Bowel (Colorectal) Cancer Diagnosis and Treatment

Transcription

1 Bowel (Colorectal) Cancer Diagnosis and Treatment

2 Introduction The information in this document has been reproduced with the permission of the Colorectal and Stoma Care Team, Barts & the London NHS Trust. It intends to deliver comprehensive information on the diagnosis and treatment options for bowel cancer. It is not intended to assist in any way in self diagnosis. Should the reader be in any way concerned with their personal health we advise that you should visit your local GP for advice. What Area of the Body is Affected by Bowel Cancer? LIVER ASCENDING COLON TRANSVERSE COLON CECUM DESCENDING COLON RECTUM SIGMOID COLON ANUS The large bowel (colon and rectum) The bowel is part of the digestive system and is made up of 2 parts, the small bowel (small intestine or ileum) and the large bowel (large intestine). The large bowel consists of the large bowel (colon) and the rectum and together they form a long, muscular tube approximately 1.5m in length. Once food has been swallowed, it passes down the oesophagus (gullet) into the stomach and digestion begins. The food then passes into the small bowel where digestion continues and the body absorbs the nutrients. The digested food continues to the large bowel where water is absorbed and the waste matter or stool gradually forms. The stool is stored in the rectum / back passage, until it is ready to be passed out of the body as a bowel motion. 1

3 What is Cancer? The body is made up of cells, which grouped together form the tissues and organs of the body, for instance the brain, lungs and bowel. Cancer is a disease of the cells. Cells normally reproduce by dividing in a regular orderly way so growth and repair of the body tissues can occur. However, sometimes this process gets out of control and results in a lump developing within that group of cells. This is called a tumour. Tumours can be benign (noncancerous) or malignant (cancerous). A malignant tumour (cancer) has the ability to spread. Sometimes cells break away from the original (primary) cancer and spread to other organs in the body through the blood stream or lymphatic system. The lymphatic system is part of the body s defence against infection and disease. The system is made up of a network of lymph glands/nodes that are linked by fine ducts containing lymph fluid. When the cancer cells reach a new site, they may go on dividing and form a new tumour, often referred to as a secondary or a metastasis. What is Bowel Cancer? Cancer of the large bowel, also known as colorectal cancer, is the third most common cancer in the UK. Bowel cancer can affect the large bowel (colon) or the rectum (back passage). There are around 40,000 cases diagnosed every year in the UK and it is one of the most curable forms of cancer if found and treated in the early stages: When the disease is caught early and surgery can be effective, the cure rate can be around 90%. Even if the disease cannot be totally cured, patients can still have a good quality of life, and other treatments are often available. Cancer can be used to describe many different diseases. For most people the cause of their cancer is unknown, however most colorectal cancers develop from polyps. These form in the lining of the bowel and if left untreated can develop into cancer over a long period of time (sometimes several years). What causes polyps to form is unclear. By the time bowel cancer is diagnosed most are situated within the bowel wall and there is no evidence of the original polyp. An operation is needed to remove these cancers. NORMAL BOWEL SMALL POLYP CANCER DEVELOPS LARGE POLYP CANCER DEVELOPS 2

4 What Might Cause Bowel Cancer? The cause of bowel cancer is not fully known. However it is more common in Western societies and there is some evidence that it is linked to a Western diet. This diet is high in animal protein and fat and low in fibre (particularly wholegrains), a factor thought to increase the risk of developing cancer. Another risk factor is age. More than 8 out of 10 bowel cancers are diagnosed in people who are over 60 so the risk of developing bowel cancer increases as we age. Having a strong family history of bowel cancer may also increase the risk of developing the disease. However this is when bowel cancer has been diagnosed in a close family member (e.g. parent, sister or brother) under the age of 45 years. As with other cancers there have been links made between bowel cancer and smoking and too much alcohol is an additional risk factor. There is also increasing evidence that the amount of red or processed meat in the diet increases the risk. What are the Symptoms of Bowel Cancer? The symptoms of colorectal cancer are often very minor or not apparent at all. They may include: Change in bowel habit either diarrhoea or constipation Blood and / or mucus in your stool Stools that are smaller and /or narrower than usual Pain in the stomach or back passage cramps or tenderness Bloated sensation Frequency and sometimes painful wind Feeling as if the bowel does not empty properly Unexplained anaemia Unexplained weight loss Because bowel cancer can bleed on and off, it can commonly cause anaemia. This is a shortage of red blood cells in the body, leading to tiredness and sometimes breathlessness. Sometimes cancer of the bowel can cause a blockage. This is sometimes referred to as a bowel obstruction. The symptoms of this are: Griping pains in the abdomen Feeling bloated Constipation Being sick Other diseases, apart from bowel cancer, can cause these symptoms and sometimes people with bowel cancer do not have any of these symptoms. What is important is that anyone worried about possible symptoms should go to their GP WITOUT DELAY. Timely diagnosis saves lives. 3

5 How is Bowel Cancer Diagnosed? Investigations In diagnosing bowel cancer a number of different examinations and tests may be carried out. This will start with a visit to the GP who can then make a referral to hospital if necessary. Rectal examination - PR A doctor/nurse puts a gloved finger into the rectum and feels for any lumps or swellings. The examination may be slightly uncomfortable, but should not be painful. Sigmoidoscopy and Proctoscopy A doctor/nurse uses these tests to look inside the anus (proctoscopy) or rectum and lower part of the large bowel (sigmoidoscopy). While the patient lies on their side, the doctor/nurse puts a thin tube into the back passage and inflates the bowel with some air. Blowing air into the bowel helps the doctor to see inside more clearly. The tube also has a small light inside it, which again helps the doctor to see into the bowel. The doctor may take a biopsy (small sample of tissue) if necessary. This will be looked at under a microscope by a specialist to see if it contains any cancer cells. These tests can be done as an outpatient and individuals can go home after the test is over. The tests, although uncomfortable, are not normally painful and do not require an anaesthetic. A small amount of blood may be noticeable in the stools following the procedure but this is quite normal and should stop after a few days. Blood Tests In outpatients a variety of blood tests may be given. Some will be used to exclude other diseases, such as an under active thyroid or any Inflammatory Bowel Disease. The person requesting these will explain what the particular tests are for. Colonoscopy A colonoscopy is a test that allows the doctor to look directly at the lining of the large bowel (colon). In order to do the test, a colonoscope is carefully passed through the anus into the large bowel. The doctor is able to look down the colonoscope and get a clear view of the lining of the bowel. The doctor may take a biopsy a sample of the lining, for examination in the laboratory. A small piece of tissue is removed painlessly through the colonoscope, using tiny forceps. For this test the bowel has to be empty so the doctor can get a clear view. The patient will be given a list of things to do to help prepare the bowel for the test. The hospital will give detailed instructions about cleaning the colon. It is important to follow these. A sedative and painkiller is given just before the test to help relaxation; this is given via a small 4

6 needle placed into a vein, usually in the back of the hand or lower arm. The patient lies on their side and the doctor passes a flexible tube into the anus and up into the bowel and air is passed through it to distend the colon to give a clearer view of the lining. As the tube bends easily, it can pass around the curves in the bowel so the doctor can examine the whole length of it. The light side the tube helps the doctor to see any problem areas or swelling. A colonoscopy can be uncomfortable but the sedative and painkiller should help. The patient should be able to go home a couple of hours after the test. Because a sedative has been administered it is usually advised to have someone to go home with and patients are advised not to drive for 4 6 hours afterwards. Food and drink can be taken as normal immediately after the test. As this procedure does carry a very small risk of complication, the patient is asked to sign a form indicating that they understand why the procedure is being performed and what the risks are. Examination under anaesthetic (EUA) If a rectal cancer is suspected the medical team may decide to look at the area more closely whilst the patient is asleep. This test is usually carried out as a day procedure and requires a full anaesthetic. Prior to the test the patient is given an enema to clear out the rectum. CT Scan CT or CAT scan is the term used to describe a radiological test known as computerized tomography. The CT scanner is a doughnut-shaped machine that takes pictures of crosssections of your body, called slices. The CT can see inside the abdomen and other parts of the body, into areas that cannot be seen on regular x-ray examinations. CT makes it possible to diagnose certain diseases more accurately than with other imaging tools, as it shows images of the soft tissues. Anyone undergoing this test is asked not to eat or drink anything for 4 hours before the scan. Drinking water one hour before the test takes place enables a better outline of the organs during the scan. The test is carried out by a radiographer in a CT scan room where the patient lies down on the couch, normally on the back. Sometimes an injection of a contrast agent, a colourless liquid, is 5

7 given in the arm to clearly see organs and vessels. The radiographer cannot stay in the room but communication is possible via an intercom. The scan takes about 5 to 10 minutes. CT Pneumocolon This is a specialised scan which examines the large bowel. Patients will need to follow a special diet for 2 days prior to the test. Some laxatives will also need to be taken. MRI Scan A MRI scan is the term used to describe a radiological test known as Magnetic Resonance Imaging. MRI scanning combines a powerful magnet with a sophisticated computer to produce a picture of the internal organs without the need for x-rays, therefore making it low risk. Extensive evaluation has shown no known side effects as there is no use of radiation. There is no special preparation required before this test. Because there is a strong magnetic field, this could cause problems for patients with metallic implants. People with a cardiac pacemaker, cochlear implant, aneuryism clip in the brain, neuro stimulators and metallic objects in the eye are unable to undergo this scan. The magnetic field can also damage certain items; such as watches, hearing aids, electronic pagers or credit cards. Pregnant women are often excluded from this test. For this scan the patient is asked if possible to wear clothing with no metal parts such as zips or hooks, otherwise a hospital gown will need to be worn. Dentures, jewellery, hearing aids, hairpins and make-up also need to be removed. The patient lies on a couch which is 6

8 moved into the magnet. The scanner is quite noisy so headphones are worn during the procedure. The procedure lasts for 30 to 60 minutes and the radiographer is able to see and hear the patient at all times. Both the CT and MRI scan are usually used when a diagnosis of bowel cancer has been made or if this is suspected. They help to give the medical team more information about the cancer and to find out whether it has spread to other organs such as the liver or lungs. This information will then be used to assist the medical team in making decisions about treatment. Ultrasound scan An ultrasound scan is performed in the x-ray department and is an outpatient procedure. The test takes about minutes and patients go straight home afterwards. The scan involves passing a beam of sound via a small hand held device, like a microphone, over the abdomen. A clear jelly is used to lubricate the abdomen and provide good images: this may feel a little cold. This scan is performed regularly on pregnant women to gain a picture of the developing baby. This is a quick and risk-free way of looking at the internal organs, such as the liver and kidneys. Tissues of varying thickness reflect sound waves differently and these can be converted into a map by a computer. This map is shown on the computer screen on which the internal organs and any abnormalities within them can often be seen. The procedure is completely painless and the only preparation usually required is to have a full bladder. PET Scan PET stands for Positron Emission Tomography. This is a fairly new type of scan developed in the 1970s. It can show how body tissues are working, as well as what they look like. PET scans are used if there is uncertainty surrounding a diagnosis, for example if a CT scan is showing a lump in the liver but cannot confirm if it is cancer. With a PET scan the patient is injected with a very 7

9 small amount of a radioactive drug (tracer). The amount of radiation is very small no more than you have during a normal x-ray and it only stays in the body for a few hours. Depending on the drug, it will travel to particular parts of the body. The most common drug is fluorine 18 also known as FDG-18. This is a radioactive version of glucose. When FDG-18 is injected into the body it travels to places where glucose is used for energy. It shows up cancers because they use glucose in a different way from normal tissue. After the injection the patient rests for about an hour to allow the radioactive tracer to spread through the body. The scan itself can take up to an hour and produces an image of the radioactive tracer in the body. It is important to lie as still as possible while the scan is being done. The scan should not be painful or uncomfortable but a buzzer is available for use if the patient is feeling unwell. There are no side effects of this type of scan and after the scan normal diet and activities can be resumed. How is Bowel Cancer Treated? Treatment for bowel cancer can vary depending on the location of the tumour. In the large bowel (colon) the main form of treatment is surgery to remove the cancer. Once removed it is analysed at the laboratory and the specimen is staged (see below). Depending on the results of these tests the doctor, together with the multidisciplinary team, may decide that further treatment is needed in the form of chemotherapy. If rectal cancer is diagnosed a combination of radiotherapy (x-ray treatment) and chemotherapy may be used to shrink the tumour, before surgery being carried out to remove the cancer. Once surgery has been completed, further treatment may be required in the form of chemotherapy. In some instances (e.g. if the cancer has spread to other parts of the body) surgery is not the best option, and other treatments such as radiotherapy or chemotherapy are used instead. Radiotherapy Radiotherapy is the use of x-rays or other high-energy rays to kill cancer cells and shrink tumours. The treatment is individually planned and monitored for each patient and is given as a series of short, daily treatments in a radiotherapy department using equipment similar to a large x-ray machine. Each treatment is called a fraction. Giving the treatment in fractions ensures that less damage is done to normal cells than to cancer cells. The damage to normal cells is mainly temporary, but is the reason why radiotherapy has some side effects. For most curative (radical) treatments, planning is a very important part of radiotherapy and may take a few visits. Careful planning makes sure that the radiotherapy is as effective as possible. It ensures the radiotherapy rays are aimed precisely at the cancer and cause the least possible damage to the surrounding healthy tissues. The treatment is planned by a cancer specialist (clinical oncologist) and a physicist. A first treatment may happen on the same day as a planning session but often it is necessary to wait a few days while the physicist and specialist prepare the final details of the treatment. 8

10 Chemotherapy Chemotherapy is a drug treatment. It is the use of cytotoxic (toxic to cells) drugs that destroys cancer cells by interfering with their ability to divide and grow. It can be used in combination with radiotherapy prior to surgery for rectal cancer or after surgery for colon cancer (depending on the stage of the cancer). The drugs can be given by mouth, an injection into the vein or through a central venous catheter. Combination treatment A combination treatment of chemotherapy and radiotherapy is often used to treat rectal cancer to shrink the tumour before it is removed during surgery. Exact treatment plans depend on what the doctor considers is best for the individual patient. All aspects of adjuvant (treatments in addition to the primary treatment) therapy are discussed in detail with the patient. Colorectal surgery The main treatment of colorectal cancer is surgery. The aim of surgery is to remove the affected tissue. The surgeon will also remove lymph nodes near the intestine and everything will be looked at under the microscope to determine whether there is a cancer and if it has spread outside the colon or rectum. All patients undergoing major surgery are put on the enhanced recovery programme. This involves allowing the patient to eat and drink earlier following surgery and also allows all of the tubes to be removed quickly allowing faster mobilisation and return to normal activities. Patients are looked after by a dedicated team with a special enhanced recovery nurse to coordinate care and safe discharge from hospital. Laparoscopic keyhole Surgery Laparoscopic surgery is now sometimes offered to patients depending on the hospital. The operations are performed through tiny incisions that are less painful and allow a quicker recovery from the operations. Although nearly all patients are offered this type of surgery some patients may not be suitable for a number of reasons. Removal of bowel is called a resection and will have one of two outcomes: I. The bowel is reconnected by a join called an anastomosis which re-establishes the continuity of the bowel. II. If the surgeon is not able to sew the colon back together, they will make an opening (stoma) on the outside of the body for waste to pass out of the body. This results in the formation of a colostomy or ileostomy. Sometimes, the stoma is only needed until the colon has healed, and then it can be reversed. However, if the entire lower colon has to be removed 9

11 the stoma will be permanent. Stoma patients receive a great deal of support both at hospital and at home. The outcome of the operation will depend upon the size of the tumour. The surgeon and specialist nurse discuss this with the patient and provide written details of the proposed operation. However, on the day circumstances which come to light when in theatre may mean that another course of action has to be taken. Staging of Cancer The staging of a cancer tells the doctor how far the cancer has spread (metastasised). It is important because chemotherapy treatment after surgery is often based on the stage of a cancer. It may not be possible to stage the cancer properly until after surgery. However, the scans and tests that are carried out may give an idea of the stage and sometimes a decision can be made about giving other treatment (e.g chemoradiotherapy) before surgery. TNM Staging TNM represents Tumour, Nodes and Metastases. The system assesses the extent of the tumour s local spread (invasion), the regional lymph node involvement and the presence of metastases in distant organs. The T number is governed by tumour size and the extent of its invasion of the various layers of the bowel wall. The N number is decided by the number and range of lymph nodes enlarged, and their tissue replaced by tumour cells. The M refers to the extent of metastases; secondary appearance in other organs, most often the liver. Are there any alternatives to surgery? Non-surgical options do not cure and surgery to this day offers the best chance of the cancer being removed and a full cure. This is why it is so important to deal with any symptoms as soon as they are experienced. 10