AB0835 CANCER FREQUENCY IN CLOSE RELATIVES OF PATIENTS WITH SJÖGREN’S SYNDROME
Authors: T. Uğur Tuzcu, R. C. Kardaş, İ. Vasi, D. Yildirim, B. Kaya, R. Duran, A. Erden, H. Küçük, M. A. Öztürk, B. Göker
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> In patients diagnosed with Sjögren's syndrome (SjS), there is an increased risk of hematologic malignancies, and predictive factors are well-known. Familial clustering and HLA haplotype association suggest that genetic factors disrupting the regulation of the immune system may predispose individuals to both neoplasms and autoimmune diseases, potentially leading to an increased frequency of cancer development in close relatives of SjS patients. <h3>Objectives:</h3> In this study, our aim was to assess the frequency of cancer development in close relatives of individuals diagnosed with SjS. <h3>Methods:</h3> Consecutive patients who were actively followed up in the rheumatology outpatient clinic at Gazi University Hospital and who met the 2016 ACR-EULAR classification criteria for SjS were included in the study. Direct interviews were conducted with the patients, and communication was established through telephone numbers registered in the hospital system. The risk of developing acancer in SjS patients and their first-degree relatives was calculated by comparing it with the general population of Turkey. Cancer incidence data for the general population of Turkey were obtained from the Global Cancer Observatory of the World Health Organization International Agency for Research on Cancer (GLOBOCAN). <h3>Results:</h3> 323 SjS patients (F/M: 313/10, mean age: 56±11), 9% (n=29) had a history of malignancy, with 5.9% (n=19) having solid organ malignancy and 3.1% (n=10) hematologic malignancy. Breast cancer was the most common at 2.2%, and other cancers (bladder, rectum, cervix, endometrium, colon) were observed in 1.5%. The median follow-up was 3.58 years, and the standardized incidence ratio (SIR) for all cancers was 3.3 (95% CI: 2.2–4.7, P&lt;0.001). Leukemia or lymphoma cases had an SIR of 22.5 (95% CI: 10.8–41.4, P&lt;0.001). Among 313 women, seven cases of breast cancer had an SIR of 3.8 (95% CI: 1.5–7.9, P&lt;0.001). Malignancy development in SjS patients did not differ based on age, gender, SjS type, smoking history, Schirmer, anti-SSA, anti-SSB, ANA, ESSDAI positivity-negativity, complement levels, and Focus score. 43.3% of SjS patients (n=128) had a family history of cancer (parents, siblings, children), totaling 176 cases (Table 1). Among 1750 relatives, the SIR was 3.5 (95% CI: 3.0-4.1, P&lt;0.001). Notably, specific cancers showed varying SIRs: lung (2.66), breast (4.6), colon (3.7), stomach (4.3), prostate (2.8), brain tumor (4.6), laryngeal (7.8), endometrium (5.5), ALL (4.9), liver (4.1), and kidney tumor (4.6) (Table 2). The average age of relatives with cancer was 58±10 years; 56% were male, and 7.4% were active smokers. No significant differences were found in SjS type, Schirmer result, focus score, SSA, SSB, ANA, RF, complement levels, IgA, IgM, IgG levels, and ESSDAI status when comparing SjS patients with and without relatives with cancer. <h3>Conclusion:</h3> In our study, we found that close relatives of SjS patients have an increased risk of developing cancer compared to the general population. No study was found in the literature that investigated the incidence of cancer in close relatives of SjS patients. There is a need for larger population-based studies on this topic to clarify this association. <h3>REFERENCES:</h3> <b>NIL.</b> <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>