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.