Characteristics and survival outcomes of primary splenic cancers: A SEER population-based study

Primary splenic cancers represent a small number of cancer cases and studies on its clinicopathological features and outcomes are limited. Splenic lymphomas and primary splenic angiosarcoma (PSA) are the 2 most common histological types of splenic cancers. This population-based study aimed to investigate the clinical characteristics and survival outcomes of patients with splenic lymphomas or PSA. Patients diagnosed with splenic lymphomas or PSA between 2000 and 2015 were identified from the Surveillance Epidemiology and End Results database of the National Cancer Institutes. Overall survival (OS) and cancer-specific survival (CSS) rates were calculated using the Kaplan–Meier method. A Cox proportional hazard models were used to identify independent predictors of cancer-specific mortality. A total of 700 patients with splenic lymphoma and 48 patients with PSA were included in this study. The median age of patients with splenic lymphoma was 65 years and 57 years for patients with PSA. For patients with splenic lymphoma, the most prevalent histological subtypes were splenic marginal zone lymphoma and diffuse large B-cell lymphoma. A total of 52.6% of the cases had stage IV disease based on the Ann Arbor staging system. Five-year OS and CSS were 76.9% and 83.4%, respectively. Multivariate analysis revealed that independent predictors of splenic lymphoma CSS included race, stage, chemotherapy, and histological subtype. However, a much shorter OS time was seen in the PSA cohort which had a 5-year OS of 11.8%, a median OS of 10.0 months and the 5-year CSS of 12.4%. Chemotherapy was correlated with better outcomes in patients with PSA. However, the survival benefits of surgery for splenic cancer were not statistically significant in our study. The current study is the largest cohort of primary splenic cancer presented in literature based on the Surveillance Epidemiology and End Results database and our large series describe the characteristics and survival outcomes of such rare diseases which may provide reliable information for further studies and clinicians.