Evaluate the size of the primary tumor and the risk of obstruction before treatment, and use laxatives if necessary to keep the bowel openPay attention to the use of antiemetic drugs during treatment. Long-acting 5-HT antagonists are not recommended for patients at a high risk of obstructionDeal with difficulties in defecation in timeStrengthen dietary guidanceIf intestinal obstruction occurs during treatment and conservative medical treatment is ineffective, preventive stoma surgery could be considered. The gene discussed is HTR5A; the disease is intestinal obstruction.