Predicting the response to a bronchodilator in patients with airflow obstruction and lung cancer

The aim of the present study was to clarify the predictors of the response of patients with resectable lung cancer and untreated airflow obstruction to tiotropium, an antimuscarinic bronchodilator.

Tiotropium was administered to 29 preoperative patients with untreated airflow obstruction. The forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) were measured before and after the introduction of tiotropium. The response to tiotropium was determined based on the percentage gain in the FEV₁. The volume of the total lung area (TLV) and the low-attenuation area (LAA) was measured by deep inspiratory computed tomography based on the predefined thresholds for attenuation values.

The introduction of tiotropium resulted in a 15% gain in the FEV₁ (P < 0.001). A univariate regression analysis revealed that the FVC/TLV was the best predictor of the gain in FEV₁, followed by the FEV₁/FVC. Based on the results of a multiple regression analysis, a regression equation to predict a gain in the FEV₁ was generated using the FVC, TLV, and LAA. A receiver operating characteristic curve analysis revealed that this equation led to the highest area under the curve for predicting a major response to tiotropium, followed by the FVC/TLV and FEV₁/FVC. Postoperatively, six of the 20 minor responders experienced a progression of dyspnea. In contrast, none of the major responders experienced a progression of dyspnea (P < 0.05).

We developed an equation for predicting the response to tiotropium using parameters obtained from spirometry and quantitative computed tomography. A large-scale study to validate the usefulness of this equation is warranted.