Prognostic impact of pretreatment cell-free DNA concentration in newly diagnosed peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCLs) have a poor prognosis and, to date, there are no reliable predictive biomarkers of response. In this work we explored the prognostic impact of cell-free DNA (cfDNA) concentration in 75 newly diagnosed patients enrolled in a prospective multicenter study. Pre-treatment cfDNA was strongly associated with clinical risk factors and was identified as a superior predictor for shorter progression-free survival in multivariable analysis, outweighing canonical risk parameters. Furthermore, we identified a cfDNA value above which survival worsens. In conclusion, pre-treatment cfDNA concentration represents an easily usable predictive biomarker that is highly associated with survival of PTCL patients.

Dissection of DLBCL microenvironment provides a gene expression-based predictor of survival applicable to formalin-fixed paraffin-embedded tissue.

Background: Gene expression profiling (GEP) studies recognized a prognostic role for tumor microenvironment (TME) in diffuse large B-cell lymphoma (DLBCL), but the routinely adoption of prognostic stromal signatures remains limited. Patients and methods: Here, we applied the computational method CIBERSORT to generate a 1028-gene matrix incorporating signatures of 17 immune and stromal cytotypes. Then, we carried out a deconvolution on publicly available GEP data of 482 untreated DLBCLs to reveal associations between clinical outcomes and proportions of putative tumor-infiltrating cell types. Forty-five genes related to peculiar prognostic cytotypes were selected and their expression digitally quantified by NanoString technology on a validation set of 175 formalin-fixed, paraffin-embedded DLBCLs from two randomized trials. Data from an unsupervised clustering analysis were used to build a model of clustering assignment, whose prognostic value was also assessed on an independent cohort of 40 cases. All tissue samples consisted of pretreatment biopsies of advanced-stage DLBCLs treated by comparable R-CHOP/R-CHOP-like regimens. Results: In silico analysis demonstrated that higher proportion of myofibroblasts (MFs), dendritic cells, and CD4+ T cells correlated with better outcomes and the expression of genes in our panel is associated with a risk of overall and progression-free survival. In a multivariate Cox model, the microenvironment genes retained high prognostic performance independently of the cell-of-origin (COO), and integration of the two prognosticators (COO + TME) improved survival prediction in both validation set and independent cohort. Moreover, the major contribution of MF-related genes to the panel and Gene Set Enrichment Analysis suggested a strong influence of extracellular matrix determinants in DLBCL biology. Conclusions: Our study identified new prognostic categories of DLBCL, providing an easy-to-apply gene panel that powerfully predicts patients' survival. Moreover, owing to its relationship with specific stromal and immune components, the panel may acquire a predictive relevance in clinical trials exploring new drugs with known impact on TME.

A comprehensive review of lenalidomide therapy for B-cell non-Hodgkin lymphoma.

Lenalidomide is an oral non-chemotherapy immunomodulator with direct and indirect effects on non-Hodgkin lymphoma (NHL) cells and with single-agent activity in relapsed/refractory aggressive and indolent B-cell NHL, including mantle cell lymphoma (MCL), diffuse large B-cell lymphoma, and follicular lymphoma. Based on the pivotal phase II MCL-001 trial of lenalidomide in heavily pretreated patients with relapsed/refractory MCL, lenalidomide was approved by the US Food and Drug Administration for the treatment of relapsed/refractory MCL after failure of two prior therapies, one of which includes bortezomib, at a recommended starting dose of 25 mg on days 1-21 of each 28-day cycle. Lenalidomide enhanced the survival benefit in combination with rituximab in preclinical models, prompting clinical evaluation of the lenalidomide-rituximab (R2) combination. In phase II trials, lenalidomide 20 mg on days 1-21 in combination with different standard-dose rituximab schedules exhibited promising activity in both first-line and relapsed/refractory disease across multiple B-cell NHL subtypes. The feasibility of combining lenalidomide with immunochemotherapy, including R-CHOP and rituximab-bendamustine, has been demonstrated in phase I/II trials. These latter regimens are currently being evaluated in ongoing phase II and III trials. The role of lenalidomide monotherapy and R2 in maintenance therapy is also being examined. Based on available evidence, a comprehensive review of lenalidomide in all treatment phases of B-cell NHL-relapsed/refractory disease, first-line, and maintenance-is presented here.

A diachronic-comparative analysis for the identification of the most powerful prognostic index for localized diffuse large B-cell lymphoma.

BACKGROUND: In the rituximab era, the conventional International Prognostic index (IPI) lost at least in part its predictive power, while the National Comprehensive Cancer Network-IPI (NCCN-IPI) seems to be a new and valid prognosticator. However, it has not yet been evaluated in patients with localized disease and it has not been compared with the modified IPI (mIPI) of the pre-rituximab era. In order to evaluate the different prognosticators and to assess the importance of rituximab and radiotherapy (RT), we carried out the so far largest retrospective analysis of patients with localized diffuse large B-cell lymphoma (DLBCL). PATIENTS AND METHODS: We retrospectively assessed clinical and therapeutical data of 1405 patients treated in from 1987 to 2012 in 10 cancer centers in Italy and 1 in Austria. RESULTS: All patients underwent an anthracycline containing polychemotherapy and 254 additional rituximab. The median follow-up was 5.7 years (range 0.1-23 years). The 5-year overall survival (OS) was 75%, being significantly superior in those who underwent additional rituximab, while RT consolidation did not improve the outcome of those who received immunochemotherapy. Patients with extranodal disease benefited from the addition of rituximab, while RT did not improve OS of the immunochemotherapy subgroup. In the pre-rituximab era, the mIPI showed a better performance than the others. In rituximab-treated patients, the NCCN-IPI had the highest discriminant value and the 5-years OS varied significantly (P < 0.001) between the three risk groups and was 98% in low-risk patients, 82% in those with a low-intermediate risk and 57% among high-intermediate and high-risk cases. CONCLUSIONS: The NCCN-IPI is so far the best prognosticator for patients with localized DLBCL who underwent R-CHOP(-like). The addition of rituximab is indispensable regardless of the risk category and site of involvement, while the addition of RT should be reserved to those cases who are ineligible to rituximab.

Antiviral treatment in patients with indolent B-cell lymphomas associated with HCV infection: a study of the Fondazione Italiana Linfomi.

BACKGROUND: Tumor regression after antiviral therapy (AT) is in favor of an etiological role of hepatitis C virus (HCV) in non-Hodgkin's B-cell lymphomas (NHL). PATIENTS AND METHODS: We carried out a cohort study of 704 consecutive HIV-negative, HCV-positive patients with indolent NHL diagnosed and treated from 1993 to 2009 in 39 centers of the Fondazione Italiana Linfomi; 134 patients were managed with AT for lymphoma control. RESULTS: For entire cohort, 5-year overall survival (OS) was 78% [95% confidence interval (CI): 74%-82%] and 5-year progression-free survival (PFS) was 48% (95% CI: 44%-53%). In multivariate analysis, the use of AT during the patients' life had positive impact on OS. Forty-four of the 100 patients treated with first-line AT achieved a complete remission (CR) and 33 a partial response (PR). HCV-RNA clearance was achieved in 80 patients and was related to lymphoma response. At a median follow-up of 3.6 years, 5-year PFS was 63% (95% CI: 50%-73%). CR + PR rate was 85% with AT as second-line treatment. CONCLUSION: AT produces HCV-RNA clearance and consequent tumor regression in most patients with HCV-related indolent NHL. AT used at any time is associated with improved OS. Consequently, AT can be considered an option for patients with indolent lymphomas who do not need immediate cytoreductive treatment.

Central nervous system involvement in mantle cell lymphoma: clinical features, prognostic factors and outcomes from the European Mantle Cell Lymphoma Network.

BACKGROUND: Central nervous system (CNS) involvement in mantle cell lymphoma (MCL) is uncommon, and the manifestations and natural history are not well described. PATIENTS AND METHODS: We present the data on 57 patients with MCL who developed CNS involvement, from a database of 1396 consecutively treated patients at 14 institutions. RESULTS: The crude incidence of CNS involvement was 4.1%, with 0.9% having CNS involvement at diagnosis. Blastoid histology, B-symptoms, elevated lactate dehydrogenase, Eastern Cooperative Group performance status ≥2 and a high Mantle Cell Lymphoma International Prognostic Index score were enriched in the cohort with CNS involvement, and the presence of ≥1 of these features defined a high-risk subset (an actuarial risk of CNS involvement 15% at 5 years) in a single-institution subset. The median time to CNS relapse was 15.2 months, and the median survival from time of CNS diagnosis was 3.7 months. The white blood cell count at diagnosis <10.9 × 109/l, treatment of CNS involvement with high-dose anti-metabolites, consolidation with stem cell transplant and achievement of complete response were all associated with improved survival. CONCLUSIONS: In MCL, CNS involvement is uncommon, although some features may predict risk. Once manifest outlook is poor; however, some patients who receive intensive therapy survive longer than 12 months.

Clinical and molecular characterization of diffuse large B-cell lymphomas with 13q14.3 deletion.

BACKGROUND: Deletions at 13q14.3 are common in chronic lymphocytic leukemia and are also present in diffuse large B-cell lymphomas (DLBCL) but never in immunodeficiency-related DLBCL. To characterize DLBCL with 13q14.3 deletions, we combined genome-wide DNA profiling, gene expression and clinical data in a large DLBCL series treated with rituximab, cyclophosphamide, doxorubicine, vincristine and prednisone repeated every 21 days (R-CHOP21). PATIENTS AND METHODS: Affymetrix GeneChip Human Mapping 250K NspI and U133 plus 2.0 gene were used. MicroRNA (miRNA) expression was studied were by real-time PCR. Median follow-up of patients was 4.9 years. RESULTS: Deletions at 13q14.3, comprising DLEU2/MIR15A/MIR16, occurred in 22/166 (13%) cases. The deletion was wider, including also RB1, in 19/22 cases. Samples with del(13q14.3) had concomitant specific aberrations. No reduced MIR15A/MIR16 expression was observed, but 172 transcripts were significantly differential expressed. Among the deregulated genes, there were RB1 and FAS, both commonly deleted at genomic level. No differences in outcome were observed in patients treated with R-CHOP21. CONCLUSIONS: Cases with 13q14.3 deletions appear as group of DLBCL characterized by common genetic and biologic features. Deletions at 13q14.3 might contribute to DLBCL pathogenesis by two mechanisms: deregulating the cell cycle control mainly due RB1 loss and contributing to immune escape, due to FAS down-regulation.

Nonpegylated liposomal doxorubicin (MyocetTM) combination (R-COMP) chemotherapy in elderly patients with diffuse large B-cell lymphoma (DLBCL): results from the phase II EUR018 trial.

BACKGROUND: To evaluate the activity and safety of nonpegylated liposomal doxorubicin (Myocet) when substituted for doxorubicin in the R-CHOP regimen (R-COMP). PATIENTS AND METHODS: Seventy-five elderly patients with diffuse large B-cell lymphoma (DLBCL) were studied. Only patients with left ventricular ejection fraction (LVEF) > or =50% were allowed. R-COMP regimen was administered every 3 weeks for three cycles, followed by additional five cycles in case of complete response (CR) or partial response. RESULTS: From November 2002 to April 2005, 75 patients were registered, of which 72 were evaluated. Median age was 72 years (range 61-83); 56% of patients had high or high-intermediate International Prognostic Index score. Median LVEF at baseline was 61%. Thirty-eight patients had history of abnormal cardiovascular conditions. The overall response rate was 71%, with a CR rate of 57%. After a median follow-up of 33 months, the 3-year overall survival, failure-free survival, and progression-free survival rates were 72%, 39%, and 69%, respectively. Neutropenia (54%) was the most frequent grade 3-4 adverse event (AE); 21% of patients experienced cardiac AEs, graded as 3-4 in 4% of the cases. CONCLUSION: R-COMP is an effective regimen for the treatment of DLBCL in elderly patients, with an acceptable tolerability profile.

Lenalidomide plus R-CHOP21 in newly diagnosed diffuse large B-cell lymphoma (DLBCL): long-term follow-up results from a combined analysis from two phase 2 trials.

Lenalidomide-RCHOP (R2-CHOP21) has been shown to be safe and effective in patients with untreated diffuse large B-cell lymphoma (DLBCL). The aim of this analysis is to report long-term outcome and toxicities in newly diagnosed DLBCL patients who received R2-CHOP21 in two independent phase 2 trials, conducted by Mayo Clinic (MC) and Fondazione Italiana Linfomi (FIL). All patients received R-CHOP21 plus lenalidomide. Long-term progression-free survival (PFS), time to progression (TTP), overall survival (OS) and late toxicities and second tumors were analyzed. Hundred and twelve patients (63 MC, 49 FIL) were included. Median age was 69 years, 88% were stage III-IV. At a median follow-up of 5.1 years, 5y-PFS was 63.5%, 5y-TTP 70.1% and 5y-OS 75.4%; according to cell of origin (COO): 5y-PFS 52.8% vs 64.5%, 5y-TTP 61.6% vs 69.6% and 5y-OS 68.6% vs 74.1% in germinal center (GCB) vs non-GCB respectively. Four patients experienced grade 4-5 late toxicities. Grade ≤ 3 toxicities were infections (N = 4), thrombosis (N = 1) and neuropathy (N = 3). Seven seconds tumors were observed. Long-term follow-up demonstrates that R2-CHOP21 efficacy was maintained with high rates of PFS, TTP, and OS. Lenalidomide appears to mitigate the negative prognosis of non-GCB phenotype. Incidence of therapy-related secondary malignancies and late toxicities were low.

PO-03 - Khorana score and histotype predict the incidence of early venous thromboembolism (VTE) in Non Hodgkin Lymphoma (NHL). A pooled data analysis of twelve clinical trials of Fondazione Italiana Linfomi (FIL).

BACKGROUND: Recent studies show that the risk of VTE in NHL pts is similar to that observed in high risk solid tumors (i.e. pancreatic, ovarian cancer). VTE in NHL occurs in most cases within three months from diagnosis and can have substantial impact on treatment delivery and outcome as well as on quality of life. However few data are available on potential predictors. AIMS: To better clarify the epidemiology of early (within six months from treatment start) VTE in NHL we conducted a pooled data analysis of 12 clinical trials from FIL. Our analysis included basic demographic features, lymphoma-related characteristics as well the Khorana score (based on histology, BMI, platelets WBC and HB counts) which is extensively used in solid tumors to predict VTE risk. PATIENTS AND METHODS: From Jan. 2010 to Dec. 2014, all pts with B-cell NHL enrolled in prospective clinical trials from FIL for frontline treatment were included. For 9 studies study period included the entire trial population was included. The analyses were conducted based on CRFs as well as pharmacovigilance reports. VTE definition and grading was stated according to standard criteria of toxicity (CTCAE V4.0). Cumulative incidence of VTE from the study enrollment was estimated using the method described by Gooley et al. accounting for death from any causes as a competing risk. The Fine & Gray survival model was used to identify predictors of VTE among NHL pts. Factors predicting the grade of VTE were investigated using an ordinal logistic regression model. This pooled data analysis was approved by local IRB. RESULTS: Overall, 1,717 patients belonging to 12 studies were evaluated. Eight were phase I/II or II (25% of pts) and 4 phase III (75% of pts). M/F ratio was 1.41, Median age was 57, (IQ range (IQR) 49-66). Histologies were: DLCL-B 34%, FL 41%, MCL 18%, other 6%. Median BMI was 25 (IQR 22-28). Median Hb, WBC and platelets counts were 13g/dl) (IQR 11.5-14.2), 7.1*10^(9)/l (IQR 5.6-10.3), 224*10^(9)/l (IQR 169-298), respectively. 1189 pts were evaluable Khorana score: 58% low risk, 30% intermediate risk, 12% were high risk. Human erythropoetin support was given to 9% of patients. All pts received Rituximab. Planned therapeutic programs included ASCT in 27% of pts, conventional chemotherapy in 67% a conventional chemotherapy plus lenalidomide in 6%. Overall 59 any grade VTE episodes occurred in 51 pts (2.9%), including 21 grade III-IV VTE (18 pts). None was fatal. Median time from study enrolment to VTE was 63 days (IQR: 35-110). Considering death as a competitive event the 6 months cumulative incidence of VTE was 2,2% in low risk Khorana score, 4.5% (95%IC: 2.3-6.7) in intermediate and 6.6% (95%IC: 2.4-10.8) in high risk (p=0.012) (figure 1). Khorana score was predictive also for grade III-IV events as they were 0,7% (95% CI:0.1-1.4) in low risk and 2.0% (95% CI:0.8-3.3) in intermediate-high risk (p=0.048). The results were similar also after excluding lenalidomide containing studies. The Fine and Gray multivariate analyses, adjusted for age and stage, showed that Khorana score (intermediate risk adjHR=1.96; 95%IC: 0.84-4.56 and high risk adjHR=3.81; 95%IC: 1.51-9.58) and DLCL-B histotype (adjHR=2.58; 95% CI: 1.01-6.55) were independently associated to an increased risk of VTE. Moreover an ordinal logistical regression model indicated that the increase of one point in the Khorana score resulted in an increased risk of VTE (OR=1.85; 95% CI: 1.23-2.79). CONCLUSIONS: Our results suggest that DLCL-B histotype and Khorana score are predictors of VTE in NHL. The latter might become a simple and effective tool to assess the risk of VTE in NHL. Prospective validation including also patients not eligible for clinical trials is needed.

Using PET-CT in the restaging of primitive mediastinal B-cell lymphoma (PMBCL) after chemotherapy: which criteria should we use?

AIM: Primitive mediastinal B-cell lymphoma (PMBCL) is a relatively rare form of non-Hodgkin lymphoma (NHL), typically concerning the youngster, with an aggressive course and poor prognosis. The therapy generally consists of high dose chemotherapy followed by radiotherapy. PET-CT is used at staging, restaging after chemotherapy and after radiotherapy, or when relapse is suspected. Aim of the study was to compare different criteria in the evaluation of response to chemotherapy in this setting. METHODS: Thirty-eight patients with PMBCL (15 M, 23 F, median age 33 yrs [range 18-79]), all treated with chemo-immunotherapy and radiotherapy, who had undergone baseline (b-PET) and end of chemotherapy (f-CHT-PET) 18F-FDG-PET-CT scans at our institution between July 2004 and September 2014 were retrospectively re-evaluated; the median follow-up was 42 months (range 4-109), at which 4/38 (11%) had died, 5/38 (13%) were in partial response (PR) and 29/38 (76%) were in complete response (CR). The primary endpoint was progression-free survival (PFS), while the secondary one was overall survival (OS), according to the Cheson criteria. SUV max of the mediastinal disease mass at staging, of the residual mass at CT after chemo-immunotherapy, SUV max of the liver and of the mediastinal blood pool (MBP) were calculated for all patients. RESULTS: In our population, we observed that: 1) visual criteria performs better when positivity-negativity threshold is set at point 3 of the 5-point scale (5-PS); 2) semiquantitative approach by use of Δ SUV max performs better when the threshold is set at 66% decrease: in fact, at Δ SUV max analysis with 66% decrease, 9 patients resulted positive at the test (Δ SUV max ≤66%), 29 negative (Δ SUV max >66%). CONCLUSION: In our population Δ SUV max could be working well in these patients because the baseline values are very high and very homogeneous. Our data, though limited in numerosity of patients and events, suggests that in this particular setting the use of the 5-PS reporting system could not be the best tool available; on the other hand, Δ SUV max could prove to be reliable in the evaluation of response to chemotherapy.

Inter- and intratumoral heterogeneity of BCL2 correlates with IgH expression and prognosis in follicular lymphoma.

Most follicular lymphomas (FLs) are genetically defined by the t(14;18)(q32;q21) translocation that juxtaposes the BCL2 gene to the immunoglobulin heavy chain (IgH) 3' regulatory regions (IgH-3'RRs). Despite this recurrent translocation, FL cases are heterogeneous in terms of intratumoral clonal diversity for acquired mutations and variations in the tumor microenvironment. Here we describe an additional mechanism that contributes to inter- and intratumoral heterogeneity in FLs. By applying a novel single-molecule RNA fluorescence-based in situ hybridization (FISH) technique to detect mRNA molecules of BCL2 and IgH in single cells, we found marked heterogeneity in the number of BCL2 mRNA transcripts within individual lymphoma cells. Moreover, BCL2 mRNA molecules correlated with IgH mRNA molecules in individual cells both in t(14;18) lymphoma cell lines and in patient samples. Consistently, a strong correlation between BCL2 and IgH protein levels was found in a series of 205 primary FL cases by flow cytometry and immunohistochemistry. Inter- and intratumoral heterogeneity of BCL2 expression determined resistance to drugs commonly used in FL treatment and affected overall survival of FL patients. These data demonstrate that BCL2 and IgH expressions are heterogeneous and coregulated in t(14;18)-translocated cells, and determine the response to therapy in FL patients.

Analysis of the host pharmacogenetic background for prediction of outcome and toxicity in diffuse large B-cell lymphoma treated with R-CHOP21.

Knowledge on the impact of pharmacogenetics in predicting outcome and toxicity in diffuse large B-cell lymphoma (DLBCL) is scant. We tested 106 consecutive DLBCL treated with R-CHOP21 for 19 single nucleotide polymorphisms (SNPs) from 15 genes potentially relevant to rituximab-CHOP (R-CHOP) pharmacogenetics. Associations of SNPs with event-free survival (EFS) and toxicity were controlled for multiple testing. Genotypic variants of nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase p22phox (CYBA rs4673) and alpha1 class glutathione S-transferase (GSTA1 rs3957357) were independent predictors of EFS (CYBA rs4673 TT genotype: HR 2.06, P=0.038; GSTA1 rs3957357 CT/TT genotypes: HR 0.38, P=0.003), after adjusting for International Prognostic Index (IPI). CYBA rs4673 and GSTA1 rs3957357 also predicted outcome in DLBCL subgroups by IPI. Impact of SNPs on toxicity was evaluated in 658 R-CHOP21 courses utilizing generalized estimating equations. NCF4 rs1883112 was an independent predictor against hematologic (odds ratios (OR): 0.45; P=0.018), infectious (OR: 0.46; P=0.003) and cardiac toxicity (OR: 0.37; P=0.023). Overall, host SNPs affecting doxorubicin pharmacodynamics (CYBA rs4673) and alkylator detoxification (GSTA1 rs3957357) may predict outcome in R-CHOP21-treated DLBCL. Also, NCF4 rs1883112, a SNP of NAD(P)H oxidase p40phox, may have a function in protecting against hematologic and nonhematologic toxicity. These results highlight the need to improve characterization of the host genetic background for a better prognostication of DLBCL.

FDG-PET in the detection of bone marrow disease in Hodgkin's disease and aggressive non-Hodgkin's lymphoma and its impact on clinical management.

AIM: Identification of bone marrow disease (BMD) is a crucial step in the diagnostic work-up of patients with lymphoma. In lymphoma staging, bone marrow biopsy (BMb) is considered as the gold standard, despite its limitations. The aim of this study was to compare the usefulness of 2-deoxy-2-[(18)F]fluoro-D-glucose positron emission tomography (FDG-PET) vs BMb in the detection of BMD in patients with Hodgkin's disease (HL) or aggressive non-Hodgkin's lymphoma (NHL) and its impact on therapy. METHODS: A total of 194 consecutive patients with malignant lymphoma were referred for staging. The clinical stage was defined according to the Ann Arbor classification by means of contrast enhanced computed tomography (CT), BMb and whole body FDG-PET/CT scan. Sensitivity, specificity, accuracy in BMD evaluation were calculated for PET and BMb. RESULTS: FDG-PET vs BMb: sensitivity 65.3% vs 55.1%; specificity 98.6% vs 100%; accuracy 90.2% vs 88.7%; positive and negative predictive value 94.1% and 89.3% vs 100% and 86.8%, respectively. Although PET and BMb had similar sensitivity and accuracy, BMD was identified by both methods in only 10 out of 49 patients. There were no significant differences in PET and BMb accuracy between the HL and the NHL patients. Moreover, treatment regimen was changed in 12 patients on the basis of FDG-PET findings. CONCLUSION: Our study demonstrates that BMb and FDG-PET are complementary in the evaluation of BMD. FDG-PET improves the sensitivity of BMb, especially in the presence of focal BMD. Performing FDG-PET before BMb is advised for optimal biopsy site targeting.

Role of whole-body [18F] fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and conventional techniques in the staging of patients with Hodgkin and aggressive non Hodgkin lymphoma.

PURPOSE: The aim of this study was to evaluate the role of [(18)F]fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in the staging of Hodgkin's and aggressive non-Hodgkin's lymphoma (HL and NHL), comparing it with conventional diagnostic methods, i.e. contrast-enhanced CT and bone marrow biopsy. MATERIALS AND METHODS: Sixty-five consecutive patients (30 HL and 35 NHL) who underwent conventional disease staging and FDG-PET/CT were included. Concordance between conventional methods and PET was established when both procedures identified the same disease stage. Discordant findings were investigated further by using other diagnostic techniques (ultrasonography or magnetic resonance imaging) and/or clinical follow-up. RESULTS: PET correctly staged 93.8% of enrolled patients (61/65), whereas conventional techniques correctly staged 89.2% (58/65; p=NS, Chi(2) test). There was complete concordance in 54/65 patients (83.1%); among the remaining 11 cases, PET upstaged eight patients (seven true positive and one false positive), and downstaged three (all false negative). In 5/65 patients, chemotherapy treatment was modified on the basis of PET findings. CONCLUSIONS: Our data confirm the high accuracy of FDG-PET/CT in staging HL and NHL. FDG-PET/CT should therefore be used routinely in the initial evaluation of both patient subgroups.