Malignant Neoplasm

In 2007 I had a malignant neoplasm removed that was hidden deep inside my face between the eye and nose. I originally thought that a tiny speck on my nose was a repeat of a basal cell carcinoma (and so did my surgeon). I have had the most wonderful surgeon and I'm going to see him next week to resolve a question that I have. I have been having problems with depression that could be attributed to several life issues I have experienced (especially having cared for my mother who had Alzheimer's and died in September 2007. My surgery was in July. I am concerned, however, that maybe there are cells from my past tumor that have invaded my prefrontal cortex and might be a reason why I have depression. My behavior includes feeling like I have a short circuit between planning and action. I find myself getting into knots every time I am asked for the slightest favor. I've always been one upon whom others rely. Sometimes I drag myself to work. (I am a college professor.) I usually love my job. So, I have started with a counselor and am on two meds for the depression. Has anyone read, heard of, or experienced a change in behavior due to any kind of invasion to the prefrontal cortex? Is there something specific I should ask my surgeon?