Lymphomas. Multifocal Extranodal Non-Hodgkin Lymphoma: Α Clinicopathologic Study of 37 Cases in Greece, a Hellenic Cooperative Oncology Group Study

Similar documents
Large cell immunoblastic Diffuse histiocytic (DHL) Lymphoblastic lymphoma Diffuse lymphoblastic Small non cleaved cell Burkitt s Non- Burkitt s

LYMPHOMA Joginder Singh, MD Medical Oncologist, Mercy Cancer Center

PRIMARY GASTRIC LYMPHOMA: CASE REPORT WITH REVIEW OF LITERATURE

Supplementary Appendix to manuscript submitted by Trappe, R.U. et al:

During past decades, because of the lack of knowledge

Policy for Central Nervous System [CNS] Prophylaxis in Lymphoid Malignancies

Localised gastrointestinal diffuse large B cell lymphomas; Does surgical approach still exist?

Aggressive Lymphomas - Current. Dr Kevin Imrie Physician-in-Chief, Sunnybrook Health Sciences Centre

Conjunctival CD5+ MALT lymphoma and review of literatures

Clinicopathologic Profile and Outcome of Extranodal Diffuse Large B-Cell NHL: Egyptian National Cancer Institute Experience

A CASE OF PRIMARY THYROID LYMPHOMA. Prof Dr.Dilek Gogas Yavuz Marmara University School of Medicine Endocrinology and Metabolism Istanbul, Turkey

Extranodal natural killer/t-cell lymphoma with long-term survival and repeated relapses: does it indicate the presence of indolent subtype?

Aggressive NHL and Hodgkin Lymphoma. Dr. Carolyn Faught November 10, 2017

TRANSPARENCY COMMITTEE OPINION. 27 January 2010

Indolent Lymphomas: Current. Dr. Laurie Sehn

Modified Number of Extranodal Involved Sites as a Prognosticator in R-CHOP-Treated Patients with Disseminated Diffuse Large B-Cell Lymphoma

Indium-111 Zevalin Imaging

Addition of rituximab to the CHOP regimen has no benefit in patients with primary extranodal diffuse large B-cell lymphoma

Case Report Precursor B Lymphoblastic Lymphoma Involving the Stomach

Clinico-Pathological Pattern of Extranodal Non-Hodgkin s Lymphoma in Saudi Arabia

Flow cytometric evaluation of endoscopic biopsy specimens from patients with gastrointestinal tract B-cell lymphoma: a preliminary report

NON HODGKINS LYMPHOMA: AGGRESSIVE Updated June 2015 by Dr. Manna (PGY-5 Medical Oncology Resident, University of Calgary)

CLINICAL MEDICAL POLICY

Rituximab and Combination Chemotherapy in Treating Patients With Non- Hodgkin's Lymphoma

Predictive value of Follicular Lymphoma International Prognostic Index (FLIPI) in patients with follicular lymphoma at first progression

Anatomic distribution, clinical features, and survival data of 87 cases primary gastrointestinal lymphoma

Non-Hodgkin lymphomas (NHLs) Hodgkin lymphoma )HL)

Learn more about diffuse large B-cell lymphoma (DLBCL), the most common aggressive form of B-cell non-hodgkin s lymphoma 1

Patient underwent hemicolectomy: 7 x 4.5 cm intusscepted segment of ileum in colon - mucosal

Indolent Lymphomas. Dr. Melissa Toupin The Ottawa Hospital

Rituxan Hycela. Rituxan Hycela (rituximab and hyaluronidase human) Description

Analysis of clinical characteristics, diagnosis, treatment and prognosis of 46 patients with primary gastrointestinal non Hodgkin lymphoma

Panel Discussion/References

New Evidence reports on presentations given at EHA/ICML Bendamustine in the Treatment of Lymphoproliferative Disorders

Non-Hodgkin lymphoma

Update: Non-Hodgkin s Lymphoma

Strategies for the Treatment of Elderly DLBCL Patients, New Combination Therapy in NHL, and Maintenance Rituximab Therapy in FL

Rituxan Hycela (rituximab and hyaluronidase human) (Subcutaneous)

ACHIEVING EXCELLENCE IN ABSTRACTING: LYMPHOMA

A Phase II Clinical Trial of Fludarabine and Cyclophosphamide Followed by. Thalidomide for Angioimmunoblastic T-cell Lymphoma. An NCRI Clinical Trial.

Thessaloniki, Greece PLEASE SCROLL DOWN FOR ARTICLE

A retrospective analysis of clinical pathological characteristics and prognosis of 82 patients of primary intestinal lymphoma

Primary non-hodgkin Lymphomas of the Gastrointestinal Tract (GI-NHL)

Disclosures for Dr. Peter Borchmann 48 th ASH Annual meeting, Orlando, Florida

2007 ANNUAL SITE STUDY HODGKIN S LYMPHOMA

Original Article. Introduction

Pre-operative assessment of patients for cytoreduction and HIPEC

Update in Lymphoma Imaging

Clinical characteristics and outcomes of primary bone lymphoma in Korea

Sally Barrington Martin Hutchings

Corporate Medical Policy

Testicular relapse of non-hodgkin Lymphoma noted on FDG-PET

Significance of MYC/BCL2 Double Expression in Diffuse Large B-cell Lymphomas: A Single-center Observational Preliminary Study of 88 Cases

Rituximab in lymphocyte-predominant Hodgkin disease: results of a phase 2 trial

Pros and Cons: Interim PET in DLBCL Ulrich Dührsen Department of Hematology University Hospital Essen

LN04 - Lymphoma Tissue Microarray

Lymphatic system component

BACKGROUND INFORMATION ON NON-HODGKIN S LYMPHOMA

Disclosures WOJCIECH JURCZAK

Clinical characteristics, pathological distribution, and prognostic factors in non-hodgkin lymphoma of Waldeyer s ring: nationwide Korean study

ESMO DOUBLE-HIT LYMPHOMAS

Limited Role of Bone Marrow Aspiration and Biopsy in the Initial Staging Work-up of Gastric Mucosa-Associated Lymphoid Tissue Lymphoma in Korea

SWOG ONCOLOGY RESEARCH PROFESSIONAL (ORP) MANUAL RESPONSE ASSESSMENT LYMPHOMA CHAPTER 11B REVISED: SEPTEMBER 2016

두경부영역의악성림프종 태경 1 이형석 1 서인석 1 이용섭 1 조석현 1 최정혜 2 안명주 2. Hodgkin s and Non-Hodgkin s Lymphoma of Head and Neck

LEUKAEMIA and LYMPHOMA. Dr Mubarak Abdelrahman Assistant Professor Jazan University

A c as e of MA LT ly m ph om a of the thy roid ac c om p any in g H as him ot o 's thy roiditis

Instructions for Chronic Lymphocytic Leukemia Post-HSCT Data (Form 2113)

Lugano classification: Role of PET-CT in lymphoma follow-up

Understanding your diagnosis. Dr Graham Collins Consultant Haemtologist Oxford University Hospitals

Burkitt lymphoma. Sporadic Endemic in Africa associated with EBV Translocations involving MYC gene on chromosome 8

Indolent B-Cell Non-Hodgkin s Lymphomas

NON HODGKINS LYMPHOMA: INDOLENT Updated June 2015 by Dr. Manna (PGY-5 Medical Oncology Resident, University of Calgary)

2012 by American Society of Hematology

Does the omission of vincristine in patients with diffuse large B cell lymphoma affect treatment outcome?

Early-stage mantle cell lymphoma: a retrospective analysis from the International Lymphoma Radiation Oncology Group (ILROG)

CHOP CHEMOTHERAPY OF INTERMEDIATE AND HIGH-GRADE NON-HODGKIN S LYMPHOMA

Lymphoma/CLL 101: Know your Subtype. Dr. David Macdonald Hematologist, The Ottawa Hospital

High incidence of false-positive PET scans in patients with aggressive non-hodgkin s lymphoma treated with rituximab-containing regimens

Open questions in the treatment of Follicular Lymphoma. Prof. Michele Ghielmini Head Medical Oncology Dept Oncology Institute of Southern Switzerland

Survival and prognostic factors after initiation of treatment in Waldenstrom s macroglobulinemia

All India Institute of Medical Sciences, New Delhi, INDIA. Department of Pediatric Surgery, Medical Oncology, and Radiology

TRANSPARENCY COMMITTEE OPINION. 8 November 2006

Outcomes of patients with peripheral T-cell lymphoma in first complete remission: data from three tertiary Asian cancer centers

Diffuse Large B-Cell Lymphoma (DLBCL)

Head and Neck: DLBCL

Abdominal Burkitt s lymphoma in Children

Lymphoma: What You Need to Know. Richard van der Jagt MD, FRCPC

Stage IV marginal zone B-cell lymphoma prognostic factors and the role of rituximab: Consortium for Improving Survival of Lymphoma (CISL) study

Time-to-treatment of diffuse large B-cell lymphoma in São Paulo

Gastrointestinal Tract Cancer

Regression of Advanced Gastric MALT Lymphoma after the Eradication of Helicobacter pylori

Lymphocyte Predominant Hodgkin s Lymphoma. Case Presentation. How would you treat the patient?

What are the hurdles to using cell of origin in classification to treat DLBCL?

Professor Mark Bower

Overview of Cutaneous Lymphomas: Diagnosis and Staging. Lauren C. Pinter-Brown MD, FACP Health Sciences Professor of Medicine and Dermatology

Role of prophylactic radiotherapy in Chinese patients with primary testicular diffuse large B-cell lymphoma: a single retrospective study

Non-Hodgkin Lymphoma in Clinically Difficult Situations

2.07 Protocol Name: CHOP & Rituximab

Original Article Gastrointestinal malignant lymphoma: a pathologic study of 37 cases in a single Japanese institution

See Important Reminder at the end of this policy for important regulatory and legal information.

Transcription:

This material is protected by U.S. Copyright law. Unauthorized reproduction is prohibited. For reprints contact: Reprints@AlphaMedPress.com Lymphomas Multifocal Extranodal Non-Hodgkin Lymphoma: Α Clinicopathologic Study of 37 Cases in Greece, a Hellenic Cooperative Oncology Group Study Theofanis Economopoulos, a Sotirios Papageorgiou, a Dimitra Rontogianni, b Vassiliki Kaloutsi, c George Fountzilas, c Constantinos Tsatalas, d Nikolaos Pavlidis, e Dimitrios Pectasides, a Efstathios Papageorgiou, a Meletios Dimopoulos f a Second Department of Internal Medicine, Athens University, University General Hospital Attikon, Haidari, Greece; b Pathology Department, Evangelismos Hospital, Athens, Greece; c AHEPA Hospital, Aristotle University, Thessaloniki, Greece; d University Hospital, Alexandroupoli, Greece; e Medical Oncology Department, Ioannina University, Ioannina, Greece; f Department of Clinical Therapeutics, University of Athens, Athens, Greece Abstract The purpose of this retrospective study was to illustrate the clinicopathological features of patients presenting with multifocal extranodal non-hodgkin lymphoma (NHL). Among 810 patients with NHL, 37 cases (4.2%) were found to have multiple extranodal involvement (two or more sites). There were 24 men and 13 women, with a median age of 63 years. The majority of these cases (n = 26) had gastric or intestinal (GI) involvement with or without other extranodal sites. Lung along with another extranodal site was relatively common in the present series. Stratification of the 37 cases according to the International Prognostic Index (IPI) showed that 89% of the patients belonged to the high-risk groups. Diffuse large-b-cell lymphoma (DLBCL) accounted for Key Words. Lymphoma Extranodal Multifocal 62%, and mucosa-associated lymphoma tissue (MALT) lymphoma accounted for 27% of all cases. After induction treatment with anthracycline-based regimens, complete remission was achieved in 21 patients (57%), partial remission was achieved in six patients (16%), and seven patients (19%) had no response, while three patients (8%) were nonevaluable. In conclusion, multifocal extranodal NHL is a heterogeneous group of diseases. The majority of them arise at various sites in the GI tract. DLBCL was the most frequent histological subtype followed by MALT lymphoma. Risk group, as defined by the IPI, was predictive of survival. The Oncologist 2005;10:734 738 Introduction The involvement of extranodal sites is a common feature during the course of non-hodgkin lymphomas (NHLs). Moreover, some NHLs are considered to originate at sites other than the lymph nodes or spleen and are referred to as primary extranodal lymphoma (PE-NHL) [1, 2]. The origin of most PE-NHLs can be ascribed to one given organ system or site. However, there exists a heterogeneous collection of NHLs that may involve multiple sites throughout the body at presentation. This group of NHL includes Burkitt s lymphoma, angiotropic (intravascular) large-cell lymphoma, and angiocentric lymphoma [3]. In addition to the above subtypes of Correspondence: T. Economopoulos, University General Hospital Attikon, 1 Rimini Str., 124 62 Haidari, Greece. Telephone: 30-210- 5831255; Fax: 30-210-5326450; e-mail: sotirispapageorgiou@hotmail.com Received August 2, 2005; accepted for publication August 10, 2005. AlphaMed Press 1083-7159/2005/$12.00/0 The Oncologist 2005;10:734 738 www.theoncologist.com

Economopoulos, Papageorgiou, Rontogianni et al. 735 NHL, there is a group of lymphomas that includes patients whose disease is diagnosed simultaneously at several extranodal sites. Although most of these cases are localized to the gastrointestinal (GI) tract [4, 5, 6], they also involve a variety of extranodal sites outside the GI tract. To assess the incidence, disease features, and outcome of patients presenting with multifocal extranodal lymphomas, we performed a retrospective analysis of the Hellenic Cooperative Oncology Group (HeCOG) lymphoma registry. Materials and Methods Between May 1994 and December 2002, 810 patients with NHL were diagnosed and treated in different centers of the HeCOG. Among these, 37 patients (4.2%) were found to have multiple extranodal involvement (two or more sites) at presentation. Patients with concomitant involvement of lymph nodes, spleen, or bone marrow were not included. All patients were classified according to the World Health Organization classification [7]. The original histological slides of the 37 patients with multifocal involvement were reviewed by two expert hematopathologists (D.R., V.K.). Patients with Burkitt s lymphoma were excluded from the study. Patients were staged according to the Ann-Arbor classification [8] with its modification by Musshoff [9] for GI tract lymphomas. Staging was performed by physical examination; surgical reports; complete blood count; computed tomography scan of the thorax, abdomen, and pelvis; biochemical profile; and bone marrow biopsy. When indicated, a bone scan, biopsies of suspicious lesions, and examination of the cerebrospinal fluid were also performed. All patients with GI involvement underwent endoscopy. Most presenting symptoms were caused by the extranodal involvement, and extranodal presentation remained the clinically dominant site of disease. Of 37 patients, 28 received chemotherapy alone, whereas nine underwent surgery, which was followed by chemotherapy in eight of them. Surgery consisted of subtotal gastrectomy in five cases, small intestine resection in two cases, colectomy in one case, and thyroidectomy in one case. As far as chemotherapy is concerned, 30 patients received an anthracycline-based regimen, CHOP/CEOP/ CNOP (cyclophosphamide, doxorubicin [Adriamycin ; Bedford Laboratories, Bedford, OH, http://www.bedfordlabs.com]/epirubicin [Ellence ; Pfizer Pharmaceuticals, New York, http://www.pfizer.com]/mitoxantrone [Novantrone ; Serono, Inc., Rockland, MA, http://www.seronousa.com], vincristine [Oncovin ; Eli Lilly and Company, Indianapolis, http://www.lilly.com], prednisone [Deltasone ; Pfizer Pharmaceuticals]); three patients received a combination of fludarabine (Fludara ; Berlex Laboratories, Wayne, NJ, http://www.berlex.com) and mitoxantrone; three patients received a combination of CEOP with the monoclonal antibody rituximab (Rituxan ; Genentech, Inc., South San Francisco, CA, http://www.gene.com); and one patient refused further treatment after surgery. Response after treatment was assessed according to the report of the international workshop to standardize response criteria for NHL [10]. Complete response (CR) required the complete disappearance of all detectable clinical and radiological evidence of disease, disappearance of all disease-related symptoms, and normalization of those biochemical abnormalities definitely assignable to the lymphoma. Partial response (PR) required at least a 50% decrease in the sum of the products of the greatest diameters of the involved extranodal site. Any lesser response was considered as a nonresponse (NR). Overall survival was estimated from the date of first biopsy to the date of last follow-up or until the patient s death. Time to disease progression (TTP) was calculated from the date of the first biopsy to the date of the first progression of the disease. However, the deaths of patients who died because of disease-related factors without having previous documentation of disease progression were considered as events in the estimation of TTP. The Kaplan-Meier method [11] was used to calculate TTP, median follow-up, and survival curves, while the logrank test was used to compare time-to-event distributions. Exact binomial confidence intervals were used to determine the 95% upper and lower confidence limits of the response rate [12]. Results Clinical and Laboratory Findings The clinical and laboratory findings of all patients are listed in Table 1. There were 24 men and 13 women, with a median age of 63 years (range, 19 82). Lymphomas originating from more than one extranodal site do not fit into the Ann-Arbor classification or its modification by Musshoff [9] for GI lymphomas, other than stage IVE. Therefore, all our patients were considered as stage IV. The stratification of the 37 cases according to the International Prognostic Index (IPI) [13] showed that the vast majority of the patients (89%) was in the high-risk groups. Sites of Involvement and Histology The specific extranodal sites of involvement and the corresponding histological subtypes are shown in Table 2. Simultaneous involvement of gastric and other extranodal sites was observed in 26 patients. The histological distribution of these cases was: diffuse large-b-cell lymphoma (DLBCL), 16 cases; MALT lymphoma, 8 cases; mantle cell lymphoma, 2 cases.

736 Multifocal Extranodal Non-Hodgkin Lymphoma Table 1. Multifocal lymphomas clinical and laboratory findings No. % Gender Male Female Age Median Range B symptoms No Yes 24 13 63 19 82 19 65 35 49 51 Stage IV 37 100 Lactate dehydrogenase Normal Abnormal International Prognostic Index Score Low intermediate High Intermediate High risk 20 17 4 51 43 11 49 40 Table 2. Multifocal lymphomas extranodal sites and histology The remaining 11 patients presented with two or more extranodal sites other than the GI tract. Bone and lung were affected most commonly. Seven of the above cases had DLBCL, two had MALT NHL, one had angiocentric T-cell NHL, and one had lymphoplasmacytoid lymphoma (Table 2). Response to Treatment and Survival Thirty-four patients were evaluable for response. Three patients could not be evaluated for the following reasons: patient s refusal of therapy (n = 1) and lost to follow-up (n = 2). After induction treatment, CRs were achieved in 21 patients (57%), PRs were achieved in 6 patients (16%), and 7 patients (19%) were NR. The median overall survival duration for all patients was 71.8 months (range, 3.8 132.1), and the median TTP was 25.9 months (range, 2.7 132.1) (Fig. 1). The median survival and TTP according to IPI risk group were as follows: low-intermediate risk, median sur- Histology Extranodal site No. of patients DLBCL MALT Mantle LPL AGTCL Gastric, small intestine 8 6 2 - - - Gastric, large bowel 7 3 2 2 - - Gastric, small intestine, large bowel 1 1 - - - - Gastric, small intestine, lung 1 1 - - - - Gastric, small intestine, liver 1 1 - - - - Gastric, lung 3 1 2 - - - Gastric, lung, liver 1 1 - - - - Gastric, nasopharynx 1-1 - - - Gastric, ovary 1 1 - - - - Large bowel, liver 1 1 - - - - Small intestine, lung, pancreas 1-1 - - - Bone multifocal 1 1 - - - - Bone, lung 2 2 - - - - Bone, skin 1 1 - - - - Lung, kidney 1 1 - - - - Lung, skin, bone marrow 1 - - - - 1 Thyroid, liver 1-1 - - - Nasopharynx, abdominal mass 1 1 - - - - Larynx, liver 1 - - - 1 - Mouth, nasal cavity 1-1 - - - Testis, nasopharynx, skin 1 1 - - - - Total 37 23 10 2 1 1 Abbreviations: AGTCL, angiocentric lymphoma; DLBCL, diffuse large-b-cell lymphoma; LPL, lymphoplasmacytoid lymphoma; MALT, mucosa-associated lymphoma tissue.

Economopoulos, Papageorgiou, Rontogianni et al. 737 vival and TTP not reached yet (range, 14.2 114 months and 8.3 114 months, respectively); high -intermediate risk, median survival not reached yet (range, 3.8 132.1 months), median TTP 28.2 months (range, 3.8 132.1); high risk, median survival 32.4 months (range, 4.9 80.8), median TTP 17.8 months (range, 2.7 80.8). These differences were not statistically significant. Two patients developed a second malignancy. One patient with initial involvement of the testis, nasopharynx, and skin, with diffuse large-cell histology, developed esophageal cancer. Another patient with thyroid involvement and an abdominal mass, with MALT histology, developed colon cancer. Discussion NHL constitutes a group of disorders originating from the malignant transformation of lymphocytes and involving either the lymph nodes or extranodal sites. Extranodal lymphomas may comprise 24% 48% of NHL cases, and there appears to be an increasing incidence of these lymphomas during the past decades [1]. Extranodal lymphomas may occur in any organ. They present most frequently in the GI tract, followed by Waldeyer s ring, when tonsils are regarded as an extranodal site. Other common sites are skin and bone. Less common primary localizations of PE- NHL have also been reported [1, 2, 14]. Although there are reports on PE-NHL of various sites, especially GI-NHL, there remain many questions concerning the clinicopathological features and treatment outcome of these patients. These factors are well known for Burkitt s, angiotropic, and angiocentric lymphomas [3], but the subject of the multifocal extranodal appearance of the various Figure 1. Overall survival (solid line) and time to progression (dashed line) for all patients. histological subtypes is not well studied. The incidence of such cases is poorly defined, apart from GI multifocal lymphomas, which comprise 4% 7% [4, 6, 15]. Our study included 37 patients with primary lymphoma involving multiple extranodal sites at presentation. Among 810 patients diagnosed and treated in our centers, the incidence of multifocal extranodal disease was 4.2%. The majority of these cases (n = 26) had gastric or intestinal involvement with or without other extranodal sites. Lung along with another extranodal site was relatively common in the present series. The remaining multifocal cases were patients with head and neck lymphoma, bone lymphoma, and testicular lymphoma. In our series of multifocal extranodal lymphoma, DLBCL was the most frequent histological subtype, comprising 62% of cases. Next in frequency were low-grade MALT lymphomas (27%). These findings are in agreement with those reported in a large series of GI lymphomas with multiple sites of involvement [6]. However, in another series [4], low-grade MALT lymphoma was the most frequent histological subtype among cases with multiple GI involvement. The reason for multifocal extranodal lymphomas or the preferential involvement of specific extranodal sites at recurrence is not clear, but it is likely that this is closely linked to the homing process regulated by homing receptors or lymphoid cells and ligands on high endothelial venules [16]. This tropism for specific sites has been particularly noticeable for the tonsils and stomach [17, ], testis and nasopharynx, and skin and bone [16, 19]. The vast majority of the lymphomas in our study were of B-cell origin, in particular DLBCL from cells at the germinal-center or postgerminal-center stage of development. One explanation for the high frequency of B-cell lymphomas might be the fact that the B cells undergo clonal expansion during proliferation in the microenvironment of the germinal centers. It appears that B-cell lymphomas often need stimulation that involves the antigen receptor or other receptors on the surface of the lymphoma cells. It could be that the stimulus is the same in the different sites of origin of B-cell lymphomas. The genetic events that take place in germinal cells and give rise to B-cell lymphoma do not exist during the development of T-cell lymphocytes. This could be the reason for the fact that the T cells give rise to lymphomas one tenth to one twentieth as often as B cells [20]. Since our study is retrospective, conclusions about treatment efficacy should be made with caution. It is noteworthy, however, that all patients were treated with anthracyclinebased regimens, and that low-risk patients had excellent treatment responses. For patients in the high-risk group, the prognosis was less favorable.

738 Multifocal Extranodal Non-Hodgkin Lymphoma In summary, our results indicate that lymphomas that are multifocal at presentation are a heterogeneous group of diseases. The majority of them arise at various sites in the GI tract, while a considerable number of cases include lung involvement along with other extranodal sites. Histologically aggressive NHL accounted for the majority of cases, and risk group, as defined by the IPI, was predictive of survival. Disclosure of Potential Conflicts of Interest The authors indicate no potential conflicts of interest. References 1 d Amore F, Christensen BE, Brincker H et al. Clinicopathological features and prognostic factors in extranodal non-hodgkin lymphomas. Danish LYFO Study Group. Eur J Cancer 1991;27:1201 1208. 2 Economopoulos T, Asprou N, Stathakis N et al. Primary extranodal non- Hodgkin s lymphoma in adults: clinicopathological and survival characteristics. Leuk Lymphoma 1996;21:131 136. 3 Isaacson PG, Norton AJ. Multifocal extranodal lymphoma. In: Isaacson PG, Norton AJ, eds. Extranodal Lymphomas. Edinburgh, Scotland: Churchill Livingstone, 1994:315 329. 4 Koch P, del Valle F, Berdel WE et al. Primary gastrointestinal non- Hodgkin s lymphoma: I. Anatomic and histologic distribution, clinical features, and survival data of 371 patients registered in the German Multicenter Study GIT NHL 01/92. J Clin Oncol 2001;19:3861 3873. 5 Thieblemont C, Bastion V, Berger F et al. Mucosa-associated lymphoid tissue gastrointestinal and nongastrointestinal lymphoma behavior: analysis of 108 patients. J Clin Oncol 1997;15:1624 1630. 6 d Amore F, Brincker H, Gronbaek K et al. Non-Hodgkin s lymphoma of the gastrointestinal tract: a population-based analysis of incidence, geographic distribution, clinicopathologic presentation features, and prognosis. Danish Lymphoma Study Group. J Clin Oncol 1994;12:1673 1684. 7 Harris NL, Jaffe ES, Diebold J et al. World Health Organization classification of neoplastic disease of the hematopoietic and lymphoid tissues: report of the clinical advisory meeting Airlie House, Virginia, November 1997. J Clin Oncol 1999;17:3835 3849. 8 Carbone PP, Kaplan HS, Musshoff K et al. Report of the Committee on Hodgkin s Disease Staging Classification. Cancer Res 1971;31:60 61. 9 Musshoff K. Clinical staging classification of non-hodgkin s lymphomas. Strahlentherapie 1977;153:2 221. 10 Cheson BD, Horning SJ, Coiffier B et al. Report of an international workshop to standardize response criteria for non-hodgkin s lymphomas. NCI Sponsored International Working Group. J Clin Oncol 1999;17: 1244 1253. 11 Kaplan E, Meier P. Non parametric estimation from incomplete observations. J Am Stat Assoc 1958;53:457 481. 12 Lenter C. Geigy Scientific Tables (Exact Confidence Limits for p). Ciba- Geigy Switzerland, 1982:89 102. 13 A predictive model for aggressive non-hodgkin s lymphoma. The international Non-Hodgkin s Lymphoma Prognostic Factors Project. N Engl J Med 1993;329:987 994. 14 Otter R, Gerrits WBJ, Sandt MMVD et al. Primary extranodal and nodal non-hodgkin s lymphoma. Eur J Clin Oncol 1989;25:1203 1210. 15 Hansen PB, Vogt KC, Skov RL et al. Primary gastrointestinal non-hodgkin s lymphoma in adults: a population-based clinical and histopathologic study. J Intern Med 1998;244:71 78. 16 Advani SH, Iyer RS, Gopal R et al. Multifocal extranodal lymphomas: an expression of homing phenomenon. Oncology 1990;47:334 338. 17 Economopoulos T, Asprou N, Stathakis N et al. Primary extranodal non- Hodgkin s lymphoma of the head and neck. Oncology 1992;49:484 488. Yuen A, Jacobs C. Lymphomas of the head and neck. Semin Oncol 1999;26:338 345. 19 Shahab N, Doll DC. Testicular lymphoma. Semin Oncol 1999;26: 259 269. 20 Kuppers R, Klein U, Hansmann ML et al. Cellular origin of human B-cell lymphomas. N Engl J Med 1999;341:1520 1529.