A Case of Disappearance of Rectal Cancer during Neoadjuvant Chemotherapy by 5-FU Continuous Systemic Infusion

The clinical course in a patient, whose rectal cancer disappeared during continuous systemic infusion of 5-FU, is described herewith. A 70-year-old woman consulted our hospital complaining of anal bleeding. Colonofiberscopy revealed a rectal cancer of 4 cm in diameter. The tumor had a very short stalk under its large head. Endoscopic ultrasonographic examination indicated that the submucosa was interrupted by low echogenic tumor tissue. A biopsy confirmed the existence of a moderately differentiated adenocarcinoma. After 3 week of continuous and systemic administration of 5-FU in a low doses (250 mg / day for 1 week and 375 mg / day for 2 weeks), the patient underwent low anterior resection of the rectum. The tumor was no longer detectable within the surgical specimen. Only an ulcerative lesion about 1 cm in diameter was found. The histological examination failed to show carcinomatous cells. Only granulative tissue with a massive infiltration of inflammatory cells and regenerating glands of partially atypic form was found. These findings suggest that the stalk of the tumor underwent necrosis and that the head of the tumor was discharged with the stool before the operation. The low dose continuous systemic infusion of 5-FU seems to be one of the beneficial regimens of neoadjuvant chemotherapy for rectal cancer.