Colon and Rectal Cancers
Once a diagnosis of either a colon cancer or rectal cancer has been made, it is important to that your patient sees a Specialist General or Colorectal Surgeon and that the details of their case are discussed at a Combined Multi-disciplinary Management Meeting (MDM). Each case is different and requires the input of all specialists, as well as allied health professionals to ensure the best possible decisions and ongoing care.
For tumours of the large bowel (colon), chemotherapy is often recommended after surgery in order to reduce the risk of spread of microscopic disease and improve overall survival. This is especially the case in most T3 and nearly all T4 tumours, node positive disease, or if a patient initially presents with high risk features such as obstruction or perforation of the bowel.
These pathological factors are considered along with the age, prognosis, performance status and, importantly, the patient's own preference when considering further treatment recommendations. The MDM is an essential tool in recording this information and formulating treatment plans.
Post-operative, curative intent radiotherapy for colon cancers is only usually offered in the case of macroscopically positive resection margins or unresectable disease. It is usually combined with concomitant chemotherapy in these instances.
For tumours of the rectum, six weeks of pre-operative, combined chemotherapy and radiotherapy are standard now in order to reduce the risk of recurrence of the primary rectal cancer as well as shrink or "down-stage" the tumour, which can permits an easier operation and avoid a permanent colostomy bag.
Surgery is performed six weeks after completing combined chemo-radiation, which is enought time for the body time to recover. Sometimes, further chemotherapy or other systemic therapy is recommended also, depending upon what the specialist pathologist sees in the tumour under the microscope after surgery. Quite often, no viable tumour is visible in the resected rectum, indicating a complete response to the chemoradiation.
The side effects of radiotherapy for colon and rectal cancers are unique to each case, as it depends upon the extent of surgery and whether it is delivered pre-operatively or post-operatively.
Pre-operative, concomitant chemoradiation, known as neo-adjuvant therapy, is more common for locally advanced rectal cancers and is usually very well tolerated over the five week course.
Common, early side effects from the radiotherapy component include fatigue, a skin reaction, mild proctitis and mild cystitis. A total mesorectal excision is then performed and most of the irradiated tissue is removed, making late side effects rare.