Interstitial lung disease recurrence on chemotherapy rechallenge in breast cancer: a nationwide Japanese database

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.
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.
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.  
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.
This article discusses a study that researched a lung condition known as interstitial lung disease (ILD) in individuals with breast cancer who were treated again with cancer-directed therapy after recovering from ILD. ILD involves inflammation and damage to the lungs and can be a serious side effect of cancer treatment.
We analyzed data from Japanese health insurance claims and hospital records from 2009 to 2022, of 81,601 patients with breast cancer, 1,042 developed ILD that required treatment with steroids. Of the 1,042 patients, 566 underwent cancer-directed therapy again after their initial ILD episode.
The findings showed that approximately 19% of these patients experienced ILD recurrence, typically approximately 40 days after they had started cancer-directed therapy again. The most common rechallenge therapy for these patients was cytotoxic drugs, which are powerful and used to kill cancer cells.
The results of this study highlight the risk of ILD recurrence in patients with breast cancer who undergo cancer-directed therapy again. This insight is crucial for doctors and patients when deciding on cancer treatments, especially after a patient has already had ILD. This demonstrates the importance of careful planning and personalized treatment strategies to manage the risk of ILD while attempting to effectively control cancer. This study helps in understanding the trade-off between treating cancer to protect patients while not causing serious side effects such as ILD.