Primary renal lymphoma: a population-based study in the United States, 1980-2013

Primary renal lymphoma (PRL) is a rare lymphoid malignancy with only a few cases reported in the literature. We performed a population-based study of PRL to determine its incidence, clinical characteristics and factors associated with survival using the Surveillance, Epidemiology, and End Results (SEER) database. We identified 723 patients with PRL. The most common histological subtype of PRL was diffuse large B-cell lymphoma (56.3%). The incidence and mortality rate of PRL was 0.053/100,000 person-years and 0.036/100,000 person-years, respectively. The incidence rate of PRL was increasing significantly with an annual percentage change (APC) of 3.45% (p < 0.001). The 1-year and 5-year relative survival (RS) rates of patients with PRL were 78% and 64%. The RS of patients diagnosed between 2000 to 2013 was better than that of patients diagnosed between 1980-1999. A multivariate Cox hazards regression analysis revealed that older age, male gender, diagnosis before 2000, advanced stage, not receiving surgical treatment, and DLBCL or T/NK cell lymphoma type were independent predictors of unfavorable survival.