A carcinoid tumour is a special type of tumour arising from what are called APUD cells in the intestines. It may be benign or malignant. On occasions if incompletely removed or if malignant, it can recur. However, it does not follow that your husbands symptoms after surgery are due to recurrence since symptoms such as occasional constipation and mild pain may be nonspecific and not related to previous disease. However, he would need periodic review with rectal ultrasound and CT and other biochemical investigations depending on whether the carcinoid was reported as benign or malignant. If there is recurrence it has to be dealt with appropriately - with surgery plus chemotherapy.