Survival with splenectomy in splenic marginal zone lymphoma: Analysis of the Surveillance, Epidemiology and End Results (SEER) database.

Abstract

8044 Background: The role of splenectomy as the primary therapy for splenic marginal zone lymphoma has been questioned. We studied relative survival in SMZL and the impact of splenectomy on lymphoma-specific survival (LSS). Methods: SMZL cases (diagnosed in 1993-2008) were derived from the SEER database. Age, sex and race-matched actuarial survival data were summarized. Factors predictive of splenectomy were studied using logistic regression with a subsequent propensity score (PS)-weighted survival analysis. Results: 1071 patients were identified with a median age of 69 years (range, 25-96) and a median follow up of 33 months. 53% were women and 92% were white. 70% of the lymphomas were stage III/IV with B symptoms recorded in 22.3%. 54% of patients underwent splenectomy. The significant factors predictive of surgery included younger age (p<10-14), stage I/II (p<10-15), B-symptoms (p=0.003), no prior malignancy (p=0.002), with significantly lower rates in black patients (OR 0.41, 95%CI 0.21-0.80, p=0.008), on the Pacific Coast (OR 0.62, 95%CI 0.47-0.81, p=0.0004) and with decreasing rates over time (p=0.0002). The actuarial 5-year relative survival was 82.8% (95%CI 77.9-86.7%) with no difference by sex (p=0.79), race or stage. 54% of deaths were related to SMZL with the estimated LSS of 80.8% (95%CI 78-84%). Splenectomy was not associated with improved LSS in propensity score-stratified log-rank test (p=0.60) or in the PS-weighted Cox model (HR=0.93, 95%CI 0.62-1.38, p=0.70). Advancing age (HR 1.05, 95%CI 1.03-1.07, p<10-8) and presence of B-symptoms (HR=1.98, 95%CI 1.30-3.01, p=0.002) were significantly predictive of death from SMZL, with no evidence of improvement in LSS over the years (HR=0.97, 95%CI=0.91-1.03, p=0.34). There was also no detectable impact of splenectomy on survival in patients who ultimately died of SMZL (p=0.83). Conclusions: In this cohort, the largest studied to date, splenectomy did not demonstrate a survival benefit in SMZL. Patients continue to have decreased survival despite advances in other indolent B-cell lymphomas. The role of splenectomy versus chemoimmunotherapy remains to be determined.