Risultati preliminari di un protocollo di radioterapia preoperatoria nella cura dei tumori del retto

From March, 1988, to October, 1993, fifty-six consecutive patients with rectal adenocarcinoma in clinical stage T3NxM0, underwent preoperative radiation therapy at the "Casa Sollievo della Sofferenza" Hospital of San Giovanni Rotondo (Italy). The patients were treated with the four-field technique with 6 to 8 MV X photons on the pelvis. The dose given was 36 Gy in 12 fractions of 3 Gy each. Surgery was performed 2-3 weeks after completion of radiotherapy. Six patients were excluded from this study for metastastic involvement of the liver found at surgery. 48% of 50 assessable patients underwent abdominoperineal resection and 52% anterior resection. 68% of patients were in pathologic stage pT0-3 pN0 and 32% in pT0-3 pN1-2. Metastatic nodes were found in 16 patients (32%) (11 pN1 and 5 pN2). 4% of patients achieved a complete response. The follow-up ranged 24 to 91 months (mean: 46 months). None of the 50 patients died during the postoperative period and the specific morbidity was 26%. Side-effects, requiring surgery, were found in 4% of patients (1 retroperitoneal fibrosis and 1 small bowel occlusion). The incidence of local relapse was 8%. The overall survival at 5 years, in all stages, calculated with the Kaplan and Meyer method, was 76.5%. The disease-free survival rate was 81.1% in all stages: 94.1% in pT0-3 pN0 patients and 54.1% in pT0-3 pN1-2 patients. The disease-free survival rate related to nodal involvement was 72.7% in pN1 patients and 20% in pN2 patients. Our experience confirms the effectiveness of preoperative radiation therapy to improve local control in rectal cancer patients. In the future, it will be useful to assess the impact on prognosis of the schedules using chemotherapy, different fractionation of radiotherapy, delayed surgery and biological predictors of response to irradiation.