The real-world incidence of grade 3-5 chemoradiation (CRT)-induced pneumonitis in patients with unresectable, stage III non-small cell lung cancer (NSCLC) may be higher than the incidence reported in randomized clinical trials (RCTs), a meta-analysis suggests. 

Researchers found that the pooled incidence of CRT-induced grade 3-5 pneumonitis was 3.62% in RCTs, 5.98% in observational studies, and 7.85% in observational studies of platinum doublet chemotherapy.

These results were published in the journal Lung Cancer


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The meta-analysis included 11 studies with a total of 1788 patients. All patients had unresectable, stage III NSCLC and underwent concurrent CRT.

There were 5 RCTs, including a total of 1106 patients, in which researchers reported the incidence of grade 3-5 CRT-induced pneumonitis. The incidence ranged from 0% to 8.3% in these trials, for a pooled incidence of 3.62%.

There were 5 observational studies, including a total of 636 patients, in which researchers reported the incidence of grade 3-5 CRT-induced pneumonitis. The incidence ranged from 1.3% to 10.8% in these studies, for a pooled incidence of 5.98%.

The researchers also looked at the incidence of fatal pneumonitis alone. These data were available from all 5 RCTs (1106 patients) and 6 observational studies (682 patients). 

In the RCTs, the rate of grade 5 pneumonitis ranged from 0% to 5.2%, for a pooled incidence of 0.37%. In the observational studies, the rate of fatal pneumonitis ranged from 0% to 4.9%, for a pooled incidence of 1.73%.

The researchers also assessed the impact of platinum-based doublet chemotherapy, as opposed to single-agent cisplatin chemotherapy. All but 1 observational study included doublet chemotherapy, so the researchers excluded that study from their analysis. 

Among patients who received platinum doublet chemotherapy, the pooled incidence of grade 3-5 CRT-induced pneumonitis was 7.85%. The pooled incidence was 2.32% for grade 5 pneumonitis alone and 5.34% for grade 3-4 pneumonitis only.

“These results suggest that, when combined with radiotherapy, platinum-based doublet chemotherapy may be associated with a higher risk of pneumonitis than cisplatin as a single chemotherapy,” the researchers wrote. “Moreover, these results demonstrate that the pooled incidence of [CRT-induced pneumonitis] in the real-world setting may be slightly higher than when compared with RCTs.”

Disclosures: This research was sponsored by Merck Sharp & Dohme LLC. All study authors are employed by either Merck or IQVIA.

Reference

Kuang Y, Pierce CM, Chang H-C, et al. Chemoradiation-induced pneumonitis in patients with unresectable stage III non-small cell lung cancer: A systematic literature review and meta-analysis. Lung Cancer. Published online June 11, 2022. doi:10.1016/j.lungcan.2022.06.005