Secondary infiltration of the central nervous system in patients with diffuse large B-cell lymphoma.

Objective: To investigate the incidence and risk factors of infiltration of the central nervous system after the initial treatment of diffuse large B-cell lymphoma in patients treated at Santa Casa de Misericórdia de São Paulo.

Methods: A total of 133 patients treated for diffuse large B-cell lymphoma from January 2001 to April 2008 were retrospectively analyzed in respect to the incidence and risk factors of secondary central nervous system involvement of lymphoma. Intrathecal prophylaxis was not a standard procedure for patients considered to be at risk. This analysis includes patients whether they received rituximab as first-line treatment or not.

Results: Nine of 133 (6.7%) patients developed central nervous system disease after a mean observation time of 29 months. The median time to relapse or progression was 7.9 months after diagnosis and all but one patient died despite the treatment administered. Twenty-six (19.5%) patients of this cohort received rituximab as first-line treatment and nine (7.1%) received intrathecal chemoprophylaxis. Of the nine patients that relapsed, seven (77.7%) had parenchymal central nervous system involvement; seven (77.7%) had stage III or IV disease; one (11.1%) had bone marrow involvement; two (22.2%) had received intrathecal chemoprophylaxis; and 3 (33.3%) had taken rituximab. In a multivariate analysis, the risk factors for this infiltration were being male, previous use of intrathecal chemotherapy and patients that were refractory to initial treatment.

Conclusion: Central nervous system infiltration in this cohort is similar to that of previous reports in the literature. As this was a small cohort with a rare event, only three risk factors were important for this infiltration.