The Basis of Rectal Cancer
The rectum is defined as the last 16 cm of the intestine, which directly borders onto the anus. The section of the intestine found immediately prior to the rectum is the colon (large intestine).
Malignancies emanating from the mucosae of these regions of the intestine are termed as colorectal cancers and account for some 95 - 98% of all malignant diseases of the large intestine and rectum. They constitute the second most common cause of cancer in general in both males and females in Germany. The annual number of new cases is estimated at 35000 for both sexes, respectively. Intestinal cancer is also the second most frequent tumour related cause of death for both sexes, with nearly 15000 deaths annually.
Although the usage of the term colon cancer is often to imply all cancers of the rectum and colon, the two regions differ to a large extent, amongst other things, in the embryology, therapy, prognosis, and frequency of the tumour site. For example, advanced stage rectum cancer has a much worse prognosis. Although the colon is significantly longer than the rectum, some 35% of all colorectal tumours are located in the rectum. These days, their treatment differs fundamentally from that of colon cancers.
While the chosen method of treatment was surgery followed up with radiotherapy and combined chemotherapy (so called radio/chemotherapy or RT/CT) up until a few years ago, numerous experiments have revealed that some patients benefit from RT/CT prior to actual surgery. This so called neoadjuvant or pre-operative RT/CT is currently recommended in Germany as the therapeutic standard for local advanced tumours of the lower and middle thirds of the rectum.
Currently, pre-operative treatment of any kind is neither successful for early stage patients nor for those at an extremely advanced stage of disease.
In practice, this means that patients are fully examined and assessed after having been diagnosed with rectal cancer in the forefront of any treatment. During this examination, also known as staging, data concerning the exact height of the tumour in the rectum, its extent, as well as the presence of metastases are collected.
Appropriate to the disease stage, treatment is then initiated, which is carried out where possible within the framework of clinical studies. The great advantage of such studies is standardized patient treatment, which not only facilitates comparison of the results, but also guarantees the patient being treated according to a pre-specified protocol. At the present time, patients with local advanced rectal cancer of the lower or middle third of the rectum are treated within the framework of the CAO/ARO/AIO-04 Study. In this study, two different chemotherapy regimes are being investigated: on the one hand treatment with 5-fluorouracil (5-FU) on its own and on the other hand in combination with oxaliplatin. In both cases, treatment is supplemented with radiotherapy.
