My dad is being treated for small cell lung cancer. He was diagnosed June 2016. He went through chemo this summer/fall, and now is undergoing radiation therapy on his chest and brain. We are praying for good results on his next scans. He mentions he feels a little unbalanced when walking. He told his doctor this today, and his doctor said it may be a side effect of the radiation. Has anyone else experienced being unbalanced while undergoing radiation? I'm a little concerned.