Phase II trial of preoperative 3D conformal radiotherapy, protracted venous infusion 5-fluorouracil, and weekly CPT-11, followed by surgery for ultrasound-staged T3 rectal cancer INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS Mehta, V. K., Cho, C., Ford, J. M., Jambalos, C., Poen, J., Koong, A., Lin, A., Bastidas, J. A., Young, H., Dunphy, E. P., Fisher, G. 2003; 55 (1): 132-137


CPT-11 sensitizes tumor cells to radiation and in combination therapy with 5-fluorouracil (5-FU) results in enhanced cytotoxicity to metastatic colorectal cancer. We report the results from a Phase II trial of preoperative radiotherapy (RT), CPT-11, and 5-FU for patients with ultrasound-staged T3 rectal cancer.Between April 1999 and August 2001, 32 patients (21 men, 11 women; median age 52 years, range 40-74) with biopsy-proven adenocarcinoma of the rectum were enrolled in the study. All patients underwent endorectal ultrasonography for staging (uT3N0 = 19; uT3N1 = 13; uT2N1 = 1). RT was prescribed to the draining lymph nodes (45 Gy in 1.8-Gy daily fractions) and tumor (50.4 Gy in 1.8-Gy daily fractions). Patients also received concurrent CPT-11 (50 mg/m(2), Days 1, 8, 15, and 22) and 5-FU (200 mg/m(2) daily, 7 d/wk, Days 1-33). Surgical resection was performed 6-10 weeks after completing chemoradiotherapy.Acute toxicity was frequently observed, and 18 patients (56%) required either a chemotherapy dose reduction or RT interruption of >3 days. One patient withdrew because of diarrhea and abdominal cramping (Grade III) after 10 days of treatment. Although no Grade IV toxicity was observed, Grade III diarrhea (n = 9, 28%), mucositis (n = 7, 21%), rectal sores (n = 7, 21%), abdominal cramping (n = 3, 9%) were noted. Of the 32 patients who underwent surgery, 12 had a complete pathologic response. Of the 32 patients, the disease of 23 (71%) was downstaged. The average length of hospitalization was between 5 and 12 days, with 1 patient staying 33 days. All patients were followed for disease-free survival.Although associated with frequent acute toxicity, the regimen is associated with significant tumor "downstaging." Additional patients and longer follow-up are necessary to define the role of this regimen fully.

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