Primary Sjögren syndrome bidirectionally linked to non-Hodgkin lymphoma

A bidirectional relationship is observed between primary Sjögren syndrome (pSS) and non-Hodgkin lymphoma (NHL), reports a nationwide population-based study in Taiwan.

The authors carried out this study to determine whether there existed a bidirectional association between pSS and NHL. They used the National Health Insurance Research Database to identify 15,636 patients with new-onset pSS without previous cancer and 25,074 with new-onset NHL without previous pSS as two nonoverlapping cohorts from 1998 to 2012. Participants were followed until 2013.

Standardized incidence ratios (SIRs) for NHL in patients with pSS and SIR for pSS in those with NHL were compared with the general population.

Of the 15,636 patients with pSS, 741 developed cancers, with 51 cases of NHL. The highest incidence of specific cancer risk in patients with pSS was that for NHL (SIR, 4.6, 95 percent confidence interval [CI], 3.4–6.0). Forty-nine out of 25,074 patients with NHL developed pSS, and the incidence was also elevated (SIR, 3.2, 95 percent CI, 2.4–4.2).

Of note, the highest risk was observed within 1 year after the diagnosis of either pSS or NHL.

“Our findings suggest being alert for patients with pSS or NHL who have early signs of the other disease in clinical care,” the authors said. “The underlying mechanisms of the bidirectional relationship merit further investigation.”