Abstract: The present invention relates to system, device, and method utilizing cryosurgery to treat a tumor of the breast. More particularly, the present invention relates to treating a breast tumor by inserting into a breast, at a selected site known to be a locus of a tumor, an introducer having at least one access port, operating a biopsy needle through an access port to perform a biopsy of tissues at the selected site, and operating a cryoprobe through an access port to cool body tissues to cryoablation temperatures, thereby ablating or downsizing the tumor. The present invention further relates to use of cryoablation to downsize a large malignant tumor as pre-operative preparation for conventional excision surgery.