Investigation

Investigation

Abdominal examination Abdominal examination is normal in early cases. Occasionally , in patients with stenosing tumours at the rectosigmoid junction, signs of subacute large bowel obstruction may be present, with abdominal distension. If large volume liver metastases are present, an enlarged liver may be palpable along with other signs, such as cachexia. Occasionally , it may be possible to elicit ascites if there is widespread peritoneal dissemination. Rectal examination In many cases where the neoplasm is situated within 7–8 /uni00A0 cm of the anal verge it can be felt on digital rectal examination as an elevated, irregular and hard endoluminal mass. When the centre ulcerates, a shallow depression will be felt with raised and everted edges. An attempt should be made to determine whether the neoplasm is mobile, tethered or fixed, and to estimate the distance of the lower margin from the top of the anal sphincter complex: these factors are important in assessing resectability and methods of reconstruction following excisional surgery . In females, a vaginal examination may be useful if involvement of the posterior vaginal wall is suspected. Digital rectal examination also a ff ords the opportunity to evaluate the anal sphincter complex, which is important in cases where resection and low anastomosis is being considered. Rigid sigmoidoscopy Rigid sigmoidoscopy can be performed in the outpatient clinic and is useful to identify the neoplasm and possibly obtain biopsies. However, it requires the rectum to be empty of faeces and may require a prior rectal enema, which may not be practical in the outpatient setting. As colonoscopy is almost always required to visualise the whole colorectum, it is often easier and safer to obtain biopsies at this time. Colonoscopy A colonoscopy is required in most patients to exclude a synchronous tumour, be it an adenoma or carcinoma. If a proximal adenoma is found, it can be conveniently snared and removed via the colonoscope. If a synchronous carcinoma is present, the operative strategy is likely to change. If a full colonoscopy is not possible, for example when there is a be performed.