[en] High-dose-rate intraluminal brachytherapy (HDRIBT) is the effective treatment modality for esophageal cancer. In October 1986, a Phase I-II study was initiated to evaluate the effect of preoperative HDRIBT in rectal cancer. Fifty-two patients, enrolled until December 1990, have been analyzed to describe the relevant technical aspects and toxicity. HDRIBT was performed with remote afterloader. Shell was used for immobilization of the patient during HDRIBT. New outer tube, made of silicone, was easily fixed to the patient. Fractions of HDRIBT was one to five and the total dosage was escalated from 16 Gy to 80 Gy. The effective response of local tumor was achieved in the cases irradiated with 30 Gy or more. Local recurrence and distant metastasis after surgery were detected in three and four cases, respectively. Life threatening toxicity (G₃ complication) was detected in one case (1.9%). Other severe toxic events requiring surgical intervention (G₂ complication) were detected in five cases (9.6%). After the life threatening toxicity, most of patients were treated with total dosage of 30 Gy in two fractions. This experience supports HDRIBT as a feasible preoperative treatment modality to be used in the management of rectal cancer. These results deserve further investigation and confirmation trials. (author)