RESUMO
PURPOSE: The potential advantage of high-dose preoperative radiotherapy to increase tumor response and improve the chance of sphincter preservation for low rectal cancer remains controversial. The aim of this trial was to evaluate the role of escalating the dose of preoperative radiation to increase sphincter-saving procedures. PATIENTS AND METHODS: Patients with rectal carcinoma located in the lower rectum, staged T2 or T3, Nx, or M0 with endorectal sonography, and not involving more than two-thirds circumference, were randomly assigned to one of two groups: preoperative external-beam radiotherapy (EBRT; 39 Gy in 13 fractions over 17 days) versus the same EBRT with boost (85 Gy in three fractions) using endocavitary contact x-ray. RESULTS: Between 1996 and 2001, 88 patients were enrolled onto the study. A significant improvement was seen in favor of the contact x-ray boost for complete clinical response (24% v 2%) and for a complete or near-complete sterilization of the operative specimen (57% v 34%). A significant increase in sphincter preservation was observed in the boost group (76% v 44%; P =.004). At a median follow-up of 35 months, there was no difference in morbidity, local relapse, and 2-year overall survival. CONCLUSION: A dose escalation with endocavitary irradiation provides increased tumor response and sphincter preservation with no detrimental effect on treatment toxicity and early clinical outcome.
