Routine use of ancillary investigations in staging diffuse large B-cell lymphoma improves the International Prognostic Index (IPI)

BACKGROUND

The International Prognostic Index (IPI) is used to determine prognosis in diffuse large B-cell lymphoma (DLBCL). One of the determinants of IPI is the stage of disease with bone marrow involvement being classified as stage IV. For the IPI, involvement on bone marrow is traditionally defined on the basis of histology with ancillary investigations used only in difficult cases to aid histological diagnosis. This study aimed to determine the effect of the routine use of flow cytometry, immunohistochemistry and molecular studies in bone marrow staging upon the IPI.

RESULTS

Bone marrow trephines of 156 histologically proven DLBCL cases at initial diagnosis were assessed on routine histology, and immunohistochemistry using two T-cell markers (CD45RO and CD3), two B-cell markers (CD20 and CD79a) and kappa and lambda light chains. Raw flow cytometry data on all samples were reanalysed and reinterpreted blindly. DNA extracted from archived paraffin-embedded trephine biopsy samples was used for immunoglobulin heavy chain and light chain gene rearrangement analysis. Using immunophenotyping (flow cytometry and immunohistochemistry), 30 (19.2%) cases were upstaged to stage IV. A further 8 (5.1%) cases were upstaged using molecular studies. A change in IPI was noted in 18 cases (11.5%) on immunophenotyping alone, and 22 (14.1%) cases on immunophenotyping and molecular testing. Comparison of two revised IPI models, 1) using immunophenotyping alone, and 2) using immunophenotyping with molecular studies, was performed with baseline IPI using a Cox regression model. It showed that the revised IPI model using immunophenotyping provides the best differentiation between the IPI categories.

CONCLUSION

Improved bone marrow staging using flow cytometry and immunohistochemistry improves the predictive value of the IPI in patients with DLBCL and should be performed routinely in all cases.

Primary central nervous system lymphoma

Primary central nervous system lymphomas (PCNSL) are aggressive malignancies that arise in distinct anatomical sites, which display unique structural, biological and immunological conditions. So far, despite recent therapeutic advances, these malignancies exhibit one of the worst prognoses among all non-Hodgkin lymphomas (NHL). For a long time, radiotherapy (RT) has been the standard treatment, producing a response rate of 60-65% and a notable neurological improvement in most cases. However, relapse usually occurred within a few months after RT, with a median survival of 14 months and a 5-year survival of approximately 15-24%. Although the introduction of systemic chemotherapy has consistently improved survival, the prognosis of PCNSL is still dismal, with high rates of local relapse and consequent death. Defining the optimum therapeutic management is difficult because of potential selection biases in large retrospective reviews and the limited number of prospective studies. Although studies published on PCNSL are increasing, several therapeutic questions still remain unanswered after a decade of research.

Clinical utility and pharmacology of high-dose methotrexate in the treatment of primary CNS lymphoma

Primary CNS non-Hodgkin lymphoma (PCNSL) has been shown to be increasing in incidence. This appears to be a consequence of the increasing population of those older than 65 years of age in whom PCNSL occurs most often. PCNSL often has a favorable response to treatment and aggressive management may result in extended survival and, in a proportion of patients less than 65 years of age, cure. The majority of neuro-oncologist's advocate utilizing high-dose methotrexate (HD-MTX) as a platform for the chemotherapy treatment of these neoplasms. In this review, the literature regarding HDHMTX as a treatment for PCNSL is summarized as are the pharmacological principles of HD-MTX.

Summary statement on primary central nervous system lymphomas from the Eighth International Conference on Malignant Lymphoma, Lugano, Switzerland, June 12 to 15, 2002

Under the sponsorship of the International Extranodal Lymphoma Study Group, a Multidisciplinary Workshop on primary CNS lymphoma (PCNSL) with over 50 participants from Europe, North America, Israel, and Australia was held as part of the Eighth International Conference on Malignant Lymphoma in Lugano, Switzerland (June 12 to 15, 2002). The main purposes of the Workshop were to exchange the latest scientific information, to analyze methodologic issues in the design of clinical trials, to reach a consensus on treatment recommendations and prognostic factors, to discuss clinical and molecular targets for future studies, and to establish an international collaborative group to conduct laboratory and clinical investigations in PCNSL. This article summarizes the contents of the Workshop, analyzes the current knowledge on the most relevant biologic and clinical issues in PCNSL, and focuses on fundamental challenges to be addressed in future studies.

Therapeutic management of primary central nervous system lymphoma: lessons from prospective trials

Primary central nervous system lymphomas (PCNSL) are aggressive malignancies, exhibiting one of the worst prognoses among lymphomas. The best treatment modality for PCNSL has not yet been identified. Several therapeutic questions still remain unanswered, and some methodological pitfalls in clinical trials prevent definitive conclusions from being drawn. In this review, certain aspects of trial design as well as emerging therapeutic guidelines are analyzed, and future perspectives are discussed. In the vast majority of prospective trials, general criteria for treatment of aggressive lymphomas were adopted, choosing primary chemotherapy (CHT) followed by radiotherapy (RT) as therapeutic modality. This strategy produced a five-year survival of 22%- 40% in comparison to the 3%-26% reported with RT alone. Systemic high-dose methotrexate (HD-MTX) seems to be the most effective drug, producing a response rate of 80%-90% and a two-year survival of 60%-65%. To date, the addition of other drugs at conventional doses have not consistently improved outcome. With a few exceptions, any regimen without HD-MTX comprehensively performed no better than RT alone. In combined treatment. RT doses should be decided on the bases of response to primary CHT and the number of lesions, and, until definitive conclusions from well-designed trials are available, RT parameters should follow the widely accepted principles used for other aggressive lymphomas. CHT as exclusive treatment, keeping RT for relapses or persistent disease, appears to be an attractive strategy. However, the worldwide experience with this modality is still limited, and corroborating data are needed. Intrathecal CHT still has not found a defined role in PCNSL management. Preliminary data seem to indicate that adequate meningeal treatment with HD-MTX, but without intrathecal CHT, could also be suitable in positive-cerebrospinal fluid patients. Future efforts should be addressed to identify new active drugs and more efficient CHT combinations, to evaluate the efficacy of high-dose CHT supported by autologous peripheral blood stem cells transplantation, and to clarify the impact of RT delay in complete responders, the usefulness of intrathecal CHT, and the best management for elderly patients. The assessment of impact of treatment on neuropsychological functions and quality of life is a mandatory endpoint in clinical trials.

Phase II multicenter study of brief single-agent methotrexate followed by irradiation in primary CNS lymphoma

PURPOSE

To assess, in a multi-institutional setting, the impact on relapse, survival, and toxicity of adding two cycles of intravenous methotrexate to cranial irradiation for immunocompetent patients with primary CNS lymphoma.

PATIENTS AND METHODS

Forty-six patients with a median age of 58 years and Eastern Cooperative Oncology Group performance status 0 to 3 were entered onto this phase II study. The protocol consisted of methotrexate 1 g/m(2) on days 1 and 8 followed by cranial irradiation on day 15. A whole-brain dose of 45 Gy was followed by a boost of 5.4 Gy. Intrathecal chemotherapy and spinal irradiation were given only to patients for whom cytologic examination of CSF was positive for CNS lymphoma. The median follow-up time was 36 months, with a minimum potential follow-up of 12 months.

RESULTS

Median survival was 33 months, with 2-year probability of survival 62% +/- 15% (95% confidence interval). Twenty patients have relapsed. The predominant site of relapse was the brain. Neither performance status nor age was found to influence survival. Six patients developed a dementing illness at a median of 16 months after treatment, and three of these died as a consequence.

CONCLUSION

A brief course of intravenous methotrexate before cranial irradiation is associated with 2-year and median survival rates superior to those reported for radiotherapy alone and similar to more intensive combined-modality regimens. Neurotoxicity remains an important competing risk for these patients.

Chromosomal imbalances in primary lymphomas of the central nervous system

Twenty-two primary central nervous system lymphomas of immunocompetent adults were studied by comparative genomic hybridization. All were high-grade diffuse large B cell lymphomas. Comparative genomic hybridization revealed an average of 5.5 chromosomal changes per tumor, with gains being more common than losses (3.5 vs. 2.0). The most frequent DNA copy number changes were gains on chromosomes 1, 12, 18 (41% each), 7 (23%), and 11 (18%) and losses involving chromosomes 6 (59%), 18, and 20 (18% each). Commonly involved regions were +12q (41%), +18q (36%), +1q (32%), and +7q (23%), as well as -6q (50%), -6p (18%), -17p, and -18p (14% each). High-level gains were found on 7 chromosomes, mainly involving chromosomes 18q (23%), 12q (18%), and 1q (14%). Minimal common regions of over- and underrepresentation were found on +1q25-31, -6q16-21, +7q11.2, +12p11.2-13, +12q12-14, +12q22-24.1, and +18q12.2-21.3. A significant correlation between loss of DNA copy numbers on chromosome 6q and shorter survival could be established (10.2 vs. 22.3 months; P < 0.05). Our findings suggest that chromosomal imbalances of primary central nervous system lymphomas are similar to those of diffuse large B cell lymphomas at other locations and are probably not related to cerebral presentation; however, they may be prognostically relevant.