Preoperative chemoradiotherapy for rectal cancer aims to decrease the local recurrence after the surgery. This measure adopted as a standard treatment internationally, however various symptoms caused by tumor could obstruct the preoperative treatment because 10-12 weeks are required before surgery. Among them, tumor pain caused by the invasion into surrounding tissue could be a big and prolonged problem during the treatment. In four cases of lower rectal cancer complaining of severe anal pain on first admission, we planned preoperative chemoradiotherapy with supporting treatment including administration of NSAIDs with or without opioids. After 4 weeks of chemoradiotherapy, all the patients could reduce of the amounts of the drugs. After preoperative chemotherapy as planned, all of them had curative surgery consecutively. The preoperative chemoradiotherapy for oncological safety must be carried out with special interest, care and treatment on the anal pain caused by rectal cancer.