Is primary Sjögren's syndrome a risk factor for malignancies different from lymphomas? What does the literature highlight about it?

Increased prevalences of head and neck cancers in patients with Sjögren's syndrome

OBJECTIVE

This study aimed to investigate prevalences of head and neck cancers in patients with and those without Sjögren's syndrome using a population-based dataset.

METHODS

We retrieved sampled patients from Taiwan's Longitudinal Health Insurance Database. This study included 38 930 patients with Sjögren's syndrome and 155 720 propensity-score matched comparison patients without Sjögren's syndrome.

RESULTS

Chi-squared tests revealed that there was a statistically significant difference in the prevalences of head and neck cancers between patients with Sjögren's syndrome and comparison patients (1.77% vs. 1.22%, p < 0.001). The odds ratio for head and neck cancers for patients with Sjögren's syndrome relative to the comparison group was 1.452 (95% CI = 1.325-1.592).

CONCLUSIONS

Our study demonstrated that patients with Sjögren's syndrome face increased odds of head and neck cancers, encompassing several sites including the oral cavity, oropharynx, nasopharynx, and thyroid.

Causal associations of Sjögren's syndrome with cancers: a two-sample Mendelian randomization study

BACKGROUND

Several observational studies have explored the associations between Sjögren's syndrome (SS) and certain cancers. Nevertheless, the causal relationships remain unclear. Mendelian randomization (MR) method was used to investigate the causality between SS and different types of cancers.

METHODS

We conducted the two-sample Mendelian randomization with the public genome-wide association studies (GWASs) summary statistics in European population to evaluate the causality between SS and nine types of cancers. The sample size varies from 1080 to 372,373. The inverse variance weighted (IVW) method was used to estimate the causal effects. A Bonferroni-corrected threshold of P < 0.0031 was considered significant, and P value between 0.0031 and 0.05 was considered to be suggestive of an association. Sensitivity analysis was performed to validate the causality. Moreover, additional analysis was used to assess the associations between SS and well-accepted risk factors of cancers.

RESULTS

After correcting the heterogeneity and horizontal pleiotropy, the results indicated that patients with SS were significantly associated with an increased risk of lymphomas (odds ratio [OR] = 1.0010, 95% confidence interval [CI]: 1.0005-1.0015, P = 0.0002) and reduced risks of prostate cancer (OR = 0.9972, 95% CI: 0.9960-0.9985, P = 2.45 × 10-5) and endometrial cancer (OR = 0.9414, 95% CI: 0.9158-0.9676, P = 1.65 × 10-5). Suggestive associations were found in liver and bile duct cancer (OR = 0.9999, 95% CI: 0.9997-1.0000, P = 0.0291) and cancer of urinary tract (OR = 0.9996, 95% CI: 0.9992-1.0000, P = 0.0281). No causal effect of SS on other cancer types was detected. Additional MR analysis indicated that causal effects between SS and cancers were not mediated by the well-accepted risk factors of cancers. No evidence of the causal relationship was observed for cancers on SS.

CONCLUSIONS

SS had significant causal relationships with lymphomas, prostate cancer, and endometrial cancer, and suggestive evidence of association was found in liver and bile duct cancer and cancer of urinary tract, indicating that SS may play a vital role in the incidence of these malignancies.

Primary Sjögren's syndrome is associated with increased risk of malignancies besides lymphoma: A systematic review and meta-analysis

OBJECTIVE

Patients with primary Sjögren's syndrome(pSS) have increased risk of non-Hodgkin lymphoma (NHL). However, whether pSS patients have increased risk of other malignancies is unclear. The aim of this study is to investigate the association between pSS and the risk of malignancy, with a focus on hematological malignancies besides lymphoma and solid tumors through a systematic review and meta-analysis.

METHOD

We searched PubMed and EMBASE by March 21st 2021. Inclusion criteria were as follows: (1) pSS was the exposure of interest; (2) newly developed malignancies were the outcome of interest; (3) standardized incidence ratio or relative risk with 95% confidence interval or essential data to calculate them were reported. (4) Study design was cohort study. Patient with other connective diseases were excluded. Quality assessment was conducted according to Newcastle-Ottawa Scale for cohort study. Random or fixed effect models were used to calculate the pooled SIR according to heterogeneity measured by I².

RESULTS

A total of 1003 articles were found by a comprehensive search in PubMed and EMBASE. Twenty-eight articles were eligible. Four of them were from the same database, the one with longest observational span was chosen. Therefore, twenty-five articles were included for final analysis, which involved more than 47,607 pSS patients with the follow-up of more than 452,468 person-year. We found that pSS was significantly associated with increased risks of overall malignancy(pooled SIR 2.17, 95%1.57-3.00), hematological malignancy(pooled SIR 11.55, 95%CI 4.32-30.90) including NHL(pooled SIR 13.71, 95%CI 8.83-21.29), Hodgkin lymphoma(pooled SIR 8.84, 95%CI 5.00-15.61), multiple myeloma(pooled SIR 8.27, 95%CI 3.08-22.24), leukemia(pooled SIR 2.56, 95%CI 1.78-3.69) and solid tumors(pooled SIR 1.39, 95%CI 0.90-2.13) including lung cancer(pooled SIR 1.55, 95%CI 1.29-1.85), thyroid cancer(pooled SIR 2.05, 95%CI 1.20-3.48), non-melanoma skin cancer(pooled SIR 1.71, 95%CI 1.08-2.72), kidney/urinary tract cancer(pooled SIR 1.36, 95%CI 1.02; 1.81), liver cancer(pooled SIR 1.70, 95%CI 1.13-2.57) and prostate cancer(pooled SIR 1.50, 95%CI 1.02-2.22).

CONCLUSION

This meta-analysis showed that pSS patients had increased risk of overall cancer, which not only contributed by NHL, but also by other hematological malignancies and solid tumors.