Pre Operative Radiotherapy

In our department pre-operative radiotherapy is the standard treatment for stage 2-3 rectal RC and, as reported before, an increasing body of data suggests the superiority of pre-operative radiotherapy combined with chemotherapy in terms of local control, disease-free survival and reduction of bowel toxicities. There are two types of pre-operative radiotherapy: fractionated radiotherapy and short course. Short-course pre-operative radiotherapy is delivered one week before surgery in 5 daily fractions of 5 Gy without any chemotherapy. Pre-operative frac-tioned radiotherapy is delivered in a period longer than 5 weeks (daily doses of 1.8-2 Gy for total doses of 45-50 Gy), usually with a 5-FU schedule, and is followed by surgery which is performed 4-6 weeks after in order to restore the acute damage and as well as to reduce tumour volume. Probably the most important argument in favour of pre-operative radiation therapy is tumour regression, which may improve the likelihood of a successful resection with free margins. The possibilities of preserving the sphincter are increased for regressing tumours arising in the distal rectum. From this point of view, short-course radiation offers low tumour reduction probabilities due to the surgery timing. The choice of treatment is fractionated radiotherapy because it offers a high probability of sphincter preservation. After pre-operative chemo- and radiotherapy, a pathologic complete response rate of 10-25% has been reported as well as a tumour downstaging rate of 40-80% with both improved local control and survival [12, 13]. For this reason, different institutions, including our department, have routinely used some form of dose intensification and the addition of chemotherapeutical agents such as oxali-platin in order to increase the pathological complete response rate as well as local control and survival. By using a novel, custom-made, modified belly board, we investigated the effects of reduced radiations on the small bowel as well as their effects on volume and median dose. Using a four-field box technique, the mean dose of the small bowel of patients treated on our belly board was significant lower than with the standard technique [14]. We have also investigated the possibility with this bowel device of an escalation of the radiation dose. Between October 1998 and December 2002,109 patients with primary RC (T3-T4) underwent pre-operative radioche-motherapy plus hyperthermia with escalation of the radiation dose. The median total dose in this series was delivered and escalated as follows: 54 Gy in the first 21 patients, 56 Gy in the second group of 41 patients, 62 Gy in the third group of 22 patients and 64 Gy in the fourth group of 25 patients. The treatment was well tolerated without any significant side effect. Six patients with a clinical complete response refused surgery and were submitted to an intensive surveillance protocol. The pathological complete response rate was 30% and the local recurrence rate was 2%, and also the survival was 76% after mean follow-up of 4 years. Of the 6 patients that refused surgery, 1 patient died from metastatic disease without evidence of local recurrence, while the other 5 patients are still alive without disease. A multivariate analysis showed that radiation doses >60 Gy and tumour length less than 3 cm were related to a higher rate of complete pathological responses. In this experience, dose escalation may have contributed to an increase of the pathological complete response rate and to a better outcome for patients refusing surgery [15]. A valid criticism of this kind of study is that we do not know how applicable the staging system is for patients who have undergone pre-opera-tive radiochemotherapy. Probably, post-treatment pathologic findings represent a composite situation of stage of the tumour and its response to pre-oper-ative therapy and pathological complete responders may simply represent the quota of patients with less aggressive disease and/or with a disease that strongly responds to the treatment. In the future, the use of more precise pre-operative staging systems will allow evaluation of how pre-operative radiochemo-downstaging may impact patient survival. Of much interest is the report of overall long-term results of stage 0 RC following neoadjuvant chemoradiation that compared operative and non-operative treatment [16]. In this report, after radiochemotherapy patients with incomplete clinical response treated by surgery resulting in stage pT0 were compared to patients with complete clinical response not treated with surgery: five-year overall and disease-free survival rates were 88 and 83%, respectively, in the resection group and 100 and 92% in the observation group. The Authors concluded that stage 0 RC disease after radiochemotherapy is associated with excellent long-term results irrespective of surgical resection.

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