Adjuvant postoperative radiotherapy in rectal cancer: 148 cases treated at Florence University with 8 years median follow-up

Background and purpose. To analyse the outcome, the treatment related side effects, the prognostic significance of clinical parameters in a group of patients with rectal cancer receiving postoperative radiotherapy after radical resection. Materials and methods. From 1980 to 1990 148 consecutive patients with rectal carcinoma stage B2-B3 or Cl-C2-C3 were treated with postoperative radiotherapy after radical surgery. All patients received 50 Gy in 25 sessions in 5 weeks. In 42 a 'flash' dose of 5 Gy was also given within 24 h before surgery. Median follow up was 8.1 years. Results. At 5 years the overall survival was 54%, the determined (cancer specific) survival 61%, the local recurrence-free survival 88%. The influence of stage, histotype, distance from anal margin, type of surgery, number of involved nodes and flash dose were analysed. Overall and determined survival and distant metastasis rate were significantly influenced (P < 0.005) by the pathological stage. Patients with more than 3 involved nodes presented a significantly lower determined survival (P < 0.001) and a higher distant relapse rate (P < 0.005) than those with 3 or less involved nodes, A higher determined survival (P < 0.01) was also found in patients receiving the preoperative 'flash'; this group was however unbalanced in respect to the relative number of cases with 3 or less involved nodes. The incidence of major side effects requiring surgery or hospitalization for medical treatment was 35% before 1985 and 12% thereafter. The systematic use of small bowel visualization during simulation and the discontinuation of the flash dose were the main modifications introduced in the second period. As a consequence of the small bowel visualization the size of lateral fields was slightly reduced and some patients were excluded from the treatment. Conclusions. Value of postoperative radiotherapy to decrease the incidence of local recurrence was confirmed in this retrospective study; the incidence of side effects was however considerable and did not support the addition of chemotherapy as advised try the NIH consensus meeting. Our policy was therefore moved to preoperative irradiation whose combination with chemotherapy was recently reported to be better tolerated and highly effective.