In prospective case series evaluating standardized clinical protocols for chronic cough, the prevalence of malignancy was found to be between 1% and 2% [7,17]. CT of the chest is recommended for the evaluation of suspected pulmonary neoplasm [15,53] and has been recommended for patients with chronic cough who are smokers or when chronic lung disease is clinically suspected [16,53]. Chest CT has been shown to be more sensitive than chest radiography for the detection of lung cancer in the National Lung Cancer Screening Trial [25], with significant overall mortality benefit. There is limited data regarding the differential imaging evaluation of patients with chronic cough with occupational exposures. In a small sample of male welders (n = 74) with a normal chest radiograph, HRCT identified 27 patients with micronodular disease, 5 patients with emphysematous changes, 3 patients with GGO, and 1 patient with pleural thickening [51], questioning the sensitivity of radiography for occupational disease. Red flags and concerning features are discussed by various authors and larger pulmonary societies [1,13,29], although our literature review did not identify studies directly evaluating CT of the chest in patients with chronic cough with elevated risk. Additionally, red flags in this setting have not been validated and shown to be predictive of malignancy. In the setting of elevated lung cancer risk, there is no high-quality evidence supporting chest CT in patients with chronic cough. It is worth noting that in the few case series evaluating patients with chronic cough, malignancy was diagnosed in 1% to 2% of studied groups. This is a not an insignificant quantity and actually rivals case detection in both lung cancer and breast cancer screening. Furthermore, at least two of these reported malignancies were in the context of a normal chest radiograph. It is likely that the prevalence of malignancy in the setting of chronic cough is far lower, and these studies are likely biased by selection.
Chronic Cough. In prospective case series evaluating standardized clinical protocols for chronic cough, the prevalence of malignancy was found to be between 1% and 2% [7,17]. CT of the chest is recommended for the evaluation of suspected pulmonary neoplasm [15,53] and has been recommended for patients with chronic cough who are smokers or when chronic lung disease is clinically suspected [16,53]. Chest CT has been shown to be more sensitive than chest radiography for the detection of lung cancer in the National Lung Cancer Screening Trial [25], with significant overall mortality benefit. There is limited data regarding the differential imaging evaluation of patients with chronic cough with occupational exposures. In a small sample of male welders (n = 74) with a normal chest radiograph, HRCT identified 27 patients with micronodular disease, 5 patients with emphysematous changes, 3 patients with GGO, and 1 patient with pleural thickening [51], questioning the sensitivity of radiography for occupational disease. Red flags and concerning features are discussed by various authors and larger pulmonary societies [1,13,29], although our literature review did not identify studies directly evaluating CT of the chest in patients with chronic cough with elevated risk. Additionally, red flags in this setting have not been validated and shown to be predictive of malignancy. In the setting of elevated lung cancer risk, there is no high-quality evidence supporting chest CT in patients with chronic cough. It is worth noting that in the few case series evaluating patients with chronic cough, malignancy was diagnosed in 1% to 2% of studied groups. This is a not an insignificant quantity and actually rivals case detection in both lung cancer and breast cancer screening. Furthermore, at least two of these reported malignancies were in the context of a normal chest radiograph. It is likely that the prevalence of malignancy in the setting of chronic cough is far lower, and these studies are likely biased by selection.