Background and purpose: Preoperative radiochemotherapy (RCT) followed by curative surgery is a well-accepted therapeutic option in the treatment of advanced rectal cancer. Usually, the anal sphincter is located in the irradiation area of a preoperative RCT regime. The aim of this study is to evaluate the influence of preoperative RCT on anal sphincter function.
Patients and methods: Between 1994 and 2000, 102 patients with rectal cancer stage uT3/uT4 were analyzed. All patients underwent radiotherapy with 45 Gy (5 x 1.8 Gy) including two cycles of 5-fluorouracil (5-FU)/leucovorin (folinic acid) chemotherapy. 46 patients were treated additionally with up to five sessions of locoregional hyperthermia. The sphincter function was analyzed by perfusion manometry before preoperative therapy and 4 weeks after pretreatment had been finished. For statistics, the Wilcoxon signed rank test and Mann-Whitney U-test were used (SPSS 9.0 for Windows((R))).
Results: The mean value of all 102 patients showed a significant reduction of the mean maximum resting pressure from 97 to 89 mmHg (p = 0.02). For the mean maximal squeeze pressure no significant difference could be shown (178 vs. 176 mmHg). For patients with distal (</= 7.5 cm from anal verge) tumors the difference was highly significant (92 vs. 79 mmHg). Locoregional hyperthermia had no additional influence on sphincter function.
Conclusion: Preoperative RCT impairs sphincter function especially in patients with distal tumors. In addition, RCT could have a negative influence on the continence of patients who received sphincter-preserving surgery.