Feasibility and Safety of Neoadjuvant Alectinib in Pulmonary Invasive Mucinous Adenocarcinoma with ALK Rearrangement: Case Report and Literature Review

BACKGROUND: Pulmonary invasive mucinous adenocarcinoma (IMA) is a rare variant of lung adenocarcinoma that rarely shows anaplastic lymphoma kinase (ALK) rearrangement. Alectinib (tyrosine kinase inhibitors) has been listed as category 1 recommendations for advanced ALK + NSCLC first-line therapy due to low toxicity and excellent efficacy, and its median progression-free survival is 34.8 months. Here, we report a case of a patient with ALK-rearranged lung IMA who showed favorable results to neoadjuvant alectinib. CASE: A 67-year-old man with no history of smoking was diagnosed with clinical stage as IIIB invasive mucinous adenocarcinoma based on clinical symptoms, chest CT and pathological findings. The anaplastic lymphoma kinase (ALK) fusion status was assessed by real-time PCR. After acquiring informed consent from the patient, we offered neoadjuvant alectinib at a dosage of 150 mg twice per day for three cycles (84 days), all lesions were undetectable on chest CT. Later, a thoracoscopic left lobectomy was performed. The postoperative pathological showed that a small amount of tumor cells remained, and the TNM stage was downstaged as T1aN0M0 IA. CONCLUSION: To our knowledge, this is the first case discussing the treatment of ALK-rearranged IMA of the lung with neoadjuvant alectinib. Alectinib is an effective ALK inhibitor, and in cases of lung adenocarcinoma with ALK rearrangement, alectinib treatment is a reasonable and priority option. Neoadjuvant alectinib may be clinically feasible and well tolerated in locally advanced NSCLC.