Splenectomy Is Still a Valid Option For Splenic Marginal Zone Lymphoma

Splenic marginal zone lymphoma (SMZL) is an indolent B-cell lymphoma characterized by splenomegaly, frequent moderate lymphocytosis with or without villous morphology and possible involvement of various organs, especially the bone marrow (BM). Diagnosis is classically based on the spleen histology, but it can be made on the BM biopsy, based on the typical intrasinusoidal cell infiltration pattern and immunohistochemistry. Different therapeutic options are available, but to date there are no conclusive comparative data.

We retrospectively analyzed 83 consecutive patients with a diagnosis of SMZL observed at our Institution between 1999 and 2013. The diagnosis was based on the BM biopsy in 79 patients; the BM was negative in 4 patients. Diagnosis was histologically confirmed on the spleen in 27 patients who underwent splenectomy. Patients presented a median age of 72.5 years (range 38-84); 43 were males. The median spleen size at diagnosis was 145 mm, ranging from 100 to 300 mm. The majority of patients were stage IV at diagnosis for BM infiltration (95%); B symptoms were present in 4 of them (4.8%). Forty-two patients (50.6%) had a lymphocytosis at diagnosis and 13 (15.6%) presented an IPI score higher than 3. Thirty-five of them (42%) had a MZL BM infiltration superior to 30% of the total bone cellularity. Forty-two patients (50.6%) underwent a watch and wait policy (WW), while 41 (49.4%) were treated within 6 months from diagnosis, mainly because of symptomatic splenomegaly; in these patients, treatment consisted of splenectomy, chemotherapy or chemotherapy plus immunotherapy with Rituximab. The features of patients submitted to WW with respect to patients treated at diagnosis were comparable for the various parameters mentioned above, except for spleen size (higher in patients treated at presentation) and lymphocyte count (higher in patients who were observed). After a median follow-up of 64 months, the overall median survival was 96%. Among the 42 WW patients, 18 (42.8%) are still untreated after a median follow-up of 57.5 months, while 24 (57.2%) have required therapy; the median treatment-free interval in these patients was 25.5 months. Concerning the 41 patients who underwent treatment at diagnosis, after a median follow-up of 50 months, 13 (31.7%) have required a subsequent second-line treatment. The interval between first-line approach and re-treatment in patients treated at diagnosis was 30 months. Overall, 27 patients were treated with splenectomy only (either at diagnosis or after a WW period): only 6 of them (22%) had a subsequent progression after a median latency of 42 months; 26 were treated with chemotherapy alone (alkylating agents in the majority of them, combination therapy in a minority): 15 of them (60%) had a subsequent relapse or progression after a median of 9 months; 12 patients received a Rituximab-containing regimen: of these, only 2 (16%) have so far required a second-line therapy after 10 and 26 months respectively.

The WW policy is a valid option for asymptomatic patients: in these patients, after 4.5 years from diagnosis more than 40% is still untreated. In patients requiring treatment, splenectomy alone is followed in the majority of patients by a long period of good disease control: only 22% required a second-line therapy after 3.5 years. The addiction of Rituximab to chemotherapy seems to reduce the probability of relapse and to prolong the response duration. However, these preliminary data need to be confirmed by larger studies.

No relevant conflicts of interest to declare.