates of the 2-year OS and PFS for the patients were 90.0% (SE: 4.0%) and 82.0% (SE: 5.0%), respectively. Survival curves were obtained using Kaplan-Meier analysis and compared using log rank test. Based on signifiacnt results of univariate analysis, we selected Epstein-Barr virus DNA (EB-DNA), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) for multivariate analysis. Finally, MTV was found to be the significant independent predictor of both OS (p = .038) and PFS (p = .039).

PET/CT-based bone-marrow assessment shows potential in replacing routine bone-marrow biopsy in part of patients newly diagnosed with extranodal natural killer/T-cell lymphoma

PURPOSE

This study aimed to determine the potential of positron emission tomography/computed tomography (PET/CT) in replacing routine bone-marrow biopsies (BMB) in newly diagnosed extranodal natural killer/T-cell lymphoma (ENKTCL).

METHODS

Newly diagnosed patients underwent PET/CT imaging and routine BMB to assess bone/bone marrow involvement (BMI). Clinical stage and treatment plan were determined, and survival was compared.

RESULTS

In a total of 101 patients, 78 were diagnosed as stage I/II and 23 as stage III/IV without using the BMB results. No BMB-positive patients were identified in stages I/II, and therefore, the BMB results did not alter the stage and treatment choice in any patients. The sensitivity and specificity of focal skeletal PET/CT lesion(s) in assessing BMI was 100% and 92.8%, respectively, taking routine BMB as the reference standard. The overall survival (OS) and progression-free survival (PFS) of BMB-positive patients was significantly inferior (P = 0.0011 and 0.0465, respectively, in advanced-stage patients; both P < 0.0001 in all patients), and this was corroborated by the PET/CT findings (P = 0.0006 and 0.0116, respectively, in advanced-stage patients; both P < 0.0001 in all patients).

CONCLUSIONS

Based on the results, PET/CT demonstrated satisfactory predictive performance in terms of staging and prognosis in ENKTCL. BMB did not influence staging and treatment in newly diagnosed ENKTCL, and routine non-targeted BMB is not obligatory for early stage patients undergoing PET/CT. Targeted BMB is recommended to confirm BMI in advanced-stage patients.

Prognostic Value of Functional Parameters of 18F-FDG-PET Images in Patients with Primary Renal/Adrenal Lymphoma

Objectives

The aim of this study is to explore the textural features that may identify the morphological changes in the lymphoma region and predict the prognosis of patients with primary renal lymphoma (PRL) and primary adrenal lymphoma (PAL).

Methods

This retrospective study comprised nineteen non-Hodgkin's lymphoma (NHL) patients undergoing ¹⁸F-FDG-PET/CT at West China Hospital from December 2013 to May 2017. ¹⁸F-FDG-PET images were reviewed independently by two board certificated radiologists of nuclear medicine, and the texture features were extracted from LifeX packages. The prognostic value of PET FDG-uptake parameters, patients' baseline characteristics, and textural parameters were analyzed using Kaplan–Meier analysis. Cox regression analysis was used to identify the independent prognostic factors among the imaging and clinical features.

Results

The overall survival of included patients was 18.84 ± 13.40 (mean ± SD) months. Univariate Cox analyses found that the tumor stage, GLCM (gray-level co-occurrence matrix) entropy, GLZLM_GLNU (gray-level nonuniformity), and GLZLM_ZLNU (zone length nonuniformity), values were significant predictors for OS. Among them, GLRLM_RLNU ≥216.6 demonstrated association with worse OS at multivariate analysis (HR 9.016, 95% CI 1.041–78.112, p=0.046).

Conclusions

The texture analysis of ¹⁸F-FDG-PET images could potentially serve as a noninvasive strategy to predict the overall survival of patients with PRL and PAL.

Specific Soft-Tissue Invasion and LMP1 Expression Are Potential Indicators of Extranodal NK/T Cell Lymphoma, Nasal Type

BACKGROUND Extranodal NK/T cell lymphoma, nasal type (ENKTL-NT) is difficult to distinguish from nasal polyps and inverted papilloma, leading to its high misdiagnosis ratio. The aim of this study was to investigate its potential prognostic indicators. MATERIAL AND METHODS Kaplan-Meier method was used to calculate overall survival (OS) rate. Cox proportional hazards regression was used to analyze risk ratios (ORs) with 95% confidence intervals (CIs). RESULTS Nasal ala infiltration and nasal floor thickness >2.0 mm or nasal septum thickness >2.5 mm were potential prognostic factors for OS (p=0.0323 and 0.0072, respectively). Cox proportional-hazards regression indicated that high LMP1 expression and the nasal floor thickness >2.0 mm or nasal septum thickness >2.5 mm were the independent risk factors for poor OS of ENKTL-NT (HR=3.0655, p=0.028; HR=2.3650, p=0.0452, respectively). In the subgroup analysis, the OS rate was lower when the nasal floor thickness >2.0 mm or nasal septum thickness >2.5 mm in the patients who had high expression of LMP1 (p=0.0651), whereas high LMP1 expression increased the risk of worse prognostic outcome in patients with deep infiltration thickness. Thus, high LMP1 expression may contribute to the tissue invasion of ENKTL-NT. CONCLUSIONS Any patient with nasal ala soft-tissue invasion, nasal floor thickness >2.0 mm/nasal septum thickness >2.5 mm on CT imaging or high LMP1 expression should prompt immediate histopathologic diagnosis to rule out ENKTL-NT in clinical practice.

Positron emission tomography/computed tomography in the diagnosis, staging, and prognostic evaluation of natural killer/T-cell lymphoma

Natural killer/T-cell lymphoma (NKTL) is a rare subtype of non-Hodgkin's lymphoma that is associated with Epstein-Barr virus infection. The clinicopathological features of NKTL are unique among lymphomas. NKTL is an aggressive disease with a poor prognosis in the absence of effective treatment. Accurate diagnosis and staging are essential to ensure an appropriate treatment strategy and accurate prognosis of NKTL. ¹⁸F-Fluorodexoyglucose-positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) is a valuable technique in the diagnosis, staging, and prognostic evaluation of various types of malignant tumors, including NKTL. PET/CT imaging studies of patients with NKTL have shown that NKTL is ¹⁸F-FDG-avid and that PET/CT is superior to conventional methods in detecting cutaneous and extracutaneous lesions. We herein review recent PET/CT studies that have provided considerable insight into the diagnosis, staging, prognostic evaluation, and treatment effectiveness in patients with NKTL.

Prognostic significance of standardized uptake value on F18-FDG PET/CT in patients with extranodal nasal type NK/T cell lymphoma: A multicenter, retrospective analysis

OBJECTIVES

The purpose of this study was to evaluate the value of parameters assessed with F18-flurodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in predicting relapse free survival and overall survival in patients with extranodal nasal type NK/T cell lymphoma.

METHODS

Thirty-six patients with extranodal nasal type NK/T cell lymphoma, and who underwent PET/CT prior to curative treatment, were enrolled at five institutions. Volumes of interest covering the entire tumor volume were delineated on PET/CT images, and the maximum standardized uptake value (SUVmax), mean SUV (SUVmean), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were measured using thresholds of 40% of SUVmax. Furthermore, we compared the difference in F18-FDG avidity according to Epstein-Barr virus (EBV) infection status.

RESULTS

The SUVmax (p=0.041) and SUVmean (p=0.049) in patients who died were higher than the respective values of those who survived. A higher TLG (>45.8) was associated with relapse free survival (HR 7.856, p=0.034). Ann Arbor stage (III-IV, HR 14.12, p=0.004), and a higher SUVmax (>12.6, p=0.024) and SUVmean (>6.4, p=0.024) were associated with poor survival. However, neither the MTV nor the TLG (volumetric parameters) were significant predictors of death. The PET parameters SUVmax (p=0.181), SUVmean (p=0.237), MTV (p=0.636), and TLG (p=0.469) did not differ significantly between patients with and without EBV infections.

CONCLUSIONS

High TLG was the only significant predictive factor on relapse free survival. The SUVmax and SUVmean measured by F18-FDG PET/CT could be significant prognostic factors in patients with extranodal nasal type NK/T cell lymphoma.

Report on the development and application of PET/CT in mainland China

PURPOSE

To examine the development and application of systems combining positron emission and x-ray-computed tomography systems (PET/CTs) in mainland China.

METHODS

Using a questionnaire, we surveyed Chinese medical institutions on a variety topics relating to their PET/CT systems and its use. The respondents had PET/CTs installed and in clinical use before 31 December 2015. We examined the clinical scenarios to which Chinese PET/CTs were applied by reviewing the related Chinese and international literature from the start of 1995 to the end of 2013; these papers were found by searching the Wanfang and PubMed databases, respectively. The data were then classified and analyzed statistically.

RESULTS

At the end of 2015, there were 240 PET/CTs and 101 medical cyclotrons in mainland China. The total number of PET studies performed in 2015 was 469,364. The main clinical applications of PET were found to be diagnostic fludeoxyglucose (¹⁸F-FDG) imaging and oncological imaging. A minority of PET/CT studies were performed using ¹¹C-choline and other imaging agents. The number of papers relating to clinical use of PET/CT in mainland China increased each year over the period of study, in both the Chinese and international literature. Despite this progress, important problems were also apparent, including unbalanced regional development and the limited quality of the research.

CONCLUSIONS

This study provides detailed information for understanding the development PET/CT technology in mainland China, along with its geographical distribution and clinical application. It may thus prove a useful reference for all those involved in planning the future of PET/CT in China.

Accuracy of 18-F FDG PET/CT to detect bone marrow clearance in patients with peripheral T-cell lymphoma - tissue remains the issue

Staging of peripheral T-cell non-Hodgkin lymphoma (PTCL) is determined by 18-F FDG PET scan and bone marrow biopsy. This study addressed the accuracy of PET at detecting bone marrow (BM) involvement at restaging in patients with known involvement pretreatment. We identified patients with biopsy proven BM PTCL at diagnosis and concomitant BM and PET at the end of therapy. Pre-treatment PET demonstrated 50% (8/16) had a false-negative PET scan of the BM. After induction, repeat biopsy revealed 62.5% (10/16) with BM involvement. Of these 10, two had a positive PET; eight were false negative by PET. Of the six patients with a negative posttherapy BM biopsy, four were PET negative and two false positive. The sensitivity of PET at end of treatment was 20% (2/10) with a specificity of 66.7% (4/6). PET/CT is not an accurate predictor of BM involvement in patients with known PTCL in the marrow.

T-Cell Non-Hodgkin Lymphomas: Spectrum of Disease and the Role of Imaging in the Management of Common Subtypes

T-cell non-Hodgkin lymphomas (NHLs) are biologically diverse, uncommon malignancies characterized by a spectrum of imaging findings according to subtype. The purpose of this review is to describe the common subtypes of T-cell NHL, highlight important differences between cutaneous, various peripheral and precursor subtypes, and summarize imaging features and the role of imaging in the management of this diverse set of diseases.

Diagnostic value of 18F-FDG PET/CT for cutaneous extranodal natural killer/T-cell lymphoma, nasal type

OBJECTIVE

To evaluate the use of fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) in the diagnosis of cutaneous extranodal natural killer/T-cell lymphoma, nasal type (C-ENK/T-NT).

METHODS

A total of 39 patients with newly diagnosed C-ENK/T-NT were enrolled between May 2006 and November 2013. Anatomic regions (n=429; five cutaneous and six extracutaneous regions per patient) were assessed using an F-FDG PET/CT scan and conventional staging methods (CSMs). F-FDG PET/CT and CSMs were compared and evaluated for their ability to detect tumor lesions and their influence on the staging and treatment strategies. Biopsy and clinical follow-up were used as the gold standard for diagnosis.

RESULTS

In total, 139 lesions were detected by CSMs and F-FDG PET/CT, of which there were 50 cutaneous and 89 extracutaneous-positive regions. F-FDG PET/CT detected 48 cutaneous and 88 extracutaneous regions. CSMs, however, detected only 34 cutaneous lesions and 61 extracutaneous lesions that were positive for malignancy (cutaneous comparison of PET/CT vs. CSMs, P<0.001; extracutaneous comparison of PET/CT vs. CSMs, P<0.05). Using F-FDG PET/CT, 8 (42%) patients were in stage I-II and 31 patients (58%) were in stage III-IV. F-FDG PET/CT staging was consistent with the final stage determination in 94.9% (37/39) of patients, whereas CSMs staging was correct in final stage determination in 74.4% (29/39) of patients (P=0.025).

CONCLUSION

Our study showed that F-FDG PET/CT scanning is a valuable modality for the detection of cutaneous and extracutaneous lesions of C-ENK/T-NT. F-FDG PET/CT may therefore influence future staging and treatment strategies.

The usefulness of (18)F-FDG PET/CT for assessing methotrexate-associated lymphoproliferative disorder (MTX-LPD)

Background

Methotrexate-associated lymphoproliferative disorder (MTX-LPD) is a benign lymphoid proliferation or malignant lymphoma in patients who have been treated with MTX. MTX withdrawal and observation for a short period should be considered in the initial management of patients who develop LPD while on MTX therapy. Here we evaluated the diagnostic accuracy and predictive value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for MTX-LPD.

Methods

We retrospectively investigated the cases of 15 patients clinically suspected of having MTX-LPD. A total of 324 anatomic regions (207 nodal and 117 extranodal regions) were assessed by ¹⁸F-FDG PET/CT and by multi-detector row CT (MDCT). Each anatomic region was classified as either malignant or benign. The uptake of ¹⁸F-FDG was assessed semi-quantitatively with the standardized uptake value maximum (SUVmax), the whole-body metabolic tumor volume (WBMTV), and the whole-body total lesion glycolysis (WBTLG) in order to investigate predictive factors of spontaneous regression after the withdrawal of MTX.

Results

MTX-LPD lesions were observed in 92/324 (28.4 %) regions. ¹⁸F-FDG PET/CT showed 90.2 % sensitivity, 97.4 % specificity, and 95.4 % accuracy, values which were significantly higher than those of MDCT (59.8, 94.8, and 84.9 %, respectively. p < 0.002). After the withdrawal of MTX, 9/15 patients (60.0 %) achieved complete response (CR). The SUVmax, WBMTV and WBTLG values of the CR patients were 9.2 (range 2.8–47.1), 44.3 (range 0–362.6) ml, 181.8 (range 0–2180.9) ml, respectively, which were not significantly different from those of the non-CR patients: 10.6 (range 0–24.9), 15.7 (range 0–250.1) ml, and 97.4 (range 0–1052.1) ml.

Conclusions

Although ¹⁸F-FDG PET/CT was a useful tool to detect MTX-LPD lesions, none of the ¹⁸F-FDG PET parameters before the withdrawal of MTX could be used to predict CR after the withdrawal of MTX.

18F-FDG uptake for prediction EGFR mutation status in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) are a response to EGFR-tyrosine kinase inhibitor. However, a lack of sufficient tumor tissue has been a limitation for determining EGFR mutation status in clinical practice. The objective of this study was to predict EGFR mutation status in NSCLC patients based on a model including maximum standardized uptake value (SUVmax) and clinical features.We retrospectively reviewed NSCLC patients undergoing EGFR mutation testing and pretreatment positron emission tomography/computed tomography between March 2009 and December 2013. The relationships of EGFR mutations with both SUVmax and patient characteristics were evaluated, and a multivariate logistic regression analysis was performed. The model was assessed by area under the receiver-operating characteristic curve (AUC) and was prospectively validated during January to June 2014.Three hundred and sixteen patients meeting the criteria were enrolled for model construction. The SUVmax values were significantly lower for EGFR mutations (mean, 9.5 ± 5.74) than for EGFR wild-type (mean, 12.7 ± 6.43; P < 0.001). ROC curve analysis showed that the SUVmax cutoff point was 8.1, for which the AUC was 0.65 (95% confidence interval [CI], 0.60-0.72). In addition, multivariate analysis also showed that low SUVmax (≤8.1) was a predictor of EGFR mutations, for which the AUC was 0.77, combining nonsmoking history and primary tumor size (≤5 cm). Eighty-five patients were enrolled to validate the predictive model, and the overall accuracy, sensitivity, and specificity were 77.6%, 64.6% (95% CI 40.7-82.8), and 82.5% (95% CI 70.9-91.0), respectively.The specific FDG uptake value could be considered to effectively predict EGFR mutation status of NSCLC patients by considering smoking history and primary tumor size when genetic tests are not available.

Utility of ¹⁸fluoro-deoxyglucose positron emission tomography for prognosis and response assessments in a phase 2 study of romidepsin in patients with relapsed or refractory peripheral T-cell lymphoma

BACKGROUND

For patients with peripheral T-cell lymphoma (PTCL), the value of (18)fluoro-deoxyglucose positron emission tomography (FDG-PET) scans for assessing prognosis and response to treatment remains unclear. The utility of FDG-PET, in addition to conventional radiology, was examined as a planned exploratory end point in the pivotal phase 2 trial of romidepsin for the treatment of relapsed/refractory PTCL.

PATIENTS AND METHODS

Patients received romidepsin at a dose of 14 mg/m(2) on days 1, 8, and 15 of 28-day cycles. The primary end point was the rate of confirmed/unconfirmed complete response (CR/CRu) as assessed by International Workshop Criteria (IWC) using conventional radiology. For the exploratory PET end point, patients with at least baseline FDG-PET scans were assessed by IWC + PET criteria.

RESULTS

Of 130 patients, 110 had baseline FDG-PET scans, and 105 were PET positive at baseline. The use of IWC + PET criteria increased the objective response rate to 30% compared with 26% by conventional radiology. Durations of response were well differentiated by both conventional radiology response criteria [CR/CRu versus partial response (PR), P = 0.0001] and PET status (negative versus positive, P < 0.0001). Patients who achieved CR/CRu had prolonged progression-free survival (PFS, median 25.9 months) compared with other response groups (P = 0.0007). Patients who achieved PR or stable disease (SD) had similar PFS (median 7.2 and 6.3 months, respectively, P = 0.6427). When grouping PR and SD patients by PET status, patients with PET-negative versus PET-positive disease had a median PFS of 18.2 versus 7.1 months (P = 0.0923).

CONCLUSIONS

Routine use of FDG-PET does not obviate conventional staging, but may aid in determining prognosis and refine response assessments for patients with PTCL, particularly for those who do not achieve CR/CRu by conventional staging. The optimal way to incorporate FDG-PET scans for patients with PTCL remains to be determined.

TRIAL REGISTRATION

NCT00426764.

Diffuse Large B-Cell Lymphoma Infiltrating Limb Bones With a Few Lymphadenopathy Revealed on Whole-Body 18F-FDG PET/CT

A 74-year-old man presented to our hospital for a 2-month history of worsening feet and left hand swelling pain. Computed tomography reconstruction image and sagittal images of the left foot demonstrated multiple and irregular bone destruction. Orthopedic surgeon suspected tuberculosis or primary skeletal malignancy. ¹⁸F-FDG PET/CT revealed bone destruction and abnormal activity mainly in bones of both upper and lower extremities and a few lymphadenopathy at the region of left axilla and groin. Diagnosis of diffuse large B-cell lymphoma was eventually made. Subsequently, the patient was transferred to the department of oncology and responded well to antilymphoma therapy.

PRIMARY ADRENAL LYMPHOMA: A SINGLE-CENTER EXPERIENCE

OBJECTIVE

To describe the clinical presentation, biochemistry, imaging features, and treatment outcome of patients with primary adrenal lymphoma (PAL) presenting to a single tertiary care center.

METHODS

We performed a retrospective analysis of case records of 7 patients diagnosed with PAL between January 2011 and May 2014 at our institution in Mumbai, India.

RESULTS

Median age of presentation in our series was 48 years (range, 41 to 60 years), with a male to female ratio of 6:1. Bilateral adrenal involvement was seen in 4 of 7 patients (58%). Adrenal insufficiency (AI) was seen in 3 of the 4 patients with bilateral involvement (75%). Computed tomography showed slight to moderate contrast enhancement of adrenal masses in 4 of 5 patients (80%). Diffuse, large, B-cell lymphoma (DLBCL) was the most common immunophenotype (85%). One patient died due to rapid disease progression even before starting chemotherapy. Six patients were treated with chemotherapy and/or external beam radiotherapy. After 1 year, 2 more patients had died, whereas 4 patients were in remission.

CONCLUSION

PAL should always be considered in differential diagnosis of bilateral adrenal mass with AI. DLBCL is the most common histologic subtype of PAL. Despite treatment, long-term prognosis of PAL remains poor.

Utility of PET/CT in the diagnosis and staging of extranodal natural killer/T-cell lymphoma: a systematic review and meta-analysis

The role of 18F-fuorodexoyglucose-positron emission tomography/computed tomography (18F-FDG-PET/CT) in the staging of Hodgkin lymphoma (HL) and aggressive B-cell non-Hodgkin lymphomas (NHL) has been demonstrated extensively. Nevertheless, the role of PET/CT in the diagnosis, staging, prognosis, and treatment evaluation of natural killer (NK)/T-cell lymphoma remains indeterminate. To systematically review and meta-analyze the publications on the value of 18F-FDG-PET/CT in the diagnosis and staging of NK/T-cell lymphoma. Pubmed, Embase, Cochrane Library, and some other database were searched for initial studies (last updated on May 8th, 2014).The eligibility criteria were studies assessing the usefulness of PET/CT in the staging of NK/T-cell lymphoma, patients were diagnosed as NK/T-cell lymphoma through pathology, or clinical and imaging follow-up. Sensitivities and specificities of 18F-FDG-PET/CT in individual studies were assessed. The summary receiver operating characteristic curve (sROC) and the area under the curve (AUC) were calculated. The "Meta-Disc 1.4" software was used for data analysis. Eight studies, with a total of 135 NK/T-cell lymphoma patients, were included in this meta-analysis. In terms of the 6 studies with patient based data, the pooled sensitivity and specificity of PET/CT in the diagnosis of NK/T-cell lymphoma were 0.95 (95% CI: 0.89-0.98) and 0.40 (95% CI: 0.09-0.78), respectively. For lesion-based analysis, with 1546 lesions included, the pooled sensitivity and specificity of PET/CT in the staging of NK/T-cell lymphoma were 0.98 (95% CI: 0.96-0.99) and 0.99 (95% CI: 0.99-1.00), respectively. For the patient based data, the AUC and Q index were 0.8537 and 0.7847, respectively. For lesion based data, the AUC and Q index were 0.9959 and 0.9755, respectively. The results of this current meta-analysis indicated that PET/CT could be used as a valuable diagnostic and staging tool for NK/T-cell lymphoma.

Midtreatment ¹⁸F-FDG PET/CT Scan for Early Response Assessment of SMILE Therapy in Natural Killer/T-Cell Lymphoma: A Prospective Study from a Single Center

In a prospective study of newly diagnosed or relapsed histologically proven extranodal natural killer/T-cell lymphoma (ENKTL) patients, we aimed to determine the accuracy of midtreatment (18)F-FDG PET for response assessment using both visual and quantitative analyses.

METHODS

Twenty-four patients (12 men, 12 women; median age, 50 y; age range, 16-83 y) were referred for pre-, mid- (after 2-3 cycles of SMILE [prednisolone, methotrexate, ifosfamide, L-asparaginase, etoposide] chemotherapy), and end-treatment PET/CT scans (n = 24, 24, and 17, respectively) using a standardized protocol. Sixty-five PET/CT scans were analyzed visually using the Deauville 5-point score (DS), and the lesion with the highest maximum standardized uptake value (SUV(max)) was recorded. Survival curves were obtained using Kaplan-Meier analysis and compared using the log rank test, followed by multivariate analysis using the Cox proportional hazards model to assess the independent effects of International Prognostic Index (IPI) score (0-1 vs. 2-5), stage (stage I/II vs. stage III/IV), sex, DS (1-3 vs. 4-5), SUV(max), and change in SUV(max) on overall survival (OS) and progression-free survival (PFS). The mean (±SD) follow-up period was 32 mo (±21 mo).

RESULTS

For 2-y OS, the following parameters were predictive: IPI score (P = 0.047), DS at mid- and end-treatment (P < 0.001), and SUV(max) at mid- and end-treatment (P < 0.001 and 0.045, respectively). For 2-y PFS, the following parameters were predictive: sex (P = 0.006), stage (P = 0.034), IPI score (P = 0.038), DS at mid- and end-treatment (P < 0.001 and 0.001, respectively), and SUV(max) at midtreatment (P = 0.001). Multivariate analysis showed DS on mid- and end-treatment scans to be the only significant independent predictor of both OS (P = 0.004 and 0.018, respectively) and PFS (P = 0.004 and 0.014, respectively). The 2-y estimate for OS and PFS was 81% and 62%, respectively, in patients with a DS of 1-3, compared with 17% in patients with a DS of 4-5 (P < 0.001 and 0.001, respectively). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the midtreatment DS for prediction of OS and PFS were 63%, 94%, 83%, 83%, and 83%, respectively.

CONCLUSION

Midtreatment PET/CT is a valuable tool for early treatment response assessment in extranodal natural killer/T-cell lymphoma patients.

Extranodal lymphomas of head and neck with emphasis on NK/T-cell lymphoma, nasal type

PURPOSE

To determine the occurrence, clinical course and outcome of our patients with natural killer/T-cell lymphoma (NKTCL), nasal type. The nasal type of natural killer/T-cell lymphoma (NKTCL), is rare in the European population but is more frequent in Asia, Central and South America where it accounts for 15-20% of all non-Hodgkin lymphomas (NHL). This type of lymphoma is characterized by tissue necrosis and destruction of the nasal cavity and upper aero-digestive tract. The disease is closely associated with Epstein-Barr virus (EBV) infection and has an aggressive clinical course, poor clinical outcome and high resistance to chemotherapy.

PATIENTS

63 patients with NHL were treated in our department between 2006 and 2011. Eleven patients were diagnosed with extranodal lymphoma, 6 in the area of head and neck. Three of them belonged to NKTCL, nasal type group (4.7%), 1 was diffuse large B cell lymphoma and 2 were marginal zone lymphomas.

CONCLUSION

Two out of 3 patients with nasal type NKTCL, had extremely aggressive disease resistant to applied chemotherapy (anthracycline containing regimen), while 1 patient remains in complete remission 6 years after diagnosis.

18F-fluorodeoxyglucose positron emission tomography in the staging and prognosis of T cell lymphoma

We previously reported that (18)F-fluorodeoxyglucose positron emission tomography scan (FDG-PET) is almost universally positive in patients with T cell lymphoma. In the present analysis we examined the impact of FDG-PET on the initial staging of peripheral T cell lymphomas (PTCLs), and the prognostic value of interim FDG-PET. This retrospective analysis identified patients with mature T or natural killer (NK) lymphomas who had PET scans as part of initial staging or staging at relapse [(n = 95) (staging cohort)] in the PTCL database at Memorial Sloan-Kettering Cancer Center. A subset of these patients had repeat PET for interim restaging during initial therapy with curative intent [(n = 50) (interim restaging cohort)]. The frequency of specific T cell histologies included in this analysis were: PTCL not otherwise specified (NOS) (n = 35); angioimmunoblastic T cell lymphoma (AITL) (n = 17); anaplastic large cell lymphoma (ALCL), ALK-1+ (n = 11) and ALK-1- (n = 12); adult T cell lymphoma/leukemia (ATLL) (n = 7); NK/T cell lymphoma (NKTCL) (n = 10); and enteropathy-associated T cell lymphoma (EATL) (n = 3). In the staging cohort, 77 patients were newly diagnosed, and 18 had relapsed disease. Pretreatment FDG-PET was positive in 96% of patients. PET identified additional disease sites in 47/95 patients (50%) when added to conventional staging. Most frequently identified additional sites were: other nodal (n = 24); bone (n = 10); skin (n = 8); nasopharynx (n = 4); spleen (n = 3); and lung (n = 2). However, FDG-PET modified computed tomography (CT)-based staging in only 5/95 patients (5.2%): two patients were upstaged and three patients were downstaged. FDG-PET-based staging did not alter planned treatment for any patient. Interim restaging with PET was performed after a median of 4 cycles of chemotherapy. In this cohort, treatment regimens included cyclophosphamide, doxorubicin, vincristine and prednisone CHOP (n = 19); CHOP/ifosfamide, carboplatin and etoposide (ICE) (n = 26); and other (n = 7). Subsequently, 29 patients were consolidated with either autologous (n = 22) or allogeneic (n = 7) stem cell transplant. After a median follow-up of 3.4 years for surviving patients, those with negative interim PET had superior progression-free survival (PFS) compared to patients with positive interim PET (p = 0.03). There were no differences in overall survival (OS). In PTCL, FDG-PET commonly identifies additional sites of disease but infrequently impacts CT-based staging and does not influence therapy. Interim FDG-PET may predict for PFS. FDG-PET should be integrated into prospective trials to confirm these findings.

Clinical value of metabolic tumor volume by PET/CT in extranodal natural killer/T cell lymphoma

This study investigated whether metabolic tumor volume (MTV) by PET/CT as indicator of extent of lymphoma burden would be a prognostic factor in stage I(E)/II(E) extranodal natural killer/T cell lymphoma (ENKTCL). Eighty patients with stage I(E)/II(E) ENKTCL in the upper aerodigestive tract underwent PET/CT at diagnosis were enrolled and 32 patients received upfront radiotherapy (RTx). MTV was measured on PET/CT images by the extranodal region above SUV, 2.5. Receiver operating curve analyses indicated that an MTV of 35.2 cm(3) was the ideal cut-off to distinguish between low and high MTV groups. Clinical outcomes were compared according to several prognostic factors (age, stage, high performance status [PS], high International Prognostic Index, elevated lactate dehydrogenase [LDH], local tumor invasiveness [LTI], high MTV and up-front RT). High PS, elevated LDH, LTI, high MTV and upfront RT were associated with survivals. In multivariate analysis, high MTV (PFS, HR=4.170, 95% CI=1.714-10.147, p=0.002; OS, HR=4.102, 95% CI=1.617-10.408, p=0.003) and up-front RT (PFS, HR=0.410, 95%CI=0.178-0.946, p=0.037; OS, HR=0.365, 95% CI=0.152-0.872, p=0.023) were significant independent prognostic factors. Upfront RTx and extent of tumor burden, as measured by the MTV, had significant prognostic value in patients with ENKTCL.

Preliminary study on the evaluation of olfactory neuroblastoma using PET/CT

PURPOSE

Because of paucity of data available regarding the utility of PET/CT in the diagnosis and staging of patients with olfactory neuroblastoma (ONB), we retrospectively analyzed the efficacy of PET/CT in 9 patients with ONB.

MATERIALS AND METHODS

Whole-body F-18 FDG PET/CT was performed in 7 patients with newly diagnosed ONB, as well as in 1 patient with recurrence and in 1 patient with remnant tumor. Regional C-11 choline (C-11 CHO) PET/CT was performed in 2 patients with negative F-18 FDG scans. The lesion with intense radiotracer uptake was suggested as positive for tumor and the results of PET/CT were compared with conventional staging examinations.

RESULTS

F-18 FDG PET/CT was positive in 7/9 (77.7%) patients with ONB. In 2 patients with negative F-18 FDG, the lesions were C-11CHO avid. Both the primary tumors and its invasions were clearly delineated by F-18 FDG or C-11 CHO PET/CT. SUVmax of F-18 FDG in the primary tumor was 6.37 ± 4.22 and did not correlate with lesion size (F-18 FDG/size: r = 0.097, P = 0.820). Whole-body F-18 FDG PET/CT detected parapharyngeal and cervical lymph node metastases in 2 patients, lung metastases in 1 patient, liver metastases in 1 patients, and bone metastases in 2 patients. PET/CT altered the stages of 3 of 9 patients with upstaging in 2 patients and downstaging in 1 patient.

CONCLUSIONS

PET/CT may be useful for the diagnosis and staging of ONB.

PET/CT aids the staging of and radiotherapy planning for early-stage extranodal natural killer/T-cell lymphoma, nasal type: a case series

Extranodal natural killer/T-cell lymphoma (ENKTL), nasal type, is a rare form of non-Hodgkin lymphoma. Treatment of ENKTL primarily relies on radiation; thus, proper delineation of target volumes is critical. Currently, the ideal modalities for delineation of gross tumor volume for ENKTL are unknown. We describe three consecutive cases of localized ENKTL that presented to the Nova Scotia Cancer Centre in Halifax, Nova Scotia. All patients had a planning CT and MRI as well as a planning FDG-PET/CT in the radiotherapy treatment position, wearing immobilization masks. All patients received radiation alone. In two patients, PET/CT changed not only the stage, but also the target volume requiring treatment. The third patient was unable to tolerate an MRI, but was able to undergo PET/CT, which improved the accuracy of the target volume. PET/CT aided the staging of and radiotherapy planning for our patients and appears to be a promising tool in the treatment of ENKTL.

F-18 FDG PET for evaluation of bone marrow involvement in non-Hodgkin lymphoma: a meta-analysis

BACKGROUND

In recent years, the use of F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) has become widespread for the staging of lymphoma. In non-Hodgkin lymphoma (NHL), the bone marrow (BM) involvement is a sign of extensive disease, and the iliac crest BM biopsy (BMB) is the established method for the detection of BM infiltration. However, iliac crest BMB is associated with a high rate of false-negative results. We assess the ability of FDG PET or PET/CT scan to ascertain the presence of BM involvement in aggressive and indolent NHL.

METHODS

The authors conducted a systematic MEDLINE search of articles published (last update, May 2010). Two reviewers independently assessed the methodological quality of each study. A meta-analysis of the reported sensitivity and specificity of each study was performed.

RESULTS

Eight studies met the inclusion criteria. The studies had several design deficiencies. Pooled sensitivity and specificity for the detection of non-Hodgkin aggressive lymphoma were 0.74 (95% CI, 0.65-0.83) and 0.84 (95% CI, 0.80-0.89), respectively. Pooled sensitivity and specificity for the detection of non-Hodgkin indolent lymphoma were 0.46 (95% CI, 0.33-0.59) and 0.93 (95% CI, 0.88-0.98), respectively.

CONCLUSIONS

The diagnostic accuracy of FDG PET or PET/CT scans was slightly higher but without significant statistical difference (P = 0.1507) in patients with non-Hodgkin aggressive lymphoma as compared with those with non-Hodgkin indolent lymphoma. The sensitivity to detect indolent lymphoma BM infiltration was low for FDG PET or PET/CT.

18F-fluorodeoxyglucose-positron emission tomography before, during and after treatment in mature T/NK lymphomas: a study from the GOELAMS group

BACKGROUND

In non-cutaneous T-cell/natural killer (T/NK) lymphomas, the prognostic value of (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) during or after therapy is unknown.

PATIENTS AND METHODS

In this retrospective study, 54 T/NK lymphoma patients were assessed using FDG-PET before (n = 40), during (n = 44) and/or after therapy (n = 31).

RESULTS

FDG-PET showed an abnormal FDG uptake in all cases. Interim FDG-PET was negative in 25 of 44 cases. After completion of therapy, 19 of 31 patients reached complete remission with negative FDG-PET. In ALK+ anaplastic large cell lymphomas, the 4-year progression-free survival (PFS) was 80% and the negative predictive value of post-therapy FDG-PET was 83% (n = 9). In ALK- T/NK lymphomas, the 4-year PFS was 59% for patients with a negative interim FDG-PET versus 46% for patients with a positive interim FDG-PET (P = 0.28, n = 35). Similarly, there was no statistical difference in 4-year PFS between negative and positive post-therapy FDG-PET in these lymphomas (51% and 67%, respectively, P = 0.96). The 4-year cumulative incidence of relapse from a negative post-therapy FDG-PET was 53% in ALK- T/NK lymphomas.

CONCLUSIONS

Although T/NK lymphomas are FDG-avid at diagnosis, a negative interim or post-therapy FDG-PET does not translate into an improved PFS in ALK- T/NK lymphomas.