Chances and developments of neoadjuvant and adjuvant therapies in rectal cancer

The objective of adjuvant/neoadjuvant therapy of rectal cancer is the reduction of the rate of local recurrences and distant metastases compared to surgery alone. Until this year postoperative radiochemotherapy was the standard treatment for patients with UICC stage II and III tumors. Based on randomized trials, a change of the treatment strategy is necessary. Trials performed in Sweden and The Netherlands showed that preoperative radiotherapy with 5 x 5 Gy improved local control compared to surgery alone. The recently published German AIO/CAO/ARO study found that neoadjuvant 5-FU-based radiochemotherapy improved local control compared to postoperative radiochemotherapy and reduced acute and late toxicity. Moreover, compared to preoperative radiotherapy with 5 x 5 Gy neoadjuvant radiochemotherapy possibly enables sphincter-preserving therapy. Nevertheless, the consistently high rate of distant metastases of 30 - 40% is not satisfactory at all. The intensification of neoadjuvant radoiochemotherapy with oxaliplatin or CPT-11 doubles the rates of pathologically complete response rates. Whether or not this strategy together with intensified postoperative chemotherapy may also reduce the rate of distant metastases will be investigated in planned randomized studies.