Human Papillomavirus and Epstein-Barr virus co-infection in Cervical Carcinoma in Algerian women

Purpose

To present a possible coincidence of cytomegalovirus retinitis and intraocular lymphoma in a patient with systemic non-Hodgkin’s lymphoma.

Case presentation

A 47-year-old woman presented with decreased visual acuity associated with white retinal lesions in both eyes. A history of pneumonia of unknown aetiology closely preceded the deterioration of vision. Five years previously the patient was diagnosed with follicular non-Hodgkin’s lymphoma. She was treated with a chemotherapy regimen comprised of cyclophosphamide, adriamycin, vincristin, and prednisone with later addition of the anti-CD20 antibody rituximab. She experienced a relapse 19 months later with involvement of the retroperitoneal lymph nodes, and commenced treatment with rituximab and ⁹⁰Y-ibritumomab tiuxetan. A second relapse occurred 22 months after radioimmunotherapy and was treated with a combination of fludarabine, cyclophosphamide, and mitoxantrone followed by rituximab. The patient experienced no further relapses until the current presentation (April, 2010). Pars plana vitrectomy with vitreous fluid analysis was performed in the right eye. PCR testing confirmed the presence of cytomegalovirus in the vitreous. Atypical lymphoid elements, highly suspicious of malignancy were also found on cytologic examination. Intravenous foscarnet was administered continually for three weeks, followed by oral valganciclovir given in a dose of 900 mg twice per day. In addition, the rituximab therapy continued at three monthly intervals. Nevertheless, cessation of foscarnet therapy was followed by a recurrence of retinitis on three separate occasions during a 3-month period instigating its reinduction to the treatment regime after each recurrence.

Conclusions

Cytomegalovirus retinitis is an opportunistic infection found in AIDS patients as well as in bone marrow and solid organ transplant recipients being treated with systemic immunosuppressive drugs. This case presents a less common incidence of cytomegalovirus retinitis occurring in a patient with non-Hodgkin’s lymphoma. We demonstrated a possible coexistence of cytomegalovirus retinitis and intraocular lymphoma in this particular patient. The final diagnosis was based on clinical manifestations together with the course of uveitis and its response to treatment alongside the results of vitreous fluid analysis. This report highlights the importance of intraocular fluid examination in cases with nonspecific clinical manifestations. Such an examination allows for the detection of simultaneously ongoing ocular diseases of differing aetiologies and enables the prompt initiation of effective treatment.     

Use of radioimmunotherapy in stem cell transplantation and posttransplantation: focus on yttrium 90 ibritumomab tiuxetan

Although autologous stem cell transplantation (ASCT) produces prolonged disease-free survival in many patients with non-Hodgkin's lymphoma (NHL), relapse remains the most common cause of treatment failure. Because of the potential benefit of adding targeted irradiation to conditioning regimens, clinical trials are testing the safety and efficacy of combining radioimmunotherapy with yttrium 90 ibritumomab tiuxetan or iodine 131 tositumomab and chemotherapy, either as replacement for total body irradiation or in addition to standard high-dose chemotherapy (HDC) regimens. Current strategies include using standard or escalated doses of radioimmunoconjugates with HDC before ASCT in patients with relapsed or refractory B-cell NHL. We reviewed the safety and efficacy of (90)Y ibritumomab tiuxetan as part of the conditioning regimen before ASCT. Preliminary data from phase 1 and 2 trials show that (90)Y ibritumomab tiuxetan may be safely added to HDC preparative regimens for high-risk B-cell NHL. Additionally, comparisons of outcomes with radioimmunotherapy and ASCT with historical controls suggest that it may be more effective than conventional regimens. Results of (90)Y ibritumomab tiuxetan alone posttransplantation in select patients who have relapsed after HDC and ASCT are also encouraging. Studies of (90)Y ibritumomab tiuxetan in the setting of allogeneic stem cell transplantation appear promising as well.     

Stratégies de consolidation par Zevalin® en traitement des lymphomes malins non Hodgkiniens

Radio-immunotherapy with ⁹⁰Y-ibritumomab tiuxetan (Zevalin^®) has been first approved in 2004 as a treatment for patients with relapsed/refractory non-Hodgkin follicular lymphoma (FL). In April 2008, the label has been extended to the consolidation therapy after remission induction in previously untreated patients with FL on the basis of the First-line indolent trial (FIT) phase III randomised study of Zevalin^® as front-line consolidation versus no further treatment. Consolidation of first remission with Zevalin^® (15 MBq/kg), 6 to 12 weeks after the last chemotherapy dose in advanced-stage FL is highly effective with no unexpected toxicities, prolonging PFS by 2 years and resulting in 77% PR-to-CR conversion rates regardless of type of first-line induction treatment. An assessment of the dosimetry of 90-Y ibritumomab tiuxetan in the FIT study indicated that consolidation treatment was safe in all patients, including those with a CR after induction therapy. The consolidation strategy with Zevalin^®, as a single agent or combined with high-dose chemotherapy followed by autologous stem cell transplantation is currently investigated in other types of B-cell lymphomas.     

Intérêt de la TEP au 18F-FDG préthérapeutique pour prédire la réponse à la radio-immunothérapie dans les lymphomes non hodgkiniens

PurposeRadioimmunotherapy (RIT) is a new treatment option for patients with non-Hodgkin lymphoma (NHL). Response to RIT currently remains difficult to predict using conventional prognostic factors and could be refined using functional imaging. The goal of this work is to evaluate the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) in predicting response to yttrium 90-labeled monoclonal antibodies for patients with NHL.MethodThirty-five patients with NHL who had undergone 18F-FDG PET prior to RIT with either 90Y-ibritumomab tiuxetan or 90Y-epratuzumab tetraxetan were included in this retrospective study. Four functional criteria (SUVmax, SUVmean, volume and the product of the volume and the SUVmean-TLG-) were analyzed on a per-lesion basis.ResultsA total of 154 lesions were analysed. The per-lesion analysis revealed significant differences (P < 0.05) between responders and non-responders for several criteria and above all for the SUV.ConclusionOur results suggest a predictive role of 18F-FDG PET prior to RIT by giving a useful indication of the radiosensitivity of the lymphoma.     

Quelques perspectives concernant le traitement des lymphomes par Zevalin® à partir de l’évaluation de l’expérience niçoise

Zevalin^® (yttrium-90 ibritumomab-tiuxetan) is the first radioimmunotherapy authorized in France for non-Hodgkin's lymphoma (NHL) treatment. It is indicated for clinical use in adults for recurrent or refractory follicular NHL including those refractory to rituximab. Treatment responses are between 70 and 80%. Since three years, 13 patients were treated in Nice by Zevalin^®. From this retrospective study, we discuss the various perspectives of this treatment. The majority of our patients in this study were evaluated by 18-FDG–PET and we also evaluated our results in this regard. Even if our follow-up is short, our experience confirms the efficacy and tolerance of Zevalin^® treatment in multirecurrent follicular NHL including those refractory to rituximab. The treatment is of interest in elderly patients and in case of autologous stem cell transplant. The proposed « Autorisation de Mise sur le Marché » (AMM) indication is probably not the best one since efficacy seems better in smaller tumour volumes and when used earlier in the therapeutic course. Zevalin^® will probably be more beneficial in first line treatment, for immunochemotherapy consolidation and for autologous stem cell transplant conditioning. We pointed out the prognostic value of FDG–PET for early post-treatment evaluation, one to two months after Zevalin^® administration. However, larger scale studies are necessary to confirm these findings.     

Carcinoma and multiple lymphomas in one patient: establishing the diagnoses and analyzing risk factors

Multiple malignancies may occur in the same patient, and a few reports describe cases with multiple hematologic and non-hematologic neoplasms. We report the case of a patient who showed the sequential occurrence of four different lymphoid neoplasms together with a squamous cell carcinoma of the lung. A 62-year-old man with adenopathy was admitted to the hospital, and lymph node biopsy was positive for low-grade follicular lymphoma. He achieved a partial remission with chemotherapy. Two years later, a PET-CT scan showed a left hilar mass in the lung; biopsy showed a squamous cell carcinoma. Simultaneously, he was diagnosed with diffuse large B cell lymphoma in a neck lymph node; after chemo- and radiotherapy, he achieved a complete response. A restaging PET-CT scan 2 years later revealed a retroperitoneal nodule, and biopsy again showed a low-grade follicular lymphoma, while a biopsy of a cutaneous scalp lesion showed a CD30-positive peripheral T cell lymphoma. After some months, a liver biopsy and a right cervical lymph node biopsy showed a CD30-positive peripheral T cell lymphoma consistent with anaplastic lymphoma kinase-negative anaplastic large cell lymphoma. Flow cytometry and cytogenetic and molecular genetic analysis performed at diagnosis and during the patient’s follow-up confirmed the presence of two clonally distinct B cell lymphomas, while the two T cell neoplasms were confirmed to be clonally related. We discuss the relationship between multiple neoplasms occurring in the same patient and the various possible risk factors involved in their development.     

Apport de la tomographie à émission de positons au 18F-fluorodéoxyglucose dans la prise en charge des lymphomes folliculaires

PurposeTo assess the usefulness of positron emission tomography/computed tomography in staging, prognosis evaluation and restaging of patients with follicular lymphoma.Patients and methodsa retrospective study was performed on 45 patients with untreated biopsy-proven follicular lymphoma who underwent FDG-PET/CT and CT before and after chemo-immunotherapy induction treatment (rituximab combined with cyclophosphamide, doxorubicin, vincristine and prednisone).ResultsPET/CT detected more nodal (+51%) and extranodal (+89%) lesions than CT. PET/CT changed Ann Arbor stage in eight patients (18%). Five patients (11%) initially considered with early stage (I/II) were finally managed as advanced stage (III/IV). In this study, initial PET/CT was significantly more accurate to identify patients with poor prognosis than FLIPI. Poor prognosis was defined as incomplete therapeutic response or early relapse. Accuracy of PET/CT for therapeutic response assessment was significantly higher than that of CT (0.97 vs 0.64), especially because of its ability to identify inactive residual masses. Beside, post-treatment PET/CT was able to predict patients’ outcome. The median progression free survival (PFS) was 48 months in the PET/CT negative group as compared to 17.2 months for the group with residual uptake (P < 10^?4).ConclusionFDG-PET/CT is a very useful tool for staging, assessing prognosis and therapeutic response of patients with follicular lymphoma.     

Semiautomatic algorithm for lymph node analysis corrected for partial volume effects in combined positron emission tomography-computed tomography

Positron emission tomography-computed tomography (PET-CT) is superior compared to stand-alone PET in evaluation of malignancies. Few studies have employed high-resolution structural information to correct PET. We designed a semiautomatic algorithm using CT and PET to obtain a partial volume corrected (PVC) standardized uptake value (SUV) and a combined morphologic and functional parameter (multimodal SUV) for lymph node assessment. Lesions were segmented by a semiautomatic algorithm in CT images. Lesion volume was used for PVC and for calculating the multimodal SUV. The method was applied to 47 lymph nodes (30 patients) characterized as suspicious in 18F-fluorodeoxyglucose-PET-CT. In phantoms, PVC improved significantly the measured uptake of the lesion. In patients, 36 lymph nodes could be segmented without problems; in 11 lesions, a manual interaction was necessary. SUVs before PVC (mean 1.29) increased significantly (p < .0005) after PVC (mean 2.8). If SUV 2.5 was used as a threshold value to distinguish between benign and malignant lesions, 11 of the 47 lesions changed from benign to malignant after the PVC. The mean multimodal SUV was 0.39 mL for the benign lesions and 4.47 mL for the malignant lesions. In this work we presented a method for quantitative analysis of lymph nodes in PET-CT. PVC leads to significant differences in SUV.     

La radio-immunothérapie

Radioimmunotherapy (RIT) is a new modality of targeted therapy in which irradiation from radionuclides is delivered to tumor targets using monoclonal antibodies (MAb) directed to tumor-associated antigen. RIT has been developed for more than 20 years. Today, RIT can be used in clinical practice using non-ablative activity of murine anti-CD20 ⁹⁰Y-ibritumomab tiuxetan (ZevalinÒ) for treatment of patients with relapsed or refractory FL, with overall response rate of 70 to 80% and 20 to 30% of complete response. Different approaches are explored to improve efficacy of RIT in NHL: myeloablative RIT or HD treatment, RIT as consolidation after chemotherapy to target MRD, RIT in first-line treatment, fractionated RIT, RIT using other Ag targets. For solid tumors, interesting results have been obtained using anti-CEA RIT delivered as consolidation treatment or using pretargeting system.     

Stereotactic radiotherapy for oligometastases in the lymph nodes

Even though systemic therapy is standard treatment for lymph node metastases, metastasis-directed stereotactic radiotherapy (SRT ) seems to be a valid option in oligometastatic patients with a low disease burden.Positron emission tomography-computed tomography (PET-CT ) is the gold standard for assessing metastases to the lymph nodes; co-registration of PET-CT images and planning CT images are the basis for gross tumor volume (GTV ) delineation. Appropriate techniques are needed to overcome target motion. SRT schedules depend on the irradiation site, target volume and dose constraints to the organs at risk (OARs) of toxicity. Although several fractionation schemes were reported, total doses of 48–60 Gy in 4–8 fractions were proposed for mediastinal lymph node SRT, with the spinal cord, esophagus, heart and proximal bronchial tree being the dose limiting OAR s. Total doses ranged from 30 to 45 Gy, with daily fractions of 7–12 Gy for abdominal lymph nodes, with dose limiting OARs being the liver, kidneys, bowel and bladder. SRT on lymph node metastases is safe; late side effects, particularly severe, are rare.     

The role of PET-CT scan with somatostatin analogue labelled with gallium-68 (⁶⁸Ga-DOTA-TATE PET-CT) in diagnosing patients with disseminated medullary thyroid carcinoma (MTC)

INTRODUCTION: Calcitonin is a very sensitive marker of medullary thyroid carcinoma (MTC). High concentrations of basal or pentagastrin stimulated calcitonin in patients with MTC is a signal of recurrence or metastatic disease. Detection of metastatic foci remains a diagnostic and therapeutic challenge. The aim of the study was to present examples of the use of ??Ga-DOTA-TATE PET-CT examinations in the diagnosis of patients with MTC and concomitant elevated serum calcitonin concentrations. Initially the study involved eight patients with MTC and elevated basal or stimulated calcitonin, in which earlier diagnostic imaging was negative for metastasis: neck ultrasound, chest and mediastinal CT scan, liver MRI, bone scintigraphy, and 1?F-FDG-PET. A total body scan was performed using ??Ga-DOTA-TATE PET-CT. Two patients with positive diagnostic imaging tests were referred for surgery including resection of cervical lymph nodes with histopathological examination for assessment of metastases. CONCLUSIONS: On the basis of the presented cases we conclude that PET-CT scan with somatostatin analogue labelled with gallium (??Ga-DOTA-TATE PET-CT) may be useful in the diagnostic imaging of patients with disseminated MTC.     

Early positron emission tomography/computed tomography as a predictor of response after CTL019 chimeric antigen receptor –T-cell therapy in B-cell non-Hodgkin lymphomas

Molecular imaging with ¹⁸F-Fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is an established modality for response assessment in patients with lymphoma undergoing treatment. However, patients treated with novel immunotherapies may have false-positive PET/CT findings due to tumor site and systemic inflammation. In particular, treatment with autologous chimeric antigen receptor modified T-cells redirected at CD19 (CTL019 CAR-T cells) is often complicated by “cytokine release syndrome” (CRS) due to a severe systemic inflammatory reaction. Infiltration of tumors by activated CTL019 cells may impact radiographic and functional imaging findings. The role of PET/CT in patients treated with CTL019 has not previously been described. We performed a pilot, single-arm, prospective study to explore the utility of early PET/CT in patients with diffuse large B-cell lymphoma (DLBCL) and follicular lymphoma (FL) undergoing treatment with CTL019 CAR-T cells. Patients had PET/CT prior to CTL019 infusion and then early PET/CT at 1 month after treatment. The primary outcome was the amount/change in metabolically active tumor volume (MTV) and FDG uptake. We enrolled seven patients (DLBCL, three; FL, four). Six of 7 had baseline PET/CT with active disease. On post-treatment PET/CT, three patients had no residual MTV, two patients had a decrease in MTV and two patients had an increase in MTV. The three patients with no residual MTV all remain in remission >2 years post-treatment. The patients with less than complete response all subsequently relapsed. Development of CRS did not confound PET/CT findings. In patients with DLBCL and FL receiving CTL019 CAR-T cells, early PET/CT may predict response to this novel immunotherapy.     

Stereotactic radiotherapy for lung oligometastases

30–60% of cancer patients develop lung metastases, mostly from primary tumors in the colon-rectum, lung, head and neck area, breast and kidney. Nowadays, stereotactic radiotherapy (SRT ) is considered the ideal modality for treating pulmonary metastases.When lung metastases are suspected, complete disease staging includes a total body computed tomography (CT ) and/or positron emission tomography-computed tomography (PET -CT ) scan. PET -CT has higher specificity and sensitivity than a CT scan when investigating mediastinal lymph nodes, diagnosing a solitary lung lesion and detecting distant metastases. For treatment planning, a multi-detector planning CT scan of the entire chest is usually performed, with or without intravenous contrast media or esophageal lumen opacification, especially when central lesions have to be irradiated. Respiratory management is recommended in lung SRT, taking the breath cycle into account in planning and delivery. For contouring, co-registration and/or matching planning CT and diagnostic images (as provided by contrast enhanced CT or PET-CT ) are useful, particularly for central tumors. Doses and fractionation schedules are heterogeneous, ranging from 33 to 60 Gy in 3–6 fractions. Independently of fractionation schedule, a BED₁₀ > 100 Gy is recommended for high local control rates. Single fraction SRT (ranges 15–30 Gy) is occasionally administered, particularly for small lesions. SRT provides tumor control rates of up to 91% at 3 years, with limited toxicities.The present overview focuses on technical and clinical aspects related to treatment planning, dose constraints, outcome and toxicity of SRT for lung metastases.     

Confirmation of histology of PET positive lymph nodes recovered by hand-video-assisted thoracoscopy surgery

PET/CT (Positron Emission Tomography-Computed Tomography) is an advanced diagnostic imaging device that combines both PET and an X-ray CT. This study evaluates the effects of PET/CT on detecting primary tumors and metastases, and looks at the therapeutic effect of minimally invasive surgery on esophageal cancer patients. Eighty patients with esophageal cancer were enrolled in the study between January, 2004 and December, 2007, who were randomly divided into two groups of 40, one of which was treated with hand-video-assisted thoracoscopy surgery (HVATS) esophagectomy and one of which was treated with conventional surgery. All patients underwent a PET/CT scan 2-3weeks before their operation, and their cervical, thoracic and upper abdominal lymph nodes were biopsied. All the primary esophageal lesions showed high FDG uptake. The maximum standardized uptake value (SUV) was 3.78-25.64 (11.73±5.32), while the mean SUV was 3.65=16.92 (9.12±4.37). Using 2.5 as the SUV standard, all esophageal lesions were detected by PET/CT image. Of the 80 patients, 53 had lymph nodal metastases, with a total of 142 metastatic lymph nodes, which showed high FDG uptake. The maximum SUV was 2.77-14.63 (7.98±3.25), and the mean SUV was 2.31-12.84 (5.34±3.19). The visual analysis from the PET/CT scan showed a sensitivity of 86.62%, a specificity of 95.85%, a positive predictive value of 93.89%, a negative predictive value of 90.69% and an accuracy of 91.94%. The PET/CT scan showed a high sensitivity and specificity in detecting primary esophageal cancer and lymph nodal metastases. The mean post-surgery life expectancies for patients undergoing HVATS and conventional surgery are 27.93months and 28.05months, respectively. The two groups showed no statistically significant difference. We thus conclude that PET/CT combined with HVATS is a new choice for esophageal carcinoma patients.     

原发性胃淋巴瘤临床与内镜特征分析

目的:探讨影像学检查及胃镜、超声内镜对原发性胃淋巴瘤的术前诊断方法,以提高该疾病的术前诊断率。方法:总结我院经手术及病理证实的21例原发性胃淋巴瘤资料,评估胃镜活检、超声内镜及CT对该病诊断的作用。结果:21例术前CT检查,误诊为浸润型胃癌11例,间质瘤2例,未见明显异常3例。CT术前诊断率为23.8%(5/21)。全部患者均实施胃镜检查,活检病理诊断淋巴瘤14例,胃镜活检诊断率为66.7%(14/21)。其中10名患者实施超声胃镜检查,判断胃淋巴瘤6例、胃癌3例、间质瘤1例;术前诊断率为60.0%(6/10)。结论:胃镜及超声内镜是原发性胃淋巴瘤的主要术前诊断方式;CT扫描能明确有无纵隔及腹腔内淋巴结肿大,为原发性胃淋巴瘤提供诊断依据。     

Silencing of Human Phosphatidylethanolamine-Binding Protein 4 Enhances Rituximab-Induced Death and Chemosensitization in B-Cell Lymphoma

Rituximab is the first line drug to treat non Hodgkin’s lymphoma (B-NHL) alone or in combination with chemotherapy. However, 30–40% of B-NHL patients are unresponsive to rituximab or resistant after therapy. Human phosphatidylethanolamine-binding protein 4 (hPEBP4) is a novel member of PEBP family and functions as an anti-apoptotic molecule. In this study, we found hPEBP4 to be expressed in up to 90% of B-cell lymphoma patients, but in only 16.7% of normal lymph nodes. Interestingly, hPEBP4 overexpression inhibited rituximab-mediated complement dependent cytotoxicity (R-CDC) and antibody-dependent cell-mediated cytotoxicity (ADCC) in B-NHL cells while downregulation of hPEBP4 augmented the therapeutic efficacy of rituximab both in vitro and in vivo. Furthermore, hPEBP4 silencing sensitized the primary B-acute lymphocytic leukemia (B-ALL) cells to R-CDC. During rituximab-mediated complement dependent cytotoxicity, hPEBP4 was recruited to the cell membrane in a PE-binding domain dependent manner and inhibited R-CDC induced calcium flux and reactive oxygen species (ROS) generation. These events contributed to the decrease of cell death induced by R-CDC in B-cell lymphomas. Meanwhile, hPEBP4 knockdown potentiated the chemosensitization of the rituximab in B-cell lymphoma cells by regulating the expression of Bcl-xl, Cycline E, p21^waf/cip1 and p53 and the activation of caspase-3 and caspase-9. Considering that hPEBP4 conferred cellular resistance to rituximab treatment and was preferentially expressed in lymphoma tissue, it could be a potential valuable target for adjuvant therapy for B-cell lymphoma.     

Radioimmunotherapy of non-Hodgkin's lymphoma: from the 'magic bullets' to 'radioactive magic bullets'

Radioimmunotherapy (RIT) of lymphoma with Zevalin and Bexxar was approved by FDA in 2002 and 2003, respectively, for the treatment of relapsed or refractory CD20+ follicular B-cell non-Hodgkin′s lymphoma. In 2009, Zevalin was also approved for consolidation therapy in patients with follicular non-Hodgkin's lymphoma that achieve a partial or complete response to first-line chemotherapy. For follicular lymphoma patients, the overall response and progression-free survival rates have significantly improved since the implementation of RIT. The predominant complication of RIT is hematological toxicity that is usually manageable. There are ongoing trials to further define the expanding role of RIT as first line or concomitant therapy in the treatment of lymphoma as well as for certain antibiotic resistant infections and aggressive malignancies. There is also growing interest in the development of newer protocols for increased and more uniform dose delivery resulting in better outcomes and improved patient survival. This review will primarily focus on the role of RIT in treatment of non-Hodgkin's lymphoma, which is of established clinical utility and FDA approved. The mechanism of RIT, available radionuclides and pharmacokinetics, therapy administration, clinical utility and toxicities, and future directions would be discussed.     

Recommendations of the Spanish Societies of Radiation Oncology (SEOR), Nuclear Medicine & Molecular Imaging (SEMNiM), and Medical Physics (SEFM) on 18F-FDG PET-CT for radiotherapy treatment planning

Positron emission tomography (PET) with ¹⁸F-fluorodeoxyglucose (FDG) is a valuable tool for diagnosing and staging malignant lesions. The fusion of PET and computed tomography (CT) yields images that contain both metabolic and morphological information, which, taken together, have improved the diagnostic precision of PET in oncology. The main imaging modality for planning radiotherapy treatment is CT. However, PET-CT is an emerging modality for use in planning treatments because it allows for more accurate treatment volume definition. The use of PET-CT for treatment planning is highly complex, and protocols and standards for its use are still being developed. It seems probable that PET-CT will eventually replace current CT-based planning methods, but this will require a full understanding of the relevant technical aspects of PET-CT planning. The aim of the present document is to review these technical aspects and to provide recommendations for clinical use of this imaging modality in the radiotherapy planning process.     

Monoclonal antibody as therapy for malignant lymphomas

Rituximab was the first monoclonal antibody to have been registered for the treatment of B-cell lymphomas. Randomized studies have demonstrated its activity in follicular lymphoma, mantle-cell lymphoma, and diffuse large B-cell lymphoma in untreated or relapsing patients. Because of its high activity and low toxicity ratio, rituximab has transformed the outcome of patients with B-cell lymphoma. A combination of rituximab plus chemotherapy, R-CHOP, has the highest efficacy ever described with any chemotherapy in diffuse large B-cell lymphoma and follicular lymphoma. The role of radio-labelled antibodies is still to be defined.     

TEP/TDM dans le diagnostic et la stadification des lymphomes

Histological subtypes of lymphomas are important because FDG uptake is much greater in aggressive than in indolent lymphomas and this, results in lower sensitivity of PET for the staging of indolent lymphomas. Staging is especially useful when treatment is changed according to staging. Staging with imaging methods has traditionally been performed using a CT scanner and has been based on the detection of nodal enlargement, an increased number of small nodes and in the presence of extranodal masses. However, CT is limited by its poor sensitivity in the detection of extranodal sites of involvement, in the identification of tumour involvement of normal size lymph nodes and in the differentiation between malignant and inflammatory enlarged lymph nodes. The uptake of FDG detected with PET images reflects metabolic activity rather than the size of the tissue masses, localizing tumoral activity in enlarged and in normal size lymph nodes. In the literature review that compares PET with CT, PET usually indicates more lesions than CT would and PET improves sensitivity without losing specificity. However, the majority of studies report that PET, improves the staging in a relatively limited number of patients (10-20%) and may change treatment in less than 10% of patients. Diagnostic accuracy of PET may improve with the use of hybrid PET/CT systems that combine metabolic and morphological imaging, in the same scanner and without moving the patient. This is a promising technique that will overcome the limitations of both modalities and may enhance diagnostic accuracy in lymphoma patients. This hybrid equipment allows the use of PET/CT with contrast-enhanced full dose CT (a diagnostic CT) instead of carrying out PET and CT on different days.