Sjögren’s disease patients, their relatives face higher cancer risk: Study
Findings support integrating family cancer history into clinical assessment
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People with primary Sjögren’s disease and their close family members have a higher risk of developing cancer than the general population, according to a study out of Turkey.
While Sjögren’s has been associated with a higher risk of cancer, the potential risk among family members is a new finding. It supports the hypothesis that the environmental and genetic factors that contribute to Sjögren’s may be related to cancer risk independently of the disease itself, researchers noted.
“These findings strongly advocate for the integration of comprehensive family cancer history into the clinical assessment of individuals with [Sjögren’s disease] and underscore the potential utility of implementing proactive screening strategies and enhanced surveillance protocols for their at-risk relatives,” researchers wrote.
The study, “Risk of Cancer in Patients With Primary Sjögren’s Disease and Their Relatives,” was published in the International Journal of Rheumatic Diseases.
Genetics, environmental exposures may contribute to Sjögren’s
Sjögren’s is an autoimmune condition marked by symptoms of dry eyes and dry mouth, though the disease can affect several parts of the body.
In primary Sjögren’s, the disease occurs on its own rather than as a complication of another autoimmune disorder. The underlying causes of Sjögren’s remain unclear. However, scientists believe that a combination of genetics and environmental exposures may contribute.
“It has been shown that patients diagnosed with [Sjögren’s disease] have an increased risk for both solid and [blood cancers] compared to the general population,” the researchers wrote, with the strongest association being for non-Hodgkin lymphoma, a type of blood cancer.
Researchers are still investigating what links Sjögren’s to cancer. It is possible that the genetic and environmental factors that cause Sjögren’s also increase the risk of cancer. If this were the case, the families of people with Sjögren’s, who typically have overlapping genetics and exposures, would also be at a higher risk of cancer. However, little research has systematically examined this risk.
To learn more, a team of researchers recruited 323 adults with Sjögren’s who were followed at a single Turkish center. Nearly all (97%) were women, and their mean age was 56. These participants completed interviews about their own cancer history, as well as cancer among their parents, children, and siblings. Participants were followed for a median of 3.6 years.
Rates of cancer 3.3 times higher among people with Sjögren’s
The researchers compared cancer rates in Sjögren’s patients and their relatives with that reported for the general population of Turkey using a metric called the standardized incidence ratio (SIR).
Among people with Sjögren’s, 29 (9%) had been diagnosed with cancer, most commonly more than a year prior to receiving a Sjögren’s diagnosis (51%). Most cases of cancer (65.5%) involved solid tumors (most frequently breast cancer), while the remaining 34.5% involved blood cancers.
The SIR for cancer overall was 3.3, suggesting that rates of cancer were 3.3 times higher among people with Sjögren’s than would be expected based on general population data. The SIR for blood cancer specifically was 22.5, indicating a greater elevation in risk than for cancer overall.
The cancer rate was higher among Sjögren’s patients whose close family members also had cancer (15%) compared with those without (4.2%).
“Our findings underscore the importance of systematically obtaining a detailed family history of cancer during the clinical evaluation of patients with primary Sjögren’s disease,” the team wrote, adding that this could help evaluate each patient’s risk level.
These findings suggest that genetic and environmental factors associated with Sjögren’s disease may increase cancer risk not only in affected patients but also in healthy individuals within the same family.
Participants answered questions about cancer history for a total of 1,750 close relatives. About 10% had experienced cancer, resulting in an SIR of 3.5 — comparable with the SIR among people with Sjögren’s.
“These findings suggest that genetic and environmental factors associated with Sjögren’s disease may increase cancer risk not only in affected patients but also in healthy individuals within the same family,” the researchers wrote.
Family members had higher rates of several solid cancers, including those affecting the lungs, gastrointestinal tract, and brain. In contrast, the SIR of blood cancer was 4.6 times higher among people with Sjögren’s than in their relatives.
“Importantly, while the malignancy spectrum partially overlapped between patients and their relatives, the magnitude of cancer risk was consistently highest in patients with Sjögren’s syndrome, followed by lower levels in first-degree and close relatives,” the team wrote. “This risk gradient suggests that the excessive cancer burden in Sjögren’s [disease] reflects a combination of disease-related factors and shared familial predisposition.”
These findings indicate that Sjögren’s patients and their close relatives may benefit from regular monitoring for cancer, as this could potentially help identify and diagnose tumors earlier.
Among the study’s limitations, the team emphasized its single-center nature, the fact that it relied on patient-reported data alone, and its short follow-up duration. Because some cancers may take longer to develop, this relatively short follow-up may have led to an underestimation of cancer risk.
“Larger studies with longer follow-up are needed to further elucidate the biological mechanisms underlying this association,” the researchers concluded.
