Evaluation of spirometry as a parameter of response to chemotherapy in advanced lung cancer patients: A pilot study

Spirometry is an important tool to monitor treatment response in diseases such as chronic obstructive pulmonary disease and asthma. However, there is lack of evidence to support its application to evaluate response to chemotherapy in advanced lung cancer. It might be a useful adjunct to the imaging-based response evaluation which lacks functional assessment of lungs.

The study was conducted to evaluate the change in spirometry in lung cancer patients after chemotherapy and to find its correlation with change in physical tumor size.

Sixty-two advanced lung cancer patients who were eligible for palliative chemotherapy were enrolled. Baseline tumor size evaluation using Response Evaluation Criteria in Solid Tumor (RECIST)-based scoring system, and spirometry was done. Four cycles of double agent (platinum doublets) chemotherapy were administered, after which treatment response was evaluated. Repeat spirometry was analyzed and correlated with changes in physical tumor size.

Twenty-five patients showed a response (all partial response) to four cycles of chemotherapy. Small cell carcinoma showed a better response rate than non-small cell carcinoma (78% vs. 39%). There was statistically significant improvement in forced expiratory volume in 1 (FEV₁) (P = 0.01) and forced vital capacity (P = 0.03) in responders as compared to nonresponders. Change in FEV1 showed a statistically significant correlation with the change in tumor size (RECIST score) (r = -0.34; P = 0.04).

Improvement in spirometry correlates with the tumor response as judged using RECIST criteria after chemotherapy. Further studies with bigger sample size are required to consolidate the results.