F2-PROTOCOL: Prospective Collection of Data of Possible Prognostic Relevance in Patients With Follicular Lymphoma

So far, in patients with lymphoma a variety of studies aimed at the evaluation of prognosis have been conducted. In particular, different demographic, clinical and biological factors have shown a prognostic role in univariate and multivariate analysis, including age, gender, stage, tumor burden, bone marrow involvement, systemic symptoms, Performance status, serum lactate dehydrogenase (LDH) level, anemia, erythrocyte sedimentation rate (ESR) and beta-2 microglobulin.

The combination of those parameters has allowed the identification of several prognostic scores.

Attempts to define prognosis in follicular lymphomas begun in the late '70s. Then, when in 1993 the International Prognostic Index (IPI) was defined for aggressive lymphomas it was also applied to low-grade lymphomas leading to conflicting results, and the need for a prognostic index specifically designed for follicular lymphomas emerged.

A large study on prognosis in patients with follicular lymphoma was performed by the Italian Lymphoma Intergroup that leaded to the definition of the Italian Lymphoma Intergroup (ILI) score, based on 987 patients (Federico M et al. Blood 2000; 95(3):783-789). In 2004 the Follicular Lymphoma International Prognostic Project allowed the definition of a new score on 4167 pts with follicular lymphoma, the Follicular Lymphoma International Prognostic Index (FLIPI) (Solal-Céligny P et al. Blood 2004;104(5):1258-1265). This score is based on the evaluation of age (younger than 60 years vs 60 years or older), Ann Arbor stage (I-II vs III-IV), number of nodal sites (0-4 vs > 5 or more), Hemoglobin (Hb)level (greater than or equal 12g/dL vs lower than 12g/dL), serum Lactate Dehydrogenase (LDH) (normal vs elevated) and identifies three main groups of patients with different survival:low risk (0-1 factors); intermediate risk (2 factors); high risk (3-5 factors).

Notwithstanding the huge number of patients considered in these studies, all mentioned prognostic scores (IPI, ILI and FLIPI) are based on a retrospective analysis of archive data. This approach can introduce biases that can hamper final results. A first problem is the selection of patients that can be influenced by single institution policy and patient's or physician's related factors. Furthermore, some important variables, such as beta2-microglobulin or Erythrocyte Sedimentation Rate (ESR), that have frequently shown a high prognostic significance in univariate analysis, are hardly included in the final indexes because they are available only in a small number of patients thus loosing their value in multivariate analysis. Then, lacking homogeneous and prospectively defined criteria, retrospective evaluation of some study parameter as for example clinical response cannot be easily defined and all derived endpoints such as Failure Free Survival (FFS)or Progression Free Survival (PFS) may be biased.