Should rituximab replace splenectomy in the management of splenic marginal zone lymphoma?

BACKGROUND: SMZL is a relatively rare low grade B-cell lymphoma, characterized usually by an indolent clinical behavior. Since there is no prospective randomized trials to establish the best treatment approach, decision on therapeutic management should be based on the available retrospective series. Based on these data, rituximab and splenectomy appear to be the most effective. Splenectomy represented the standard treatment modality until early 2000s. More than 90% of the patients present quick amelioration of splenomegaly related symptoms along with improvement of cytopenias related to hypersplenism. The median progression free survival was 8.25 years in the largest series of patients published so far, while the median 5- and 10- year OS were 84% and 67%, respectively. Responses to splenectomy are not complete since extrasplenic disease persists. Patients with heavy bone marrow infiltration, lymphadenopathy or other disease localization besides the spleen are not good candidates for splenectomy. Furthermore splenectomy is a major surgical procedure accompanied by acute perioperative complications as well as late toxicities mainly due to infections. For that reasons splenectomy is not appropriate for elderly patients or patients with comorbidities with a high surgical risk. On the other hand rituximab monotherapy displays high efficacy with minimal toxicity. Several published series have shown an ORR more than 90%, with high CR rates (∼50%). The 10-year PFS and OS were 63% and 85%, respectively in a series of 104 SMZL patients. The role of rituximab maintenance has been investigated by only one group. Based on these data, maintenance with rituximab further improved the quality of responses by increasing significantly the CR rates (from 42% at the end of induction to 71% at the end of maintenance treatment), as well as the duration of responses: 7-year PFS was 75% for those patients who received maintenance vs 39% for those who did not (p < 0.0004). However no difference in OS has been noticed between the two groups, so far. Summarizing the above data, it is obvious that Rituximab monotherapy is associated with high response rates, long response duration and favorable safety profile, rendering it as the treatment of choice in SMZL.

Treatment of splenic marginal zone lymphoma.

Splenic marginal zone lymphoma (SMZL) is a distinct lymphoma entity characterized by an indolent clinical course and prolonged survival. Treatment is not standardized, since there are no prospective randomized trials in large series of SMZL patients. Splenectomy and rituximab represent the most effective treatment strategies used so far. The addition of chemotherapy to rituximab has not further improved the outcome, although this issue requires further investigation. Rituximab monotherapy has been associated with high response rates (∼90%), with approximately half of these responses being complete, even at the molecular level. More importantly, many of these responses are long-lasting, with a reported 7-year progression-free survival (PFS) at the rate of 69%. Maintenance rituximab treatment has been associated with further improvement of the quality of response as well as longer response duration in studies derived from one group of investigators. Based on its high efficacy and the good safety profile, rituximab represent one of the best treatment options for SMZL patients. Moreover, rituximab retains its efficacy in the relapse setting in most cases. Splenectomy is a meaningful alternative to rituximab in patients with bulky splenomegaly and cytopenias, without extensive bone marrow infiltration, who are fit for surgery. However splenectomy cannot completely eradicate the disease and it is also associated with greater morbidity or even mortality compared to rituximab. The choice of one of these two treatment approaches (rituximab or splenectomy) should mainly be based on patient's characteristics and on the disease burden. Novel agents are currently testing in low grade lymphomas including a small number of SMZL patients with promising results.

Treatment of splenic marginal zone lymphoma: should splenectomy be abandoned?

Splenic marginal zone lymphoma (SMZL) is a rare chronic B-cell lymphoproliferative disorder recognized as a distinct entity in the World Health Organization (WHO) classification. SMZL usually runs an indolent clinical course with a median survival of more than 10 years. However, in a proportion of patients (10-20%) SMZL behaves more aggressively, with a median survival of less than 4 years. Many efforts are ongoing to establish commonly accepted prognostic factors as a guide to therapy for this disorder. Data on the treatment of SMZL come from reported retrospective series including relatively limited numbers of patients. Despite these limitations, much progress has recently been made in the management of patients with SMZL. The oldest and most commonly used first-line therapeutic modality is splenectomy, which offers rapid alleviation of splenomegaly-related symptoms along with an improvement of cytopenias in the majority of patients, with a median PFS of 5 years. However, SMZL is a systemic disease, and splenectomy is not carried out with eradicative intent. Furthermore, splenectomy is a major surgical procedure with significant morbidity or even mortality, especially in older patients. Chemotherapy has only moderate activity in this form of MZL. Recent data suggest that rituximab is a very effective therapy with minimal toxicity and could replace splenectomy as first-line treatment. The overall response rate is > 90%, with almost half of responses being complete, while the 5-year progression-free survival is approximately 70%. The combination of rituximab with chemotherapy requires further evaluation. Based on the current data, splenectomy could be abandoned as first-line treatment for patients with SMZL.