... Situ; extending to the deep margin: My Dr. says that "extending to the deep margin" means that abnormal cells were found at the bottom of the biopsy sample. Her treatment plan is electrodessication and cautery, which destroys tissue and does not allow for re-biopsy.

My question(s): If cancer cells were found at the bottom of the sample, how do we know how deep they actually are? And not knowing, how can it be classified as "in situ"?

I'm 65, female, blonde/blue/ fair-skinned with a ton of freckles, w/ a history of sunburn and a number of keratosis. Previously have had basal cell removed and melanoma (superficial spreading type) removed. History of HPV as well. My brother also has a history of SCC.

The Dr. says they can treat with excision/re-biopsy; it's my choice. Am I being overly cautious to want that?