FDG-PET in T-cell and NK-cell neoplasms.

BACKGROUND: A growing number of studies demonstrate the utility of (18)fluoro-2-deoxyglucose positron emission tomography (FDG-PET) in the management of malignant lymphoma. The results of FDG-PET, however, have not been studied extensively for T-cell and natural killer (NK)-cell neoplasms. PATIENTS AND METHODS: We retrospectively evaluated pretreatment FDG-PET scans in 41 patients with T/NK-cell neoplasms diagnosed according to the World Health Organization (WHO) classification. Histological subtypes frequently included were peripheral T-cell lymphoma, unspecified (PTCLu, n = 11), extranodal NK/T-cell lymphoma, nasal type (ENKL, n = 8), primary cutaneous anaplastic large cell lymphoma (C-ALCL, n = 5), and angioimmunoblastic T-cell lymphoma (AILT, n = 4). RESULTS: FDG-PET detected a lymphoma lesion in at least one site in 36 out of 41 patients. The positive rate was equally high in most histological subtypes except for cutaneous lymphomas: PTCLu 91%, ENKL 100%, C-ALCL 60%, AILT 100%. All the patients without an FDG-avid lesion had lesions restricted to skin. Among patients who had cutaneous lesions, only 50% had FDG-avid cutaneous lesions, all of which were tumorous. The positive rate of FDG-PET for bone marrow involvement was only 20%. CONCLUSION: T/NK-cell neoplasms incorporated in this study were generally FDG-avid except for cutaneous lesions and bone marrow involvement.     

Role of fluorine-18 fluoro-deoxyglucose positron emission tomography scan in the evaluation and follow-up of patients with low-grade lymphomas

BACKGROUND: Fluorine-18 fluoro-deoxyglucose positron emission tomography (FDG-PET) scanning has excellent sensitivity and specificity for staging non-Hodgkin lymphomas, but to the authors' knowledge few studies to date have evaluated FDG-PET in low-grade lymphomas only. METHODS: A retrospective study was performed on patients with biopsy-proven nontransformed and transformed follicular lymphoma (FL), B-cell small-cell lymphocytic lymphoma (SLL/CLL), or marginal zone lymphoma (MZL) who underwent PET and computed tomography (CT) scans within 3 weeks. Standard uptake values (SUV) of all abnormal foci were measured. RESULTS: In FL, PET demonstrated 94% sensitivity and 100% specificity for staging. PET was more specific than CT for detecting recurrence or assessing therapeutic responses (91% vs. 50%). FDG avidity among patients with WHO Grades 1, 2, and 3 disease was not significantly different (analysis of variance [ANOVA]). For MZL staging, PET had moderate sensitivity (71%) and outperformed CT alone in the depiction of extranodal sites (85% vs. 57% sensitivity). In SLL/CLL, PET sensitivity was 53% and underestimated disease extent in 5 of 19 patients (26%) compared with CT. PET did not affect initial management but confirmed suspected recurrences in 75% of patients. Nontransformed FL had a higher SUV (ANOVA, P < .05) compared with MZL and SLL/CLL. SUV was higher in transformed than in nontransformed tumors (P < .001, Student t test). CONCLUSIONS: PET usefulness in staging low-grade lymphomas varies depending on histology. PET sensitivity is excellent in FL and moderate in MZL. PET is more specific than CT for follow-up in all types. PET has limited usefulness for SLL/CLL staging. However, a suggestive pattern of hazy and mild uptake was often noted in positive scans. In all low-grade lymphomas, the emergence of foci of intense uptake should raise suspicion of conversion to high-grade disease.     

2-[18F]fluoro-2-deoxyglucose positron-emission tomography in staging, response evaluation, and treatment planning of lymphomas

2-[18F]fluoro-2-deoxyglucose positron-emission tomography (FDG-PET) is used increasingly in the clinical management of lymphomas. With regard to staging, FDG-PET is more sensitive and specific than conventional staging methods in FDG avid lymphomas (ie, Hodgkin lymphoma and most aggressive non-Hodgkin lymphomas). Despite methodological problems, in particular the lack of a valid reference test, FDG-PET is approved and generally used for this purpose. With regard to response evaluation, FDG-PET at the end of treatment seems to aid considerably in differentiating between residual masses with or without residual lymphoma. Hence, new revised response criteria have been proposed, incorporating the result of FDG-PET at the end of treatment. An early interim FDG-PET scan after 1 to 3 cycles of chemotherapy is a very strong predictor of outcome, and trials are now in progress testing treatment modifications on this basis. With regard to treatment planning, in the context of combined-modality therapy, radiotherapy for lymphomas is moving toward more conformal techniques reducing the irradiated volume to include only the macroscopic lymphoma. In this situation, accurate imaging is essential, and FDG-PET coregistered with the planning computed tomography (CT) scan is used increasingly. The availability of PET/CT scanners suited for virtual simulation has aided this process. However, clinical data evaluating this technique are at present sparse.     

Treatment algorithms for mature T-cell and natural killer-cell neoplasms

Mature T-cell and natural killer (NK)-cell lymphomas are rare neoplasms, differing geographically in frequencies. T-cell lymphomas are more common in Asia than in western countries, and NK-cell lymphomas occur almost exclusively in Asia and South America. The rarity of these lymphomas means that treatment algorithms of T-cell and NK-cell lymphomas have not been well established. Angioimmunoblastic T-cell lymphoma, anaplastic large cell lymphoma and peripheral T-cell lymphoma, not otherwise specified, are the more commonly encountered T-cell lymphomas. Treatment with anthracycline-based regimens designed for aggressive B-cell lymphomas gives unsatisfactory results. Cutaneous T-cell lymphomas may remain indolent, but outcome is poor for advanced diseases. Novel therapies, including monoclonal antibodies, nucleoside analogs, histone deacetylase inhibitors and small molecules targeting cellular signaling pathways, are being explored alone or in combination with chemotherapy. High-dose chemotherapy with hematopoietic stem cell transplantation (HSCT) is recommended for high-risk cases. NK-cell lymphomas exhibit the multidrug resistance phenotype due to P-glycoprotein expression, so that anthracycline-based regimens are ineffective. Non-multidrug resistance-dependent regimens and L-asparaginase-based protocols have been shown to be highly active. Autologous HSCT is not routinely performed. The role of allogeneic HSCT is being examined.     

Positron Emission Tomography in Lymphoma: Comparison with Computed Tomography and Gallium-67 Single Photon Emission Computed Tomography

With the advent of positron emission tomography (PET), metabolic imaging has become a reality for tumor staging and monitoring response to therapy in lymphoma. Increased Fluorine-18 fluorodeoxyglucose ([¹⁸F]FDG) uptake in lymphomas has been well documented in the literature; it is based upon elevated glycolysis and longer residence time of FDG in malignant cells compared to most normal tissues. This suggests that in tumor staging, FDG-PET may be more sensitive and specific than the anatomic imaging modalities. Computed tomography (CT) is the standard imaging modality for the staging and restaging of lymphoma, and Gallium-67 (⁶⁷Ga) scintigraphy has played an important role in monitoring response to therapy and follow-up of patients. Published results suggest that FDG-PET is superior to ⁶⁷Ga imaging and may be equal or superior to CT for the detection of nodal as well as extranodal involvement in lymphoma.     

Recent developments in the biology and therapy of T-cell and natural killer-cell lymphomas

PURPOSE OF REVIEW: T-cell/natural killer (T/NK)-cell lymphomas represent a group of poor-risk lymphoproliferative disorders that have only recently been recognized as distinct clinicopathologic entities. The average outcome with currently available therapy is substantially inferior to that of aggressive B-cell lymphomas. Significant gaps remain in our knowledge of their origin, diagnosis, and clinical spectrum. This review outlines recent developments in the biology and molecular genetics of these disorders, current diagnostic challenges, and future avenues for therapy. RECENT FINDINGS: Several cancer-prone transgenic mouse models that develop predominantly T/NK-cell lymphomas have been produced in the past 2 to 3 years. These models point to an important role for chronic cytokine stimulation and for disruption of genes involved in the control of chromatin remodeling and maintenance of genome integrity in the pathogenesis of T-cell lymphomas. The recognition of T/NK-cell lymphomas has been greatly facilitated by the broad acceptance of standard diagnostic criteria and by the increasing availability of assays for the analysis of T-cell receptor rearrangement and a more precise definition of functional T/NK-cell subsets. New drugs with potential for use in T/NK-cell lymphomas, including monoclonal antibodies, tyrosine kinase inhibitors, synthetic retinoids, immunoconjugates, and immunosuppressive molecules with novel mechanisms of action are in the early phase of clinical investigation. SUMMARY: Much remains to be learned in the pathogenesis, clinical spectrum, and optimal therapy of T/NK-cell lymphomas. The availability of animal models of disease, new diagnostic tools, and targeted drugs with novel mechanisms of action should lead to rapid progress in this group of malignancies in the near future.     

High-dose therapy and autologous stem cell transplantation in Korean patients with aggressive T/NK-cell lymphoma

The proportion of aggressive T/NK-cell lymphoma in Korea is larger than in the West, and it shows a lower response to conventional chemotherapy and poorer survival than diffuse large B-cell lymphoma. This study was undertaken to evaluate the response rate and survival and to document the prognostic factors in patients with T/NK-cell lymphoma who have undergone high-dose therapy (HDT). Eligibility for the study was a mature T/NK-cell lymphoma with initially poor risk (as high or high intermediate risk on age-adjusted International Prognostic Index) or relapsed cases. Twenty-eight patients from 6 centers were reviewed retrospectively. The M : F ratio was 20:8, and median age was 36 years (range 16--60 years). Twelve patients had unspecified peripheral T-cell lymphomas, 7 anaplastic large-cell lymphomas, 6 nasal T/NK-cell lymphomas, and 3 angioimmunoblastic T-cell lymphomas. Disease status at transplant were initially poor risk in 15, chemosensitive relapse in 8 and chemo-resistant relapse in 5 patients, respectively. A complete response (CR) after HDT comprised 20 patients, including 16 with continued CR. Absolute neutrophil count ( > 500/microl) recovered at a median 11 days after autologous stem cell transplantation in 26 patients. Two therapy-related mortalities occurred. Estimated 3-year event-free survival and overall survival (OS) (+/- SE) were 24+/- 9 and 42+/- 10 months, respectively. Only CR status after HDT influenced OS (P=0.000). Therefore, an initial approach with effective induction and HDT may result in a better outcome in T/NK-cell lymphoma.     

Value of [18F]fluorodeoxyglucose-positron emission tomography in managing patients with aggressive non-Hodgkin's lymphoma

An increased glucose metabolic rate is observed with various degrees of intensity in different subtypes of aggressive lymphomas. [(18)F]Fluorodeoxyglucose (FDG)-positron emission tomography (PET; FDG-PET) allows functional imaging of this phenomenon through 3-dimensional tomographic slices, which are now easily fused with computed tomography (CT) images. [(18)F]Fluorodeoxyglucose-PET staging appears superior to conventional staging modalities for detecting nodal and extranodal lymphoma. When performed after first-line chemotherapy, FDG-PET is more efficient than CT and conventional diagnostic methods to predict the disease outcome. Some studies have reported that the relapse rate is 100% in patients with positive PET findings after treatment and 17% in patients with negative PET findings. This imaging modality can also assess early response after 1-2 cycles of chemotherapy, thus identifying responders from patients whose cancer will fail to respond to first-line therapy or will relapse shortly after having exhibited a partial or complete remission. [(18)F]Fluorodeoxyglucose-PET also seems useful for an accurate selection of patients who will benefit from highly intensive treatment.     

Role of fluorine‐18‐fluorodeoxyglucose positron emission tomography/computed tomography in evaluating breast mucosa‐associated lymphoid tissue lymphoma: A case series

Mucosa‐associated lymphatic tissue (MALT) lymphoma of the breast is an extremely rare disease; its pathogenesis is not clear because of the rarity of disease, and the best diagnostic method has yet to be established. The metabolic behavior of this lymphoma is not still clear because only a few case reports are present in literature describing the possible role of fluorine‐18‐fluorodeoxyglucose positron emission tomography/computed tomography (18F‐FDG PET/CT) in this field. This report presents 4 cases of women with histologically proven breast MALT lymphoma who underwent 7 18F‐FDG PET/CT throughout the course of disease. All patients underwent staging PET/CT showing in all cases an FDG avid lesion corresponding to breast lymphoma; 3 patients underwent 18F‐FDG PET/CT also after chemotherapy. Our results suggest that breast MALT lymphomas are 18F‐FDG‐avid lymphomas. Positron emission tomography/computed tomography showed heterogeneous but high FDG uptake (mean maximum standardized uptake value 7.9), suggesting that it could be part of diagnostic workup and restaging process.     

Positron emission tomography/computed tomography in the management of Hodgkin and B-cell non-Hodgkin lymphoma: An update

¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) is now an integral part of lymphoma staging and management. Because of its greater accuracy compared with CT alone, PET/CT is currently routinely performed for staging and for response assessment at the end of treatment in the vast majority of FDG-avid lymphomas and is the cornerstone of response classification for these lymphomas according to the Lugano classification. Interim PET/CT, typically performed after 2 to 4 of 6 to 8 chemotherapy/chemoimmunotherapy cycles with or without radiation, is commonly performed for prognostication and potential treatment escalation or de-escalation early in the course of therapy, a concept known as response-adapted or risk-adapted treatment. Quantitative PET is an area of growing interest. Metrics, such as the standardized uptake value, changes (Δ) in the standardized uptake value, metabolic tumor volume, and total lesion glycolysis, are being investigated as more reproducible and potentially more accurate predictors of response and prognosis. Despite the progress made in standardizing the use of PET/CT in lymphoma, challenges remain, particularly with respect to its limited positive predictive value, emphasizing the need for more specific molecular probes. This review highlights the most relevant applications of PET/CT in Hodgkin and B-cell non-Hodgkin lymphoma, its strengths and limitations, as well as recent efforts at implementing PET/CT-based metrics as promising tools for precision medicine.     

Value of [18F]Fluorodeoxyglucose–Positron Emission Tomography in Managing Adults with Aggressive Non-Hodgkin's Lymphoma

An increased glucose metabolic rate is observed with various degrees of intensity in different subtypes of aggressive lymphomas. [¹⁸F]Fluorodeoxyglucose (FDG)–positron emission tomography (PET; FDG-PET) allows functional imaging of this phenomenon through 3-dimensional tomographic slices, which are now easily fused with computed tomography (CT) images. [¹⁸F]Fluorodeoxyglucose–positron emission tomography staging appears superior to conventional staging modalities for detecting nodal and extranodal lymphoma. When performed after first-line chemotherapy, FDG-PET is more efficient than CT and conventional diagnostic methods to predict the disease outcome. Some studies have reported that the relapse rate is 100% in patients with positive PET findings after treatment and 17% in patients with negative PET findings. This imaging modality can also assess early response after 1-2 cycles of chemotherapy, thus identifying responders from patients whose cancer will fail to respond to first-line therapy or will relapse shortly after having exhibited a partial or complete remission. [¹⁸F]Fluorodeoxyglucose–PET also seems useful for an accurate selection of patients who will benefit from highly intensive treatment.     

Comparison between whole-body MRI and Fluorine-18-Fluorodeoxyglucose PET or PET/CT in oncology: a systematic review

Background

The aim of the article is to systematically review published data about the comparison between positron emission tomography (PET) or PET/computed tomography (PET/CT) using Fluorine-18-Fluorodeoxyglucose (FDG) and whole-body magnetic resonance imaging (WB-MRI) in patients with different tumours.

Methods

A comprehensive literature search of studies published in PubMed/MEDLINE, Scopus and Embase databases through April 2012 and regarding the comparison between FDG-PET or PET/CT and WB-MRI in patients with various tumours was carried out.

Results

Forty-four articles comprising 2287 patients were retrieved in full-text version, included and discussed in this systematic review. Several articles evaluated mixed tumours with both diagnostic methods. Concerning the specific tumour types, more evidence exists for lymphomas, bone tumours, head and neck tumours and lung tumours, whereas there is less evidence for other tumour types.

Conclusions

Overall, based on the literature findings, WB-MRI seems to be a valid alternative method compared to PET/CT in oncology. Further larger prospective studies and in particular cost-effectiveness analysis comparing these two whole-body imaging techniques are needed to better assess the role of WB-MRI compared to FDG-PET or PET/CT in specific tumour types.     

Practical Utility of the Revised European-American Classification of Lymphoid Neoplasms for Japanese Non-Hodgkin's Lymphomas

A clinicopathological study of 515 non-Hodgkin's lymphoma (NHL) cases was performed using the revised European-American classification of lymphoid neoplasms (REAL classification) in an HTLV1-nonendemic area of Japan. The following characteristics were revealed: 1) frequency of extranodal lymphomas was high (59%) with 79% B-cell lymphomas in this series, while the overall ratio of B:T/NK lineage was 3.7:1; 2) the most common type was the diffuse large B-cell lymphoma (46%), follicle center lymphomas occurred at an incidence lower (15%) than that in European and American populations, and marginal zone B-cell lymphomas accounted for as much as 12%; 3) peripheral T-cell lymphomas were common (19%), with the unspecified type predominant (11%), while adult T-cell lymphomas were present at a level equivalent to that among European and American patients (1%). Clear segregation of survival curves was rated according to cell lineage and B-cell lymphomas had a better prognosis than T/NK-cell lymphomas. Furthermore, new subtypes in the REAL classification, such as marginal zone B-cell and mantle cell lymphomas, exhibited distinct curves. Taken altogether, the REAL classification demonstrated advantages for assessment of Japanese NHL cases.     

18F-FDG PET/CT or PET Role in MALT Lymphoma: An Open Issue not Yet Solved—A Critical Review

Mucosa-associated lymphoid tissue (MALT) lymphoma involves the mucosa-associated lymphoid tissue potentially arising from any mucosal site, with the stomach as the most common site of involvement. MALT lymphoma is not usually an aggressive disease with a good prognosis except for selected cases. Fluorine-18 (¹⁸F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is a noninvasive imaging tool used for staging, restaging, and evaluation of the treatment response in non-Hodgkin and Hodgkin lymphoma. However, its effective role in MALT lymphoma is not yet clear. The open question is whether these lymphomas are ¹⁸F-FDG avid or not, with conflicting results reported in the literature. Consequently, the possible clinical role of ¹⁸F-FDG PET/CT for staging and restaging purposes is under debate. The aim of the present review was to analyze the reported data about the role of ¹⁸F-FDG PET or PET/CT in patients with MALT lymphoma. We performed a comprehensive computer literature search of the Scopus, Cochrane, PubMed/MEDLINE, and Embase databases, including articles reported up to August 2019. We included 32 studies that had analyzed ¹⁸F-FDG PET or PET/CT for patients with MALT lymphoma. We analyzed the metabolic behavior of MALT lymphoma using ¹⁸F-FDG PET and the effect of the PET findings in the staging, treatment response evaluation, and prognosis.     

Enhanced marrow [18F]fluorodeoxyglucose uptake related to myeloid hyperplasia in Hodgkin's lymphoma can simulate lymphoma involvement in marrow

[18F]Fluorodeoxyglucose (FDG) positron emission tomography (PET) is increasingly used for the clinical staging of lymphomas and for assessment of response to therapy. We report the case of a woman with classic Hodgkin's lymphoma who had marked FDG uptake by tumor and bone marrow suggestive of diffuse marrow involvement by lymphoma. However, iliac crest bone marrow examination showed marked myeloid hyperplasia without evidence of lymphoma involvement. We discuss the implications for interpretation of FDG-PET imaging of bone marrow in lymphomas.     

Practical utility of the revised European-American classification of lymphoid neoplasms for Japanese non-Hodgkin's lymphomas.

A clinicopathological study of 515 non-Hodgkin's lymphoma (NHL) cases was performed using the revised European-American classification of lymphoid neoplasms (REAL classification) in an HTLV1-nonendemic area of Japan. The following characteristics were revealed: 1) frequency of extranodal lymphomas was high (59%) with 79% B-cell lymphomas in this series, while the overall ratio of B:T/NK lineage was 3.7:1; 2) the most common type was the diffuse large B-cell lymphoma (46%), follicle center lymphomas occurred at an incidence lower (15%) than that in European and American populations, and marginal zone B-cell lymphomas accounted for as much as 12%; 3) peripheral T-cell lymphomas were common (19%), with the unspecified type predominant (11%), while adult T-cell lymphomas were present at a level equivalent to that among European and American patients (1%). Clear segregation of survival curves was rated according to cell lineage and B-cell lymphomas had a better prognosis than T / NK-cell lymphomas. Furthermore, new subtypes in the REAL classification, such as marginal zone B-cell and mantle cell lymphomas, exhibited distinct curves. Taken altogether, the REAL classification demonstrated advantages for assessment of Japanese NHL cases.     

Distribution and prognosis of WHO lymphoma subtypes in Taiwan reveals a low incidence of germinal-center derived tumors

To assess the distribution of lymphomas in Taiwan according to the WHO (World Health Organization) classification, 175 recently diagnosed cases of malignant lymphomas were studied and the clinicopathologic data were analyzed. B-cell lymphomas accounted for 57.1% of cases, T-cell lymphomas 38.9%, and Hodgkin's lymphoma 4%. Extranodal lymphomas predominated (55.4%). The most common subtype of B-cell lymphoma was diffuse large B-cell lymphoma (33.1%). All tumor types believed to be derived from germinal center (GC) B-cells including follicular lymphoma (4.6%), Burkitt lymphoma (1.7%), Hodgkin lymphoma (4.0%), and GC-like diffuse large B-cell lymphoma (as defined by combined expression of bcl-6 and CD10) were rather uncommon as compared to frequencies seen in series from Western countries. The common T-cell lymphomas included nasal and extranasal NK/T cell lymphoma (7.4%), mycosis fungoides (7.4%), and unspecified peripheral T-cell lymphoma (6.9%). Adult T-cell leukemia/lymphoma was very uncommon and accounts for only 0.6%. The proportional increase in T-cell lymphomas that were unrelated to type I human T-cell lymphotropic virus (HTLV-1) may be linked to differential Epstein-Barr virus (EBV) oncogenesis. The survival data revealed that mantle cell lymphoma, NK/T-cell lymphoma, unspecified peripheral T-cell lymphoma, and subcutaneous panniculitis-like T-cell lymphoma had an aggressive course. Our results confirm the utility of the WHO classification scheme for prognostic stratification and further highlight the distinctive distribution pattern of malignant lymphoma in Taiwan including the higher relative incidence of T cell lymphomas and the rarity of germinal center-derived B-cell tumors.     

18F-FDG PET/CT in primary brain lymphoma

The actual role of 18F-FDG PET/CT in evaluating primary brain lymphoma is still an open issue. Brain lymphoma usually show elevated 18F-FDG uptake, often higher than other brain tumors or inflammatory processes, but the metabolic behavior of this lymphoma is not still understood. Our aim was to investigate the particular metabolic behavior of this lymphoma. Forty six patients (21 female, 25 male) with histologically-confirmed brain lymphoma who underwent 18F-FDG PET/CT from vertex to the mid-thigh for initial staging were retrospectively evaluated. The PET images were analyzed visually and semi-quantitatively by measuring the maximum standardized uptake value (SUVmax), lesion-to-liver SUVmax ratio, lesion-to-blood pool SUVmax ratio and the tumor to normal brain uptake ratio (T/N ratio) and compared with epidemiological (age, sex, HIV infection) and morphological (tumor size, MRI appearance) characteristics. Thirty-eight patients (83%) had positive 18F-FDG PET/CT (average SUVmax was 15.6?±?9.2; lesion-to-liver SUVmax ratio 5.8?±?2.8; lesion-to-blood pool SUVmax ratio 7.1?±?3.8, T/N ratio 3.1?±?1.7) at the corresponding brain lesion; the remaining 8 (17%) were not 18F-FDG avid. 18F-FDG avidity was significantly associated with morphological appearance and tumor size and not correlated with other features. 18F-FDG PET/CT detected extracranial disease in two cases (4%) with negative bone marrow biopsies and CT. In conclusion, brain lymphomas are 18F-FDG avid in 83% of cases showing high 18F-FDG uptake and 18F-FDG avidity is correlated with tumor size and morphological appearance of the lesion. PET/CT helped to recognize extracranial disease in two patients.     

Analyses of dose-response in radiotherapy for patients with mature T/NK-cell lymphomas according to the WHO classification.

BACKGROUND AND PURPOSE: This study was conducted to analyze the influence of radiotherapy doses and chemotherapy doses and clinical parameters on in-field disease control in order to assess the optimal radiation doses for treatment of mature T/NK-cell lymphomas according to the newly proposed WHO classification. PATIENTS AND METHODS: Subjects consisted of 62 patients with mature T/NK-cell lymphomas treated with radiotherapy at four Japanese institutions between 1983 and 2002. We reevaluated all histopathological specimens of non-Hodgkin's lymphomas (NHL), using the WHO classification. Radiation therapy was usually delivered to the involved field. The majority of patients also received adriamycin-based chemotherapy such as CHOP, modified CHOP, or more intensive chemotherapy. RESULTS: There were no significant differences in radiosensitivity among subtypes of mature T/NK-cell lymphomas, at least between extranodal NK/T-cell lymphomas, nasal type and peripheral T-cell lymphomas, unspecified. There was a radiation dose-response in non-bulky mature T/NK-cell lymphomas, indicating that radiation doses of more than 52 Gy may be required to obtain in-field control. However, it was difficult to obtain local control of bulky T-cell lymphomas, even with high doses of irradiation. CONCLUSIONS: Mature T/NK-cell lymphomas were more radioresistant than B-cell lymphomas such as diffuse large B-cell lymphomas (DLBCL). The chemotherapy including adriamycin did not improve the in-field control of mature T/NK-cell lymphomas. These results were obtained by using non-randomized data and the significance of these results is limited by bias in data. However, our results suggest that the treatment strategy which is usually used for DLBCL, that is, a combined modality of CHOP and around 40 Gy of radiotherapy, may not be sufficiently effective for mature T/NK-cell lymphomas.     

Fluorodeoxyglucose-positron-emission tomography findings in mantle cell lymphoma

ObjectiveMantle cell lymphoma (MCL) is an aggressive type of non-Hodgkin lymphoma with a propensity for extranodal involvement. The role of fluorodeoxyglucose (FDG)–positron emission tomography (PET) imaging in common types of lymphoma has been well-established. However, there is limited information in the literature about the utility of FDG-PET imaging in patients who have MCL. The aim of this study was to determine the role of FDG-PET imaging in assessment of disease activity in MCL compared with conventional imaging techniques such as computerized tomography/magnetic resonance imaging (CT/MRI).MethodsFDG-PET images of 20 patients with MCL who were referred to our center for assessment of extent of disease were reviewed retrospectively. The FDG-PET findings were compared with those of CT/MRI and were correlated with clinical information, histopathology, and outcome.ResultsThe diagnostic sensitivity for PET was 90% (17/19), and specificity was 100% (1/1). For CT/MRI, the sensitivity was 87% (14/16) and specificity was 50% (2/4). PET was better than CT/MRI in detecting nodal involvement. With respect to extranodal involvement, PET detected more cases of spleen involvement than CT/MRI. PET was equivalent to conventional imaging in detecting bowel involvement.ConclusionsPET imaging has a high sensitivity in detecting both nodal and extranodal involvement in patients who have MCL. Based on the available data in patients who had other subtypes of non-Hodgkin lymphoma, the specificity of PET also appears to be superior to anatomic imaging techniques. FDG-PET imaging may prove to be the single most effective method for detection.