ABSTRACT
PURPOSE: To investigate the effect and feasibility of concurrent radiation and chemotherapy combined with endorectal brachytherapy in T3 rectal cancer with complete pathologic remission as end point. METHODS AND MATERIALS: The study included 50 patients with rectal adenocarcinoma. All patients had T3 tumor with a circumferential margin 0-5 mm on a magnetic resonance imaging scan. The radiotherapy was delivered by a technique including two planning target volumes. Clinical target volume 1 (CTV1) received 60 Gy/30 fractions, and CTV2 received 48.6 Gy/27 fractions. The tumor dose was raised to 65 Gy with endorectal brachytherapy 5 Gy/1 fraction to the tumor bed. On treatment days, the patients received uracil and tegafur 300 mg/m2 concurrently with radiotherapy. RESULTS: Forty-eight patients underwent operation. Histopathologic tumor regression was assessed by the Tumor Regression Grade (TRG) system. TRG1 was recorded in 27% of the patients, and a further 27% were classified as TRG2. TRG3 was found in 40%, and 6% had TRG4. The toxicity was low. CONCLUSION: The results indicate that high-dose radiation with concurrent chemotherapy and endorectal brachytherapy is feasible with a high rate of complete response, but further trials are needed to define its possible role as treatment option.
