Case report: NSCLC with pulmonary embolism after treatment with almonertinib
Authors: Han Zelu , Liu Lingshuang , Jiang Yi , Gao Xintong 
Published: May 2024

Rationale:
Almonertinib is the first independently developed third generation epidermal growth factor receptor tyrosine kinase inhibitors in China. It can be used not only for epidermal growth factor receptor (EGFR) sensitive mutation patients but also for T790M (+) resistant patients, and has better safety and survivability compared to the first and second generation EGFR-TKIs. The previous literature and case studies have reported significant treatment-related adverse reactions in non-small cell lung cancers patients treated with almonertinib, including elevated blood creatine phosphatase, prolonged cardiac QT interval, altered myocardial contractility, interstitial lung disease, eye disease, and hematological events. But there are few individual reports of pulmonary embolism events.

Patient concerns:
A 55-year-old female with no history of smoking visited a local hospital with mild cough and lower sacrococcygeal pain without obvious cause.

Diagnosis:
She was diagnosed with right lung adenocarcinoma with multiple bone metastases (T2bN1M1c, stage IVB) after image and histological examination, with EGFR 21 exon L858R sensitive mutation.

Interventions:
She initially underwent surgical treatment due to the discovery of a sacral tumor, and the pathology of the surgery indicated metastatic lung adenocarcinoma. Genetic testing results showed EGFR 21 exon L858R sensitive mutation. Combined with positron emission tomography/computed tomography imaging results and sacral tumor surgical pathology results, it was considered that the patient had lung adenocarcinoma with multiple bone metastases. Treatment plan: targeted treatment with almonertinib which is the third-generation EGFR-TKIs. After only 1 month of targeted treatment, chest enhanced computed tomography revealed pulmonary embolism imaging, combined with coagulation indicators, considering pulmonary embolism. As the thromboembolic site is located at the end of the pulmonary artery branch and imaging shows that tumor lesions are stable. Consider continuing targeted treatment with almonertinib and adjuvant oral anticoagulant therapy with rivaroxaban for treatment.

Outcomes:
Two months later, the patient’s condition was followed up and it was found that the imaging manifestations of pulmonary embolism disappeared, but the coagulation indicators remained in a hypercoagulable state. The patient’s treatment plan remained unchanged, and the patient was hospitalized for follow-up every 6 to 8 weeks to closely observe changes in the condition.

Lessons:
There are many reasons for the occurrence of hypercoagulable blood in tumor patients, and there are very few reports of treatment-related pulmonary embolism events in patients who are treated with almonertinib targeted therapy. It is particularly important to determine whether the hypercoagulable blood in such patients is related to targeted therapy drugs in clinical practice, as this will affect the clinical benefits of patients in epidermal growth factor receptor tyrosine kinase inhibitors treatment and the clinical indicators which need to pay more attention in follow-up observation, to avoid serious pulmonary embolism events and thus affect the patient’s survival status and quality of life.