Prognostic relevance of serum beta2 microglobulin in patients with follicular lymphoma treated with anthracycline-containing regimens. A GISL study.

Background and ObjectivesAlthough serum b2 microglobulin (b2M) is an easy parameter to measure, and overexpressedin a large number of lymphoproliferative diseases, its prognostic value hasbeen largely underestimated. The present study examined the influence of b2M levelson overall survival (OS) of patients with follicular lymphoma (FL).Design and MethodsThe prognostic role of b2M was evaluated in 236 patients with FL identified from thedatabases of the Gruppo Italiano per lo Studio dei Linfomi (GISL) and treated withanthracycline-based regimens from 1993 to 2003.ResultsElevated serum b2M levels were found in 82 patients (35%). According to multivariatelogistic regression analysis, elevated b2M levels were associated with elevatedlactate dehydrogenase (LDH) (p=0.021), age (p=0.029), and number of involvednodal areas (p<0.001). The percentage of elevated b2M levels increased progressivelywith increasing FLIPI scores (17%, 38%, and 63% in the low-, intermediate-, andhigh-risk groups, respectively). Five-year OS was 61% (95% CI, 47-73%) and 89% (95%CI, 82-93%) for patients with elevated vs normal b2M levels respectively (p<0.001).Cox regression analysis showed that b2M level had an independent and stable prognosticvalue (HR=3.0; 95%CI, 1.6-5.7). In a multivariate analysis the impact of b2Mlevel on survival was independent of FLIPI score, with a HR of 2.94 (95% CI, 1.54-5.62).Interpretation and ConclusionsOur results demonstrate that in patients treated in the pre-rituximab era, b2M levelwas an independent prognostic marker in addition to FLIPI score. We thus suggestthat b2M be routinely assessed and tested in future prognostic studies of FL patientstreated with combination chemotherapy and anti-CD20 agents.