Close relatives of Sjögren’s disease patients also at increased risk of cancer

Patients with Sjögren’s disease (SjD) have a heightened risk of cancer, and this risk increase extends to their first-degree relatives, according to a study.

The study included 323 primary SjD patients (mean age 56 years, 97 percent female) who were actively followed-up in the rheumatology outpatient clinic at Gazi University Hospital in Turkey and their 1,750 close relatives (parents, siblings, and children).

Researchers analysed data on cancer history in patients and their relatives collected through direct face-to-face interviews and telephone surveys. The risk of developing cancer was evaluated by comparing it with that in the general population, with data obtained from the Global Cancer Observatory of the World Health Organization International Agency for Research on Cancer.

Of the SjD patients, 29 (9 percent) had a history of malignancy, including solid organ tumours in 5.9 percent and haematological malignancies in 3.1 percent. Breast cancer was the most common solid tumour.

The standardized incidence ratio (SIR) for all cancers was 3.3 (95 percent confidence interval [CI], 2.2–4.7; p<0.001) during a median follow-up of 3.6 years. Looking at specific malignancies, the SIRs were 22.5 (95 percent CI, 10.8–41.4; p<0.001) for leukaemia or lymphoma and 3.8 (95 percent CI, 1.5–7.9; p<0.001) for breast cancer.

Malignancy risk in patients with SjD was not modified by age, gender, smoking history, Schirmer test result, laboratory parameters including anti-SSA, anti-SSB, ANA, complement levels, ESSDAI status, or Focus score. However, the risk increase appeared to be greater in patients who had close relatives with cancer.

A total of 128 patients with SjD (43.3 percent) had at least one close relative with cancer (average age 58 years, 56 percent male, 7.4 percent active smokers), with 176 cancer cases in total. The SIR of cancer among close relatives of patients with SjD was 3.5 (95 percent CI, 3.0–4.1; p<0.001).