Abstract
AIM: The present study assessed the incidence of drug-induced interstitial lung disease (ILD) recurrence among breast cancer patients who underwent rechallenge with cancer-directed therapy. MATERIALS & METHODS: Japanese insurance claims data and the Diagnosis Procedure Combination database (2009-2022) involving 81,601 patients were analyzed to evaluate 1,042 breast cancer patients who developed ILD. Of these, 566 patients underwent cancer-directed therapy rechallenge, and 42.1% of them were re-challenged with the same therapeutic regimen that caused the initial ILD. RESULTS: ILD recurrence was observed in 18.9% of the patients, with a median recurrence time of 40 days. The drugs most commonly causing ILD were cytotoxic agents, and those most frequently used for rechallenge were cytotoxic agents. CONCLUSION: A notable ILD recurrence rate was observed in breast cancer patients after a cancer-directed therapy rechallenge, highlighting the need for cautious treatment planning and personalised strategies to balance cancer control while mitigating ILD risk.