This article discusses the symptoms, screening for and treatment of bowel cancer including the latest surgical techniques. This information will be of value to anyone who has been diagnosed with colorectal cancer or related metastases.
Treating Colorectal Cancer - Contents
- Early diagnosis of bowel cancer is critical
- Rectal bleeding and a change in bowel habit
- Diagnosing extent of disease (staging)
- Treatment of early stage colorectal cancer
- Surgical objectives
- Types of surgery for bowel cancer
- Treatment of advanced colorectal cancer
- Resectable liver metastases
- Resectable lung metastases
- Brain and bone metastases
Bowel cancer is a major health problem in the United Kingdom. Men and women are equally affected by the disease and improved survival is dependent on the diagnosis and surgical treatment of early stage disease (no cancerous spread to the lymph glands or distant organs). It is now widely accepted that most bowel cancers arise from pre-cancerous polyps, and that early detection of these polyps through screening offers the opportunity to prevent bowel cancer developing and to treat the condition before it progresses to an advanced stage. A smaller proportion of bowel cancers are inherited and a detailed family history by the specialist is required to identify those who may be at risk of the disease.
The presentation of bowel cancer may vary from no symptoms at all to worrisome complaints such as rectal bleeding, a change in bowel habit, weight loss and anaemia (low blood count). Sometimes an abdominal swelling arising from the colon may be felt by the patient or their doctor. Diagnosis is made by visualising the entire length of the large bowel with a fibre optic camera (colonoscope) to locate the site of the tumour, and then obtaining tissue samples for confirmatory diagnosis. Sometimes it is not possible to complete the colonoscopy for technical reasons or the patient may be considered unfit for the procedure. In such circumstances, a barium enema or CT-pneumocolon / virtual colonoscopy are acceptable alternative methods of examining the large bowel.
Once a diagnosis of bowel cancer is confirmed, your surgeon will arrange additional tests in the form of a body scan – either CT or MRI to establish whether the disease has spread to nearby lymph glands or perhaps to more distant organs like the liver or lungs. This process is known as staging the disease and is necessary before curative surgery is contemplated. Each newly diagnosed case is discussed at a colorectal cancer multidisciplinary meeting made up of cancer specialists who will be involved in the care of the patient care. At this meeting, it is established whether the patient has early or advanced disease and the best evidence based treatment plan is agreed and then recommended to the patient.
The single most effective method of treating early stage bowel cancer is radical surgical excision (removal) of the affected bowel. The term “early stage” disease implies that the cancerous growth is confined to the bowel wall and has not spread locally or to distant organs. Sometimes but not often, isolated spread of bowel cancer to the liver or lungs may also be treatable surgically by liver and chest specialists respectively, with good long term results.
The surgical options for treating early stage disease whether by the traditional “open” surgical technique or more recently, by laparoscopic or “keyhole” approach, aims to achieve the following;
- Removal of the segment of bowel containing the cancer with clear margins (no tumour cells identifiable at the cut ends of the bowel).
- Radical excision ensuring that sufficient lymph nodes are harvested (generally greater than 12). This is particularly important because the absence of cancerous cells in any of the lymph glands harvested, indicates early stage disease with very good prognosis and potentially curative.
‘Keyhole’ or laparoscopic surgery is a new effective alternative technique to traditional open surgery for the treatment of colorectal disorders including bowel cancer. This novel method of minimal access surgery has rapidly gained wide acceptance amongst bowel surgeons and nearly all colorectal conditions can be treated using this approach.
A telescopic camera and working instruments measuring between 5-10mm in width are introduced through skin incisions (port-sites) into the abdominal cavity distended with air or carbon dioxide. This enables the operation to be performed using working instruments. Tissue or parts of abdominal organs such bowel can be removed by lengthening the port-site incision to about 4cm, although this may vary depending on the patient’s overall size and body shape.
In comparison to open surgery, the key-hole approach results in less post-operative pain and earlier discharge from hospital. The reduced need for painkillers means that after the operation patients are able to move around much sooner and have a rapid return of normal bowel function. Another significant advantage of minimal access surgery is that scarring from small wounds give better cosmetic results (see Figures 1-2) and minimise problems that can arise from internal scar tissue formation (adhesions) after open abdominal operations.
There were initial concerns that the procedure took a long time (4-7 hours), failed to harvest sufficient number of lymph glands (good predictor of prognosis) from the bowel specimens, and that there was an increased risk of leaving some cancer cells along the path of the port sites (port-site cancer spread). However, clinical trials in the United States, UK and Europe comparing the keyhole technique with traditional open surgery for bowel cancer have refuted these concerns concluding that the two techniques are equivalent. Furthermore, the trials showed that the key-hole technique provided the additional benefits outlined above.
Most patients are suitable for laparoscopic surgery but the final decision rests with the operating surgeon. Some patients may not be suitable because of a variety of medical reasons including previous multiple open abdominal operations. This will be established during consultation with your specialist.
Where the disease has already spread to the lymph glands or surgical clearance is incomplete or threatened, additional treatment (adjuvant) with chemotherapy / radiotherapy or a combination of the two may be required.
In some cases when bowel cancer is locally advanced (has spread to nearby or surrounding tissue), chemotherapy with or without radiotherapy may be given before surgery (neo-adjuvant therapy) to reduce the size of the tumour and increase the chance of surgical clearance of the disease. Patients with widespread (disseminated) disease or irresectable bowel cancer unresponsive to chemotherapy or radiotherapy (see below), are referred to the palliative care team for supportive therapy and review.
Generally chemotherapy is advised when the disease has spread beyond the bowel wall. It is an attempt to treat the whole body with chemical agents that are toxic to cancerous cells wherever they might lodge. Unfortunately, these agents are also toxic to normal cells and explain some of the side effects of treatment suffered by some but not all patients. Standard systemic chemotherapy involves various combinations of a variety of drugs such as Oxaloplatin, Irinotecan, 5 FU and more recently monoclonal antibody agents. There is good evidence of survival benefit (patients live longer) with these chemotherapy agents when compared to those with advanced disease not receiving these drugs.
Radiotherapy may also be suitable following sub-optimal surgery particularly in a confined area like the human pelvic region. This form of treatment is designed to directly destroy any residual cancerous cells within the operative field. Radiotherapy may also be given combined with chemotherapy and the rationale here is that the chemotherapy agents sensitise the malignant cells to destruction by radiation. Radiotherapy treatment may be administered as long (6 weeks) or short (1 week) course treatment and is determined during the patient’s case review at the colorectal cancer multidisciplinary team meeting.
This term describes treatment with chemotherapy, radiotherapy or a combination of the two before surgical intervention is contemplated. There is now good evidence from clinical trials that combining the two treatments before surgery leads to shrinkage of the cancer and in some cases the cancer is known to have disappeared completely! Furthermore, reducing the size of the tumour using this approach permits surgical removal which otherwise may not have been possible because of the original size of the tumour or its location.
Cancer spread to the liver maybe resectable (removable) surgically with improved patient outcome provided it meets the following criteria:
- Tumour is confined to a section of the liver that can be safely removed.
- There is no sign of the cancer elsewhere.
- Major blood vessels and bile channels within the liver can be preserved with good function of the remaining liver tissue.
The above criteria are by no means exclusive because with recent advances in technology, liver surgeons can now combine surgery with newer treatments like radiofrequency ablation (RFA) in order to provide greater flexibility in patient selection. Using this approach 40% five year survival rates have been reported.
Tumour deposits involving one or both lungs can also be resected surgically with good survival rates of 30% at five years. Similar criteria are adopted as with resectable liver metastases with or without radio frequency ablation.
Spread of colorectal cancer cells to the brain or bone indicates that the disease is advanced and incurable. However, much can now be done for these patients to improve their quality of life. Spread of disease to the bone results in weakening of bony tissue which can easily break. By fixing the affected bone using specialist orthopaedic prosthesis will minimise pain or discomfort [see article on Image guided radiofrequency ablation (RFA) of bone metastases]. Similarly, symptoms arising from spread of tumour cells to the brain can be treated effectively with special drugs that reduce brain swelling. Unfortunately, some patients fail to respond to the above treatment and are referred to palliative care specialists whose primary function is to manage patient symptoms and ensure that they are comfortable and do not suffer any pain or discomfort.
Curing colorectal cancer is dependent upon early detection or prevention of the disease. Laparoscopic (keyhole) surgery is a new and effective alternative technique for the treatment of bowel cancer. Advancing technology has seen the emergence of newer strategies for managing advanced disease with improved patient outcome.