Abstract

Background
There has been a resurgence of silicosis, particularly related to artificial stone. There are currently no treatments for silicosis beyond lung transplantation for end-stage disease. To evaluate the efficacy of prednisolone in people with artificial stone-associated silicosis–progressive massive fibrosis (PMF).
Methods
This was a pilot prospective observational clinical trial, assessing 3 months of prednisolone in adults with artificial stone–associated silicosis with PMF. Outcomes were assessed at 3 and 12 months.
Results
Seven participants completed the study. Baseline positron emission tomography (PET) scans demonstrated increased fluorine-18 fluorodeoxyglucose (18F-FDG) uptake in areas of PMF in all participants. All participants had a significant reduction in maximum standardized uptake value (SUVmax) following prednisolone at 3 months (pre-treatment mean SUVmax 6.7 [standard deviation (SD): 2.6], post-treatment mean SUVmax 4.2 [SD: 1.0], p = 0.01). There was also a non-significant reduction in the % of total lung parenchyma with SUV >1 (49.7% [SD: 36.4] to 45.8% [SD: 28.4], p = 0.52) and a significant reduction in SUV >2.5 (7.0% [SD: 6.3] to 2.4% [SD: 2.2], p = 0.03). There was a non-significant reduction in computed tomography ICOERD well-defined opacity profusion scores and large opacities. There was no significant difference in lung function or St. George's Respiratory Questionnaire. There were no serious adverse events.
Conclusions
There are high levels of inflammation in silicosis-PMF as evidenced by 18F-FDG PET. Short-term prednisolone reduced 18F-FDG PET activity. This suggests a possible therapeutic pathway for people with silicosis-associated PMF in a population with no current treatments. Further research is required to determine the most appropriate immunosuppressive strategy and further assess longer-term outcomes.

• Keywords: Silicosis; Occupational lung disease; Clinical trial; Prednisolone