In general Rectal cancer has similar causes to colonic cancer. Its presentation may differ in that the patient may cause of tenesmus which is the senstation that they have not emptied the rectum post defectaion. The tumor may be palpable on rectal examination. In the male patient the clinician must be careful not to confuse the prostate gland with a mass in the rectum. In the female the clinican may be confused by the cervix, a ring pessary, a retroverted uterus or an ovarian mass. In both sexes the clinician may be confused by metastatic deposits in the pelvis.
The pecularities of rectal cancer are that preoperative staging of the local extent of the disease has important implications in management. This is much more so than it is in colonic cancer. There is no doubt now that advanced tumors of the rectum (T3, T4) are best treated by pre-operative neo-adjuvant chemo-radiotherapy. Outcome in rectal cancer, particularly with respect to local recurrance depends on the type of surgery done. Total excision of the mesorectum appears to be the best operation, which is associated with the best long term results. In addition the chance of preservation of the sphicters with ultra-low anterior resection and colo-anal anastamosis depend on the availability of a suitabily trained surgeon.