Overall survival and post-spontaneous regression relapse-free survival of patients with lymphoproliferative disorders associated with rheumatoid arthritis: a multi-center retrospective cohort study

To clarify factors affecting 5-year survival rates and relapse rates after spontaneous regression (SR) of lymphoproliferative disorders (LPDs) in patients with rheumatoid arthritis (RA). This retrospective longitudinal study comprised 232 patients with RA diagnosed with LPDs between January 2000 and March 2017 at eight hospitals in Japan. The Kaplan-Meier method was used to analyze survival and the Cox proportional hazard model was applied to identify predictive factors. Among all patients, 1-, 2- and 5-year overall survival rates were 89.5%, 86.1%, and 78.2%, respectively. Multivariable analysis revealed four 5-year survival risk factors assessed at diagnosis: age above 70 years (p = .002), deep lymphadenopathy and/or more than one extranodal lesion (p = .008), Eastern Cooperative Oncology Group/Zubrod performance status of 2-4 (p = .004), and classic Hodgkin lymphoma (CHL) histology (p = .047). Among 143 patients who achieved SR, 2- and 5-year relapse rates were 14.2% and 24.9%, respectively. CHL histology (p = .003) and serum soluble interleukin-2 receptor levels exceeding 2000 IU/L (p = .014) were associated with post-SR relapse-free survival. Blood lymphocyte counts were significantly lower at relapse than at 3-6 months prior (p