Pulmonary Function Test Can Predict Risk of Pneumonitis in Patients With NSCLC on Chemoradiotherapy

Researchers from Mexico recommend conducting a pulmonary function test in patients with non—small cell lung cancer (NSCLC) undergoing concurrent chemoradiotherapy (CCRT) to assess their susceptibility to developing radiation pneumonitis (RP).

The suggestion is based on the group’s findings that were recently published in the journal Respiratory Research.¹

Previous studies have shown that radiation exposure can cause pulmonary toxicity, which, in 15%-58% of patients can present as pneumonitis—a few studies have also documented mortality in this patient population. However, variables such as patient heterogeneity, radiation dose, and non-lung cancers have limited the use of predictive models, the authors write.

The current multi-institution study enrolled 52 patients who were undergoing treatment with carboplatin and paclitaxel along with CCRT for locally advanced and oligometastatic NSCLC. Patients—a near-even mix of males (21) and females (16)—were evaluated at baseline; at the end of CCRT; and at 6, 12, 24, and 48 weeks after receiving the chemoradiotherapy. A majority were smokers (20; 54.1%) and had a histological diagnosis of adenocarcinoma (25; 67.6%).

Patients completed forced spirometry with a bronchodilator, body plethysmography, impulse oscillometry, carbon monoxide diffusing capacity (DLCO), molar mass of CO2, 6-minute walk test and exhaled fraction of nitric oxide (FeNO). Radiation pneumonitis was assessed using Radiation Therapy Oncology Group (RTOG) and Common Terminology Criteria for Adverse Events (CTCAE).

Of the 37 patients who completed a 1-year follow-up, RP of grade 2 or higher was observed in 29% of (11/37) patients for RTOG and in 40% (15/37) patients for CTCAE. The study found that age (60 and above) and hypofractionated dose were associated with RP, measured using both RTOG and CTCAE scales.

An important observation was that pulmonary function test abnormalities at baseline, particularly lower forced expiratory volume in 1 second after bronchodilator, DLCO, and FeNO, the authors report.

However, gender or functional class were not observed as predicting factors for RP, at least in the present study. However, patients with impaired lung functional capacity prior to CCRT could increase the risk of RP, the authors explain, based on spirometry and FeNO results.

The authors note, however, that the small sample size of their study was a major limitation, but highlighted the 1-year follow-up and comprehensive evaluation of pulmonary function of the enrolled patients.

Reference

Torre-Bouscoulet L, Muñoz-Montaño WR, Martínez-Briseño D, et al. Abnormal pulmonary function tests predict the development of radiation-induced pneumonitis in advanced non-small cell lung cancer. Respir Res. 2018;19:72. doi: https://doi.org/10.1186/s12931-018-0775-2.