Clinical course and prognosis of patients with lung cancer who develop anticancer therapy-related pneumonitis.

Background: Pneumonitis can be triggered by anti-cancer therapies: cytotoxic chemotherapy, tyrosine kinase inhibitors, and immune checkpoint inhibitors. There are few treatment options for patients who develop such pneumonitis and their treatment including chemotherapy is generally difficult thus would limit patient's prognosis. In this study, we investigated the clinical course of patients with lung cancer who developed anti-cancer therapy-related pneumonitis.
Patients and Methods: We retrospectively examined data of patients who had developed pneumonitis triggered by anti-cancer agents and required hospitalization from January 2014 to March 2019 and analyzed their subsequent clinical course and prognosis.
Results: The median age of the 58 study patients was 68 years and 82.8% were men. The median interval between first receiving the responsible agent and drug-induced pneumonitis was 7.4 weeks. Approximately 38% of patients were subsequently able to receive some anti-cancer therapy. The median post-pneumonitis overall survival (OS) from commencement of anti-cancer treatment was 13.2 months. No significant differences were found in survival time between treatment agents. However, patients who received some anticancer therapy after pneumonitis had significantly longer survival times than those did not (HR = 4.11, p = 0.0003) and patients who took longer to develop pneumonitis had a longer survival (HR = 2.28, p = 0.0148). Multivariate analysis revealed that short interval to onset and no post-pneumonitis anticancer therapy were independent predictors of short survival.
Conclusion: Although patients who developed pneumonitis had relatively short survival times, the interval between initial therapy and pneumonitis had survival impact. Survival can be prolonged by administering further cancer treatment after resolution of pneumonitis.