Risk Factors Associated with Malignant Lung Nodules in Smokers with Coal Worker’s Pneumoconiosis: An Exploratory Case-control Study

Benign lung nodules (LN) in coal worker’s pneumoconiosis (CWP) may be indistinguishable from lung cancer (LC) on radiography. There is a lack of validated LN risk calculators and LN management guidelines for CWP patients.

We sought to identify characteristics predictive of LC in LN detected in smokers with CWP.

An exploratory case-control study was conducted between 2015 to 2020. All adult ever-smokers with radiographic-proven CWP and LN, which were biopsied, were included. Multivariable logistic regression models were used to quantify adjusted associations between demographic and radiographic characteristics.

Of the 29 eligible patients, 15 (52%) had biopsy-proven LC and 14 (48%) had benign LN. Solid LN increased the odds of LC by 21.6 times (p=0.17). Patients with radiographic emphysema were 2.21 times more likely to have a malignant LN (p=0.51). LN spiculation was associated with a higher risk of LC (OR=1.73, p=0.72), as was the presence of a solitary LN (OR=9.35, p=0.13). Multiple LN was found to be negatively associated with LC (OR=0.18, p=0.36). Family history of LC, pack-years of smoking, and exposure to silica and/or coal were not found to be predictive of malignancy (OR≤1, p>0.05).

Solid and spiculated LN associated with emphysema and multiple LN was found to be correlated with a higher risk for LC in CWP ever-smokers. No statistically significant association was found due to the small number of patients. This study highlights unique LN features conferring a higher risk of LC among smokers with CWP. Larger, prospective, multicentric studies should be conducted to confirm these findings.

The clinical trial registration number approved by the Institutional Review Board, West Virginia University, was #2109411710.