Radiation recall pneumonitis is an inflammatory reaction that involves previously irradiated tissue, and which may be triggered by an anticancer drug or vaccine.
Clinical features:
(1) history of radiation therapy with lungs in the radiation field, sometimes years earlier
(2) exposure to a triggering agent
(3) onset of cough, shortness of breath, chest tightness and low-grade fever
(4) pneumonitis more severe in previously irradiated lung fields
(5) exclusion of pneumonia or other cause for the clinical findings
Triggers may include:
(1) immune checkpoint inhibitors (PD-1, PD-L1)
(2) COVID-19 vaccine
(3) chemotherapeutic agents (paclitaxel, gemcitabine, other)
(4) tyrosine kinase inhibitors
Risk factors may include:
(1) age > 70 years
(2) pre-existing interstitial lung disease
