The Impact of Probiotic on Survival and Treatment Response in Metastatic Non-small Cell Lung Cancer Patients

Inclusion Criteria: * Volunteering to participate in the study. * Histologically confirmed diagnosis of Non-Small Cell Lung Cancer (NSCLC). * Patients must be in an advanced stage (incurable with surgery or radiotherapy) or have metastatic disease (Stage IV). * Male or female patients aged \>18 years. * Eastern Cooperative Oncology Group (ECOG) Performance Status less than 2. * Laboratory findings must confirm adequate bone marrow function, indicated by: White Blood Cell (WBC) count \> 2,000/mm³, Neutrophil count \> 1,500/mm³,Platelet count \> 100,000/mm³ Exclusion Criteria: * Previously received treatment with any of the following antibody blockers: anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137, or anti-CTLA-4. * Currently taking probiotic supplements or consuming probiotic bacteria-supported yogurt and similar food supplements. * Antibiotic utilization within the past month * Active interstitial lung disease or a history of interstitial lung disease requiring systemic steroid treatment. * A condition requiring systemic corticosteroids (greater than 10 mg of prednisone daily or equivalent) or who have received immunosuppressive treatment within 14 days prior to the first dose of the study. * Presence of uncontrolled adrenal insufficiency. * Pregnancy or breastfeeding. * Severe congestive heart failure (Class III or higher according to the New York Heart Association Functional Classification) or a history of myocarditis. * Uncontrolled cardiac arrhythmia that developed within six months prior to the start of the study.