Incidence of malignancy in systemic sclerosis: A systematic review and meta-analysis

SSc is associated with increased malignancy risk, a growing cause of mortality in SSc. However, standardised incidence ratios (SIR) vary widely across studies and different malignancy subtypes. This meta-analysis aimed to determine the SIR of different malignancy subtypes and the temporal relationship with SSc diagnosis.

A systematic review and meta-analysis were conducted by searching Embase, MEDLINE and Cochrane Library databases from inception to 7 December 2024. Cohort studies reporting SIRs of malignancies in SSc patients were included. Studies where SIR was not reported were excluded. Random-effects models were used to calculate pooled estimates, while study quality was assessed using the Newcastle-Ottawa Scale. This review is registered on PROSPERO (CRD42023445876).

Thirty-one cohort studies comprising at least 32,134 SSc patients were included. Overall malignancy risk was significantly increased (SIR 1.66; 95% CI 1.32 - 2.08). Highest risks were observed for esophageal, liver, cervical, lung, and haematological malignancies (SIR 3.35 - 13.95), while breast malignancy showed modest increased risk (SIR 1.34, 95% CI 1.00 - 1.80) that was not statistically significant. High-quality studies confirmed these associations except for esophageal malignancy, with only one high quality study for liver malignancy. There was a mean interval of 7.4 years (95% CI 5.3 - 9.5) between SSc and malignancy diagnosis.

Our findings confirm an increased malignancy risk, particularly lung, haematological and cervical malignancies, and an approximate 7-year interval between SSc diagnosis and malignancy development. Further studies are needed to clarify the risk factors for different malignancy subtypes to develop cancer screening strategies.

NIL.