Folic Acid Supplement Versus Placebo for Treating Mucositis Adverse Events in Metastatic Renal Cell Carcinoma Patients Receiving Targeted Therapy

This study tests whether taking folic acid (a B vitamin supplement) can reduce painful mouth sores (mucositis) — a common and uncomfortable side effect — in patients with advanced kidney cancer who are receiving targeted therapy drugs. **You may be eligible if...** - You have inoperable, locally advanced, or metastatic (spread) kidney cancer confirmed by biopsy - You are currently receiving targeted therapy (such as TKI, mTOR inhibitor, or immunotherapy) and experiencing moderate to severe mouth sores (grade 2 or higher on the CTCAE scale) - You are 18 years of age or older - You are willing to follow the study protocol **You may NOT be eligible if...** - You are pregnant (unless pregnancy can be excluded by other means, such as menopause or prior surgery) - You are not currently experiencing mouth sores from your treatment - You are unwilling or unable to comply with study requirements Talk to your doctor to see if this trial is right for you.