1) Exclude the study if it consists of the following combined drug therapy:Alectinib versus Crizotinib combined with other ALK inhibitors.Alectinib versus Crizotinib combined with chemotherapy.Alectinib versus Crizotinib combined with Immunotherapy.Alectinib versus Crizotinib combined with radiotherapy.2) Exclude if the study does not compare Alectinib versus Crizotinib in ALK-positive NSCLC. Here, ALK is linked to non-small cell lung carcinoma.