[A Case of Interstitial Pneumonitis Induced by Lapatinib plus Letrozole]
Daigo Yamamoto1, Chizuko Yamamoto, Mitsuo Yamamoto
1Dept. of Surgery, Kansai Medical University Medical Center.
Abstract:
Lapatinib is an orally bioavailable dual inhibitor of the intracellular domain of both the HER2 protein and the epidermal growth factor receptor. This dual inhibitor can effectively prevent the downstream signal transduction initiated by a tyrosine kinase, thereby reducing the proliferation rate of tumor cells. Lapatinib was demonstrated to be beneficial in patients with HER2-positive locally advanced and metastatic breast cancer. We present here a case of interstitial pneumonitis that occurred after lapatinib treatment. A 79-year-old woman was diagnosed with Stage III infiltrating ductal carcinoma of the right breast. She underwent a modified radical mastectomy in January 2009, followed by anthracycline and paclitaxel plus trastuzumab administration. In November 2015, lung metastatic disease was detected. Therefore, lapatinib plus letrozole administration was initiated. Twelve days after starting treatment, she developed severe eruptions along with dyspnea. Radiography and a CT scan showed a diffuse ground glass shadow. Both her symptoms and the radiographic findings improved dramatically after the start of high-dose corticosteroid therapy. Clinicians should be aware that lapatinib has the potential to cause lung injury.
Insights
Lapatinib, a dual inhibitor for HER2-positive breast cancer, can cause lung injury. A case study highlights interstitial pneumonitis as a potential side effect requiring clinical awareness.
Area of Science:
- Oncology
- Pharmacology
Background:
- Lapatinib is a dual tyrosine kinase inhibitor targeting HER2 and EGFR.
- It is used for HER2-positive advanced and metastatic breast cancer.
- Lapatinib reduces tumor cell proliferation by inhibiting downstream signaling.
Observation:
- A 79-year-old woman with metastatic breast cancer developed lung issues after starting lapatinib and letrozole.
- Symptoms included severe eruptions and dyspnea, appearing 12 days after treatment initiation.
- Radiography and CT scans revealed diffuse ground glass opacity.
Findings:
- The patient experienced interstitial pneumonitis.
- Symptoms and imaging findings resolved with high-dose corticosteroid therapy.
- This suggests a potential causal link between lapatinib and drug-induced lung injury.
Implications:
- Clinicians must recognize lapatinib's potential for causing lung injury.
- Early detection and management of lapatinib-induced pneumonitis are crucial.
- This case underscores the importance of monitoring for pulmonary adverse events during lapatinib therapy.
