Clinical Significance of Tumor Disappearance Ratio in EGFR-Mutant Lung Adenocarcinoma with Brain Metastases: A Case Series

Background Among lung cancer subtypes, lung adenocarcinoma is the most frequently diagnosed histologic form and is commonly impacted by EGFR mutations. Tumor disappearance ratio (TDR) has been proposed as a prognostic marker. A decreased TDR tends to be linked with more invasive pathological characteristics, including pleural and lymphovascular involvement and advanced tumor stage. Notably, chest CT findings in patients with TDR ≤ 75% often revealed micropapillary or solid patterns that corresponded with higher invasiveness. Case presentation: We reported three cases of Lung Adenocarcinoma with TDR < 75% and CNS Metastases. All of the patient’s first CXR only shows consolidation but Chest CT and Histopathology confirm with Lung Adenocarcinoma EGFR mutation. All of those patients had neurology complaints as first symptoms rather than respiratory symptoms. First, Female 69 years old complained of chronic headache, then the patient performed brain MRI results show the cerebellar metastatic process. After that, the patient underwent chest CT show lung mass with TDR 11%. Then the patient has lower respiratory tract infection and sepsis with WBC 14.710 and procalcitonin 7,76 ng/ml. The patient died because of sepsis after 7 days of treatment. Second, Male 49 years old with right hemianesthesia. The patient complained of numbness and tingling of his right limb, the patient performed a brain MRI and show as brain metastasis. After that, the patient underwent chest CT show lung mass with TDR 33%. Then patient underwent for chemotherapy. After 10 days, patient has dyspnea and CXR show right pleural effusion. Then patient had thoracocentesis but respiratory failure still existed and patient died. Last case, Male 48 years old with a seizure, whole body spasm and eyes glancing upwards. First, patient was diagnosed as meningioma and performed brain surgery. The histopathology result show that metastatic adenocarcinoma from the lung. The patient underwent chest CT show lung mass with TDR 33%. Then patient underwent chemotherapy and radiotherapy, the patient had success for the CT evaluation as a partial response. Conclusion Low TDR value correlate with a vascular invasion that present as Brain Metastases in Lung Adenocarcinoma with EGFR mutation.