[Tumor downstaging through preoperative chemoradiotherapy in locally advanced rectal cancer].
OBJECTIVE: To evaluate the impact of preoperative chemoradiotherapy on patients with locally advanced rectal cancer by clinical and pathological characteristics. METHODS: From July 1994 to May 1995, 36 patients with locally advanced rectal cancer were treated. Pathology: adenocarcinoma 27, mucinous adenocarcinoma 7 and ductal adenocarcinoma 6. The protocol was carried out in sequence of chemo-->radio-->surgery-->chemotherapy. The treatment began with preoperative chemotherapy with folinic acid 50 mg followed by 5-FU bolus of 300 mg/m2 given for two cycles on d1-5 and d22-26 before irradiation. Radiation therapy was delivered to a dose of 45 Gy, 1.8 Gy per fraction, 5 days a week. Surgery was done 4-6 weeks after this preoperative treatments. Another 2 to 4 cycles of chemotherapy were added 2 to 4 weeks after operation. Twenty-one patients were treated by Dixon's operation, 14 patients by Mile's operation and 1 by local tumorectomy through the rectum. Radical operation was performed in 29 patients and palliative resection was done in 7 patients. RESULTS: Grade III hematological toxicity was observed in only 2(5.6%) patients. No patient had grade III or IV acute toxicity in the gastrointestinal, skin or urological systems. All patients underwent surgery. The perioperative morbidity rate was 13.8% with no mortality or late toxicity. As a result of this preoperative management, the tumor was reduced by an average of 28.0%, with a complete pathological response in 4(11.1%) patients. In 28 CR + PR (77.8%) patients, a downstaging in 19(52.8%) patients was observed. Sixty percent of positive lymph nodes as assessed by transrectal ultrasonography before therapy became pathologically negative postoperatively, with the frequency of lymph node metastasis decreased by 46.0%(83.0% to 37.0%). CONCLUSION: Preoperative radiochemotherapy is proved as a safe method with a tolerable toxicity. Complete pathological response, shrinkage of the primary tumor and decrease in lymph node metastasis are observed after preoperative radiochemotherapeutic regimen. An overall benefit of downstaging the primary tumor and a greatly enhanced effect of surgery is enjoyed by the patients.