Bowel cancer (s1) Flashcards
what is the bowel and what are the components of the bowel.
- part of the digestive system
- small bowel = small intestine (absorbs nutrients)
- colon = large intestine (absorbes water)
- rectum (stores faeces
what is bowel cancer and how does it form?
most common cancer found in the large intestine and rectum.
most bowel cancers start as non cancerous fleshy growths called polyps and are found on the walls of the intestine.
polyps do not cause symptoms but can become cancerous later on .
what age is bowel cancer most common in ?
over 60’s
what are the stages of bowel cancer
Stage 1: the cancer has grown through the inner lining of the bowel or onto the muscle wall. There is no cancer in the lymph nodes.
Stage 2: the cancer is localised. There is still no cancer in the lymph nodes.
2A- the cancer has grown into the outer covering of the wall
2B- the cancer has grown through the outer covering of the bowel and into the tissues and organs next to it. However, the cancer has not spread to other areas in the body.
Stage 3: this stage is divided into 3 parts
3A- the cancer is still in the inner layer of the bowel wall or has grown into the muscle. 1-3 lymph nodes may contain cancer.
3B- the cancer has grown into the outer lining of the bowel wall or onto surrounding tissues or organs. Between 1- 3 lymph nodes contain cancer.
3C- the cancer is any size. It has spread to more than 4 lymph nodes. The cancer has not spread to any part of the body.
Stage 4: the cancer has spread to other parts of the body, such as the liver, lungs or bones. The cancer is spreading through the lymphatic system and/or the bloodstream.
what are factors effecting the survival rate
- size of cancer
-type and grade of cancer - CEA levels
cancers causing holes on the bowel walls.
what is CEA and how does it relate to bowel cancer
CEA is a protein called carcinoembryonic antigen which some cancers make. if patients have a high level of this they have a worse survival rate.
signs and symptoms of bowel cancer
- Bleeding or blood in faeces with no obvious reason
- Changes in bowel habits (e.g. going more often, constipation ect)
- Losing weight for no reason
- Extreme tiredness, with no explanation
- Pain or lump in stomach.
what are fixed risk factors associated with bowel cancer
Risks you cannot change:
- Age (90 % of cases occur with people over 60)
- Family history (1st degree relative (mum, dad, sibling) diagnosed with cancer before 45)(2nd degree relatives, diagnosed at any age)
- Certain medical conditions
o Server ulcerative colitis or Crohns disease
o Diabetes
o Organ transplant history
o Gall bladder removal
o Previous history with bowel cancer
o Womb, testicular or lymphoma cancer
what are the main things patients can do to reduce their risk.
- maintain a healthy BMI
- quit smoking
- drink in moderation
- maintain a healthy diet
- maintain a healthy lifestyle
- take part in bowel screenings when it becomes available to you
how does maintaining a healthy diet reduce the risk of bowel cancer
- Excess fat changes the levels of sex hormones, like oestrogen or testosterone. This may increase the risk of cancer.
- The hormone insulin levels. When people are overweight or obese they tend to have higher levels of insulin. High levels of insulin can affect the levels of growth factors available to cells which tell them to divide.
how does smoking increase the risk of bowel cancer
- Smoking causes cancer as it can damage your DNA, as poisons can more easily stick to the DNA and increases the chances of causing more damage.
- Chemicals such as nickel and arsenic interfere with pathways for repairing damaged cells that will eventually turn cancerous.
- Smokers are also less able to handle harsh chemicals than those with healthy lungs and blood. immune system becomes less effective as it is harder to remove or neutralise toxins from the body.
- It can take many years for smoking to cause enough DNA damage to cause cancer. Research shows that for every 25 cigarettes smokes there is a DNA change that can cause a cell to become cancerous.
how does maintaining a healthy diet reduce the risk of bowel cancer
- eating lots of red meat and processed meat can increase the risk of bowel cancer. ( and possibly stomach and pancreatic cancer)
-red meat contains a naturally occurring pigment called haem, which can irritate and damage cells in the body. Haem can also fuel the production of harmful chemicals made by bacteria, which can lead to a higher risk of cancer. - almost all red meats contain a greater amount of haem than white meats.
-nitrates and nitrites are used to preserve processed meats. These nitrates and nitrites can be converted into cancer causing chemicals called N-nitroso compounds (NOCs). - cooking meats at high temps can produce cancer causing chemicals called heterocyclic amines and polycyclic amines (HCA and PCA)
- foods high in fibre reduce the risk of bowel cancer e.g. fruit, veg, wholegrains ect.
Fibres increase the size of faeces, diluted their contents and helps open the bowels more frequently. This reduced the amount of time harmful chemicals in the faeces stay in contact with the bowel. Fibre also helps gut bacteria produce helpful chemicals that change the conditions of the bowel.
how does drinking affect the risk of developing bowel cancer
- in the body ethanol is converted to a toxin called acetaldehyde.
- This can cause cancer by damaging DNA and stopping our cells repairing from damage.
- Acetaldehyde can cause liver cells to grow faster than normal, and these regenerating cells are more likely to pick up genes that can cause cancer.
- alcohol can cause highly reactive molecules called reactive oxygen species (ROS) to be produced in cells and can damage the DNA. Resulting in cancer to develop.
how does a healthy lifestyle reduce the risk of bowel cancer
- Maintaining a healthy lifestyle.
- Physical activity helps the food move through our bowels. This reduced the time at which the lining of the bowels may come into contact with harmful chemicals.
- Being active helps control levels of inflammation in the bowel.
- Inflammation is a natural reaction to an injury or infection but regular inflammation can lead to cells multiplying more frequently than usual and increases the chances of cancer.
what are the two types of screening available for patients, and why are they beneficial ?
- All men and women aged 60-74 . they are invited to carry out a faecal occult blood test (FOB). Every two years they are sent a test kit which allows them to collect a stool sample.
- Of you are over 75, you can ask for the test by calling the freephone helpline.
- An additional one of screening called a bowel scope screening is gradually being introduced for people over 55, where a doctor or a nurse look in the lower part of the bowel with a thin flexible instrument.
- Taking part in a bowel screening reduces the chances of dying from bowel cancer.
- Removing polyps found in screenings can prevent cancer.
