Introduction

Rectal cancer (RC) accounts for about 30% of all large bowel tumours and is effectively treated by radical surgery, which may also preserve anorectal function when tumours are small, exophytic, mobile and located in the proximal rectum. As stated by the National Institutes of Health Consensus Conference in the United States in 1990 [1], combined treatments including radical surgery and radiation therapy with or without chemotherapy may improve both local control as well as survival when the disease is staged as locally advanced (stages II-III RC), is located to the distal rectum, has poor mobility or deep mucosal ulceration with circumferential bowel wall infiltration and lymph node involvement. Recurrence rates after surgical treatment of RC range from less than 5% to more than 30% and they are probably related to the surgeon's experience and skills, patient selection and different definitions of local failure. A modern concept for the surgical oncologist is the importance of a sharp dissection of the entire mesorectum in patients with potentially curable middle to lower RC, as suggested by Heald [2], who has performed this kind of surgery without any adjuvant treatment in a series of 115 patients reporting, at a mean follow-up of 4.2 years, very low recurrences which were only detected in the pelvis (2.6%) and not at the anastomosis. Circumferential margin is an important factor determining recurrence during potentially curative surgery and it may be predicted by magnetic resonance imaging (MRI) findings while assessing the mesorectal fascia. According to these points, radiation therapy may probably be omitted when surgery without adjuvant treatments is performed by teams who report less than 5% local recurrence rates at five years. On the other hand, a meta-analysis of all randomised trials showed that neoadjuvant are more effective than adjuvant treatments for both reducing local failure rates as well as improving cancer-specific survival [3]. The Dutch trial [4] randomised patients with clinically resectable RC to surgery alone by total mesorectal excision (TME), or short-course radiation followed by TME. In this trial the TME procedures and the pathological analysis of the specimens were standardised to limit the bias due to surgical expertise. While there were no significant differences in overall survivals, local recurrence rates were decreased in the group who received neoadjuvant treatment (12% vs. 6% at five years) [5]. Based on the results of the recently completed German Trial [6], patients with T3 and/or N1-2 RC should receive pre-operative combined modality therapy and undergo TME with adequate nodal dissection. The potential advantages of neoadjuvant therapy include earlier onset, increased tumour radio sensibility, decreased radiation complications, decreased local recurrence rates due to tumour seeding during the surgical procedure, and, probably, increased feasibility of performing sphincter-sparing surgery. The primary disadvantages of neoadjuvant therapy are the absence of a pretreatment pathological classification with a risk of overtreating small tumours as well as the risk of understaging lymph node status. Lymph node staging in patients who undergo pre-operative radiotherapy alone or in combination with chemotherapy should be interpreted with caution because the clinical relevance of the number of nodes involved and the pathologic stage are not completely evaluated by clinical studies. For example, a large study reported that T3N0 RC patients, who had undergone surgery combined with post-operative radio and/or chemotherapy, had a poor prognosis if few lymph nodes had been evaluated by the pathologist [7,8]. MRI advances have improved the selection of patients with stage T2-T3 disease, thus reducing overtreatment of pre-operative radio- and chemotherapy. Advanced MRI with particular contrast medium will improve accuracy in staging the lymph node metastases as well as patient pre-operative selection for aggressive chemoradiotherapy regimens. As RC represents not a uniform entity but a wide spectrum of diseases, it is extremely important to classify and stage RC patients correctly because the application of radiotherapy principles requires information including concerning tumour biology,

Fig. 1. RC radiation therapy and patient selection

Fig. 1. RC radiation therapy and patient selection surgical procedures and expertise, anatomy of the pelvis, and RC failure patterns. In conclusion, we think that the modern approach of radiation oncology is to select the best patient for the best treatment. After this overview and as depicted in Fig. 1, we will briefly describe RC radiation therapy dealing with patient selection and protocols as performed at our institution.

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