Early detection of drug-induced interstitial lung disease using an electronic patient-reported outcome system: a report of two cases

Drug-induced interstitial lung disease (DILD) is an adverse event associated with the use of various anticancer drugs. Although DILD is rare, it is a serious complication that can lead to treatment interruption and, in some cases, life-threatening outcomes. The early detection of DILD requires careful monitoring of subjective symptoms, regular computed tomography (CT) scans, and biomarker assessments. We present two cases in which electronic patient-reported monitoring by a pharmacist, utilizing an electronic patient-reported outcome (ePRO) application, enabled the early detection of DILD in patients with breast cancer undergoing anthracycline-based adjuvant therapy and treatment for recurrence with everolimus (EVL) and exemestane (EXE). In the first case, a woman in her 50 s with early stage breast cancer received dose-dense epirubicin and cyclophosphamide (EC) therapy as adjuvant treatment following surgery. On day 14 of the second cycle, the ePRO flagged cough and fever symptoms. The following day, the patient's fever subsided, and chest X-rays showed no abnormal findings. The third cycle of dose-dense EC therapy was discontinued, and the patient was followed up. Monitoring with ePROs was continued, and on day 18, the patient developed a fever again and experienced worsening dyspnea, prompting a medical consultation. Chest CT confirmed the diagnosis of DILD, and steroid pulse therapy was initiated. In the second case, a woman in her 60 s with recurrent breast cancer underwent EVL + EXE. Between days 86 and 89, ePROs identified fever, fatigue, and cough, prompting the patient to consult a physician. A chest CT scan revealed grade 1 DILD, which led to the discontinuation of EVL therapy. These cases suggest that the application of ePRO is valuable for the early detection of DILD, potentially improving patient outcomes by allowing timely intervention.