Prognosis of follicular lymphomas

Prognostic Factors in Follicular Lymphoma: The Importance of beta-2 Microglobulin

Aims and background

The Follicular Lymphoma International Prognostic Index (FLIPI) is a useful tool for the prognostic assessment of follicular lymphoma but beta-2 microglobulin (B2M) was not incorporated in this index. We aimed to compare the predictive value of B2M, FLIPI and other prognostic factors not included in the FLIPI index for overall survival (OS), complete remission (CR), and time to treatment failure (TTF) in a nonselected follicular lymphoma series.

Methods and study design

Retrospective univariate and multivariate analysis of the prognostic value (for OS, CR, TTF) of B2M, FLIPI and other prognostic variables in follicular lymphoma was conducted in a cohort of follicular lymphoma patients between 1987 and 2007.

Results

One hundred and six patients were studied. In univariate analysis B2M and B symptoms were significantly associated with OS, and FLIPI only detected two risk levels. In multivariate analysis of OS only two significant variables were found: FLIPI and B2M. Multivariate analysis of CR showed that normal B2M, absence of a bulky mass, uninvolved bone marrow, and chemotherapy with rituximab were significant predictors of CR. FLIPI (three levels), B2M, bone marrow infiltration, and chemotherapy with rituximab were significantly associated with TTF.

Conclusions

We found a high predictive value of B2M for OS, CR, and TTF. B2M and FLIPI were the most important variables to predict OS. However, in our series FLIPI differentiated only between two mortality risk levels.

Elevated serum levels of IL-2R, IL-1RA, and CXCL9 are associated with a poor prognosis in follicular lymphoma

Serum cytokines and chemokines may reflect tumor biology and host response in follicular lymphoma (FL). To determine whether the addition of these biological factors may further refine prognostication, 30 cytokines and chemokines were measured in pretreatment serum specimens from newly diagnosed FL patients (n = 209) and from 400 matched controls. Cytokine levels were correlated with clinical outcome in patients who were observed or received single agent rituximab, or those who received chemotherapy. Correlations with outcome in chemotherapy treated patients were further examined in a separate cohort of 183 South West Oncology Group (SWOG) patients and all patients were then included in a meta-analysis. Six cytokines were associated with outcome in the Molecular Epidemiology Resource (MER) after adjusting for the FL international prognostic index. In patients who were observed or treated with rituximab alone, increased serum IL-12 and interleukin 1 receptor antagonist (IL-1RA) (P = .005 and .02) were associated with a shorter event-free survival. In patients receiving chemotherapy, hepatocyte growth factor, IL-8, IL-1RA, and CXCL9 (P = .015, .048, .004, and .0005) predicted a shorter EFS. When the MER chemotherapy treated patients and SWOG patients were combined in a meta-analysis, IL-2R, IL-1RA, and CXCL9 (P = .013, .042, and .0012) were associated with a poor EFS.

Prognostic assessment in patients with indolent B-cell lymphomas

Follicular lymphoma (FL) is an indolent lymphoma with long median survival. Many studies have been performed to build up prognostic scores potentially useful to identify patients with poorer outcome. In 2004, an international consortium coordinated by the International Follicular Lymphoma Prognostic Factor project was established and a new prognostic study was launched (FLIPI2) using progression-free survival (PFS) as main endpoint and integrating all the modern parameters prospectively collected. Low-grade non-Hodgkin lymphomas were once considered as a heterogenous group of lymphomas characterized by an indolent clinical course. Each entity is characterized by unique clinicobiologic features. Some studies have been focused on prognostic factors in single lymphoma subtypes, with the development of specific-entity scores based on retrospective series, for instance splenic marginal zone lymphoma (SMZL). A widely accepted prognostic tool for clinical usage for indolent non-follicular B-cell lymphomas is largely awaited. In this paper we summarized the current evidence regarding prognostic assessment of indolent follicular and non-follicular lymphomas.

Prognostic tools in follicular lymphomas

Despite significant improvements in treatment modalities over the 10 years, the clinical course of patients with follicular lymphoma (FL) remains heterogeneous. Thus, prognostic indexes are still required to direct treatment choices and for the design of clinical trials. Investigators have conducted a variety of studies aimed at integrated assessment of biological and clinical features in order to identify novel prognostic factors and scoring systems. Genetic studies focused on tumor cells and the tumor microenvironment represent a step forward in understanding the biology of FL and are likely to provide new prognostic tools for future clinical use. Several prognostic factors have been identified and are currently used in combination to establish prognostic scores and to support therapeutic decisions. The FL International Prognostic Index (FLIPI) is currently used for defining individual risk of death. More recently, FLIPI2 was developed by the same group that built FLIPI as a new model for prognostic definition of patients with FL. The model was defined using prospectively collected data from patients who also received the monoclonal therapeutic antibody rituximab and stratifies patients into three risk categories for disease progression. Since many biological factors are not yet clinically validated or easily assessable, clinical data still represent the major source of prognostic information. The progressive development of new and more effective therapies for the treatment of FL makes the study of prognosis a dynamic and evolving area of clinical research.

Predicting outcome in follicular lymphoma by using interactive gene pairs

PURPOSE

Follicular lymphoma is a common lymphoma of adults. Although its course is often indolent, a substantial proportion of patients have a poor prognosis, often due to rapid progression or transformation to a more aggressive lymphoma. Currently available clinical prognostic scores, such as the follicular lymphoma international prognostic index, are not able to optimally predict transformation or poor outcome.

EXPERIMENTAL DESIGN

Gene expression profiling was done on primary lymphoma biopsy samples.

RESULTS

Using a statistically conservative approach, predictive interaction analysis, we have identified pairs of interacting genes that predict poor outcome, measured as death within 5 years of diagnosis. The best gene pair performs >1,000-fold better than any single gene or the follicular lymphoma international prognostic index in our data set. Many gene pairs achieve outcome prediction accuracies exceeding 85% in extensive cross-validation and noise sensitivity computational analyses. Many genes repeatedly appear in top-ranking pairs, suggesting that they reproducibly provide predictive capability.

CONCLUSIONS

The evidence reported here may provide the basis for an expression-based, multi-gene test for predicting poor follicular lymphoma outcomes.

Hematological Oncology: further ahead

This editorial presents the new editorial structure of Hematological Oncology and summarizes the topics of interest of the journal. Authors are strongly encouraged to submit quality manuscripts regarding all the aspects of haematologic cancers via the Hematological Oncology website at http://mc.manuscriptcentral.com/hon.