[Treatment of rectal cancer]

In patients with stage II/III rectal cancer, primary neoadjuvant radiochemotherapy (RCT) with infusional 5-fluorouracil (5-FU) is a well-established treatment because it improves local control of the tumor. The high rate of distant metastases continues to be a problem. Preliminary data from a phase III trial with cabecitabine versus infusional 5-FU show better lymph node down-staging with neoadjuvant capecitabine therapy. Adding oxaliplatin, by contrast, did not significantly improve the pathophysiological complete remission (pCR) rates in 2 current phase III trials. Whether it may still have an effect on the long-term prognosis of the patients remains to be seen. Extending neoadjuvant systemic RCT with bevacizumab is an approach that has shown promising results in phase I/II trials. By contrast, adding cetuximab to RCT did not result in an improvement in pCR rates in most studies published to date. The role of adjuvant chemotherapy is controversial. The current S3 guideline recommends adjuvant chemotherapy after neoadjuvant RCT independently of tumor stage--in other words, also in patients with complete remission or UICC (Union internationale contre le cancer) stage I/II disease. More recent studies are looking at induction chemotherapy before neoadjuvant RCT and at the use of chemotherapy alone (without RCT) in suitable patients. A new surgical technique is extended posterior perineal resection with gluteus maximus flap reconstruction of the pelvic floor (Holm's cylindrical resection), which results in significantly more circumferential resection margin (CRM)--negative tumors and significantly fewer intraoperative perforations.