This 72-year-old female presents with a biopsy-proven adenocarcinoma of the sigmoid colon at 20 cm. the patient has been noted to have some bright red bleeding intermittently for approximately 8 months, initially presumable of a hemorrhoidal basis. she recently has had intensification of the rectal bleeding but no weight loss, anorexia, or obstructive pain. no significant diarrhea or constipation. some low back pain, probably unrelated. recent colonoscopy by dr. scoma revealed a large sessile (attached by a broad base) polyp, which was partially excised at the 20 cm level, showing infiltrating adenocarcinoma at the base. the patient is to enter the hospital at this time, after home antibiotic and mechanical bowel prep, to undergo sigmoid colectomy and possible further resection. what procedure did she have recently that diagnosed her condition?