Diagnosing Pneumonitis in Patients With Inoperable NSCLC Is Challenging

Accurately diagnosing pneumonitis in patients undergoing immunotherapy (IO) treatment for inoperable stage III non-small cell lung cancer (NSCLC) is challenging, according to a study published in Radiotherapy and Oncology.

“In inoperable stage III NSCLC, the standard of care is chemoradiotherapy and adjuvant durvalumab for 12 months. Pneumonitis is the commonest toxicity leading to discontinuation of IO,” according to the researchers. “A failure to distinguish between expected radiation-induced changes, IO pneumonitis, and infection can lead to unnecessary durvalumab discontinuation.”

In this retrospective study, researchers analyzed 45 patients treated for stage III NSCLC with chemoradiotherapy and adjuvant durvalumab between 2018 and 2021. Using a published classification system, a thoracic radiologist reviewed baseline data and follow-up chest computed tomography (CT) scans for any features suspected of pneumonitis. After reviewing each patient’s case record, CT scans, and radiation fields, a final consensus diagnosis was made.

The analysis found that 31.1% of patients had pneumonitis scored in their patient records, and durvalumab was discontinued in 24.4%. The investigators noted that radiologist review led to a diagnosis of immune-related pneumonitis in only 13.3% of patients. Review by a pulmonary oncologist led to a diagnosis of immune-related pneumonitis in just 8.9%.

“In patients treated using the PACIFIC regimen, multidisciplinary assessment of CT scans, radiation doses, and patient symptoms resulted in fewer diagnoses of immune-related pneumonitis,” the researchers concluded. “Our study underscores the challenges in accurately diagnosing either IO-related or radiation pneumonitis in patients undergoing adjuvant immunotherapy after chemoradiotherapy and highlights the need for multidisciplinary review in order to avoid inappropriate cessation of adjuvant IO.”