A multicenter retrospective study investigating the incidence of pneumonitis and the incidence, risk factors, and clinical characteristics of radiation recall pneumonitis in patients with non–small cell lung cancer (NSCLC) who had received nivolumab found the incidence of radiation recall pneumonitis was 5.4% among patients with a previous history of thoracic radiation therapy, although there were no significant risk factors of radiation recall pneumonitis. In addition, patients with radiation recall pneumonitis pattern had relatively better outcomes compared with patients exhibiting other radiologic patterns of pneumonitis. The study by Shimokawaji et al was presented at the 2020 ASCO-SITC Clinical Immuno-Oncology Symposium (Abstract 88).
Radiation recall pneumonitis is a pneumonitis localized to a previously irradiated field after exposure to a systemic agent. With the advent of immunotherapy—which has its own baseline risk of pneumonitis—in the treatment of various malignancies, including lung cancer, it is important to investigate the likelihood of the development of radiation recall pneumonitis in patients who were previously treated with radiation therapy.
The researchers analyzed the medical records of 669 patients with NSCLC who had received nivolumab between December 2015 and March 2017. The incidence of pneumonitis and the incidence, risk factors, and clinical characteristics of radiation recall pneumonitis were analyzed at five institutions. An examination of the patient’s age, sex, smoking history, performance status at the start of nivolumab treatment, lung disease background, history of previous radiation pneumonitis, total radiation dose, volume receiving more than 20 Gy or 30 Gy, mean lung dose of thoracic radiation therapy, and duration after thoracic radiation therapy was conducted to identify potential risk factors for radiation recall pneumonitis. Radiation recall pneumonitis was defined as fibrosis or consolidation occurring in the previous thoracic radiation therapy field, and imaging analysis was conducted by two radiologists.
Among the 669 patients evaluated, the researchers found the incidences of all-grade and ≥ grade 3 pneumonitis were 8.8% (59 of 669) and 6.2% (18 of 669), respectively. The incidence of radiation recall pneumonitis was 5.4% (14 of 257) among patients with a history of previous thoracic radiation therapy. There were no significant risk factors for radiation recall pneumonitis. Although the researchers did not find significant difference between the severity of radiation recall pneumonitis pattern and other radiologic patterns of pneumonitis, patients with radiation recall pneumonitis showed better outcomes. All patients recovered from radiation recall pneumonitis without exacerbation or death, compared to 9.3% of exacerbation or death in other patterns of pneumonitis.
“Incidence of radiation recall pneumonitis was 5.4% among patients with [a] history of previous thoracic radiation therapy, although there were no significant risk factors of radiation recall pneumonitis. Patients with radiation recall pneumonitis pattern showed relatively better outcome,” concluded the researchers.
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