[A case report of pathologically complete response with chemo-radiation for rectal cancer]

A 60-year-old female presented to a local hospital with a chief complaint of melena. Since she was found to have a neoplastic lesion in the rectum on endoscopy, she was referred to our hospital. Barium-enema examination and endoscopy showed a 5-cm type-2 lesion proximal to the dentate line, which was diagnosed by biopsy as a moderately differentiated adenocarcinoma. Pelvic CT and MRI showed lower rectal wall thickening with pararectal lymphadenopathy, and FDP-PET showed increased uptake in these sites. Under a diagnosis of cT3, cN2, M0, Stage III b cancer, she started with preoperative chemoradiotherapy, consisting of 50 Gy in 25 fractions and oral UFT (400 mg)/Uzel (75 mg). After therapy, the tumor showed only a 2-cm ulceration, and FDG-PET revealed no abnormal uptake. Under a diagnosis of cT1, cN0, M0, Stage I cancer, super-low anterior resection of the rectum with D2 lymphadenectomy was performed. Histopathological examination showed that cancer cells forming a glandular structure had completely disappeared, leaving a fibrous scar, consistent with a Grade 3 (pCR).