Applicability of the International Index for aggressive lymphomas to patients with low-grade lymphoma

Variables used to build up the International Index for aggressive lymphomas (age, performance status, stage, extranodal involvement, and lactic dehydrogenase [LDH]) are also important in low-grade lymphoma. To assess the prognostic value of this index in low-grade lymphoma, we have applied it to a series of 125 patients.

One hundred twenty-five patients with low-grade lymphoma who were diagnosed at a single institution over a 20-year period and treated with standard chemotherapy were studied. End points of the study were response to therapy and survival according to the International Index. In addition to the International Index, main initial and evolutive variables were evaluated. Univariate and multivariate methods were used.

After applying the International Index, the patients divided into four risk groups: low (36% of cases), low-intermediate (32%), high-intermediate (20.8%), and high (11.2%), with complete response (CR) rates in the four groups being 60%, 35%, 23%, and 21%, respectively. Ten-year overall survival rates for the risk groups were as follows: low, 73.6%; low-intermediate, 45.2%; high-intermediate, 53.5%; and high, 0% (P < .001). When the International Index was included in a multivariate analysis, along with the main initial variables, International Index (P < .001) and sex (male, worse) (P = .038) were the only parameters related to survival. When response to therapy was also included, achievement of CR (P < .0001) and International Index (P < .001) were the most important factors. In patients who achieved a CR, the International Index was the only parameter related to survival (P = .051). The results were the same when the International Index was applied to the subset of 107 patients with follicular lymphoma.

In this study, the International Index has been found to be an important prognostic tool in low-grade lymphomas. Such an index could be used to predict prognosis not only in aggressive, but also in low-grade lymphomas.