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

Objectives: 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).

Methods: 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.

Results: 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 < .001).

Conclusion: Assessment of the above risk factors and routine inspection of blood lymphocyte counts could aid in the care management of LPDs in RA.