In a number of my previous posts I discussed the various types of cancer. However, one thing I failed to do in these posts was to actually define cancer and explain what it is. That’s why today I am going to discuss exactly what cancer is and explain the various types, causes, signs & symptoms, tests and the treatments available.
WHAT IS CANCER?
Cancer is a disease that affects the body’s cells. Every cell contains deoxyribonucleic acid (DNA), a substance that contains coded instructions called genes. These genes tell the body’s cells when to divide and reproduce and when to die. This leads to a controlled process where old cells die and existing cells divide to create new cells that replace them. However, when DNA becomes disrupted or damaged in a cell it may start to divide uncontrollably or not die when it should. Every time that cell divides the disrupted or damaged DNA is reproduced leading to an increased number of cells that are dividing uncontrollably and not dying when they should. These rapidly multiplying cells eventually cause a lump to develop which is referred to as a tumour.
Tumours can be either benign (non-cancerous) or malignant (cancerous). Benign tumour cells do not spread to and affect other areas of the body. However, they can still cause problems if they grow continuously and start to press against surrounding organs. Malignant tumour cells can spread to and affect other areas of the body making them much more dangerous. If a benign tumour is identified and removed it will not cause any further problems. If a malignant tumour is identified and removed it can still cause problems if the cancerous cells spread to other areas of the body and further malignant tumours develop.
WHAT TYPES OF CANCER ARE THERE?
There are four main types of cancer:
1) CARCINOMAS:- Carcinomas are cancers that develop in the lining of the body (the skin) and the organs. They are the most common type of cancer representing around 85% of cancer cases. There are four main types of carcinoma;
– Squamous Cell Carcinoma (cancer that develops in the lining of the mouth, gullet and airways).
– Adenocarcinoma (cancer that develops in the lining of glands in the body).
– Transitional Cell Carcinoma (cancer that develops in the lining of the bladder and the urinary system).
– Basal Cell Carcinoma (cancer that develops in the skin).
2) LEUKAEMIAS & LYMPHOMAS:- Leukaemias and lymphomas are cancers that develop in the tissues where white blood cells are created. They represent around 7% of cancer cases.
3) SARCOMAS:- Sarcomas are very rare cancers that develop in the connective tissues of the body. They represent less than 1% of all cancer cases but can be split into two types:
– Bone Sarcomas (cancer that develops in the bones).
– Soft Tissue Sarcomas (cancer that develops in other connective tissues e.g. muscle, fatty tissue).
4) OTHER CANCERS:- Brain tumours and other rare tumours make up the remaining types of cancer.
WHAT CAUSES CANCER?
As I already mentioned, anything that damages or disrupts the genes can eventually cause cancer. However, there are a number of further factors that can influence your chances of developing cancer and I have discussed these below:
1) AGE:- The normal process of cell division is not 100% perfect. Every time our cells reproduce tiny errors may occur. On top of this many of the chemical reactions that occur in our body’s cells release DNA damaging by products. As we get older our cells have replicated more times and more chemical reactions have occurred. Therefore, the chances of these tiny errors being replicated and our DNA becoming damaged is increased.
2) CARCINOGENS:- There are numerous substances that can damage our DNA. These include; asbestos, car exhaust fumes, tobacco smoke, radiation and ultraviolet light. The greater our exposure to these substances the greater the risk of our DNA becoming damaged.
3) POOR DIET:- Diet is believed to influence your overall cancer risk although it is not fully understood which elements of diet have an impact. Research has suggested that fresh fruit and vegetables can help prevent cancer (possibly because they contain antioxidants which help protect from and repair cellular damage) whilst fatty, processed foods can increase your risk of developing this disease.
4) LACK OF EXERCISE:- Regular physical activity is believed to protect you against multiple types of cancer whilst a lack of exercise can increase your chances of developing certain types. However, it is not known why exercise affects your likelihood of developing cancer in this way.
5) INHERITED GENETIC CONDITIONS:- There are a number of inherited genetic conditions that increase your chances of getting cancer. For example, women who are born with a mutated BRCA gene are more likely to develop breast cancer and ovarian cancer than women who do not have this mutation.
6) VIRUSES:- Certain viruses increase your cancer risk. For example, the human papilloma virus (HPV) can make you more likely to develop cervical cancer.
7) WEAK IMMUNE SYSTEM:- People who have a weak immune system are more likely to develop cancer. It is not fully understood why this is the case but it is thought to be because people with a weak immune system cannot combat viruses that are linked to cancer.
WHAT ARE THE SIGNS & SYMPTOMS OF CANCER?
Cancer is often difficult to detect and the symptoms are often related to specific types of cancer. For example, coughing often indicates lung cancer whilst problems urinating are more likely to suggest prostate cancer. However, there are a number of general symptoms that you can look out for and I have listed these below:
1) LUMPS:- Tumours can sometimes lead to the formation of lumps on the skin. If you notice any bumps or lumps that were not there before you should go see your doctor right away. Most lumps turn out to be non-cancerous but they should still be treated with suspicion. Your doctor will be able to perform a proper diagnosis and do further tests if necessary to determine whether any lumps are cancerous.
2) CHANGES IN BOWEL HABITS:- If you notice any unusual bowel habits this is a possible sign that a tumour has developed. Rectal bleeding, problems urinating, constipation and diarrhoea are all potential signs of cancer. If you notice any changes to your regular bowel habits you should inform your doctor immediately.
3) BLEEDING:- Unexplained bleeding is almost always a sign that something is wrong. Coughing up blood is a potential sign of lung cancer whilst rectal bleeding can indicate prostate cancer and ovarian cancer. If your skin starts to bleed this could be a sign of skin cancer whilst nosebleeds are a potential sign of leukaemia. Bleeding may not necessarily be linked to cancer but it could be linked to organ damage or another disease. Any unnatural bleeding should be treated with suspicion and you should see your doctor right away.
4) UNEXPLAINED WEIGHT LOSS:- Weight loss that cannot be explained is another sign that something is wrong. If a tumour has developed in the digestive tract it could cause blockages and stop you digesting food properly. Certain tumours also release chemicals that increase your metabolism meaning that you burn more calories than usual. If you notice you have lost weight and cannot think of any rational reason then go and see your doctor and explain your concerns.
WHAT ARE THE TESTS FOR CANCER?
There are a variety of cancer tests available. Some of these test are tailored to specific types of cancer. For example, a mammogram is used to test for breast cancer. However, other tests can be used to universally test for a wide range of cancers and I have outlined these below:
1) PHYSICAL EXAMINATION:- A physical examination is the first test used for a variety of cancers and will be performed by your doctor. For cancers where there are obvious physical symptoms your doctor will often inspect your body for these signs. For example a physical exam for prostate cancer will involve your doctor using a gloved finger to feel for any abnormalities in the prostate. Even cancers that do not have any immediately obvious physical symptoms may involve a physical examination. For example the first test for lung cancer will often involve your doctor assessing your overall health, measuring how much you smoke and listening to any coughs you might have.
2) X-RAY:- An x-ray allows your doctor to see any abnormalities or lumps that may turn out to be cancerous. These abnormalities may turn out to be non-cancerous but they can also be an early warning sign for cancer.
3) COMPUTERISED TOMOGRAPHY (CT) SCAN:- A CT scan uses multiple x-rays to build a 3D picture of the inside of your body. This will then provide your doctor with a more detailed 3D view of any potential abnormalities.
4) ULTRASOUND:- An ultrasound involves using sound waves to build up an internal picture of your body. For some types of cancer an ultrasound is more useful than an x-ray or CT scan because it reveals whether any lumps are fluid (and therefore non-cancerous) or solid (and potentially cancerous).
5) ENDOSCOPY:- This involves your doctor using a small, thin, flexible tube with a camera on the end to inspect the inside of your body and look at any abnormalities in more detail. There are many different types of endoscopy. For example, a bronchoscopy involves inserting a small, thin, flexible tube down your throat to look at the inside of your airways whilst other types involve making a small incision in a part of the body to insert the endoscope.
6) BIOPSY:- This involves your doctor using a special type of needle to take a tissue sample which can then be analysed under a microscope for the presence of cancerous cells. Certain types of endoscope can also be used to perform a biopsy. Although this is one of the best cancer tests available it is not 100% accurate with some biopsies coming back negative despite cancerous cells being present.
WHAT ARE THE TREATMENTS FOR CANCER?
Just like the tests for cancer there are also a variety of treatments for cancer available. However, the three main types are surgery, chemotherapy and radiotherapy.
1) SURGERY:- Surgery attempts to remove the cancerous tumour from the body. The effectiveness of surgery will generally depend upon how far the cancer has spread. With early stage cancers surgery is usually very effective and the whole tumour can be removed. However, with more advanced cancers surgery may not be possible.
2) RADIOTHERAPY:- Radiotherapy involves using high energy radiation rays to kill cancer cells. It can sometimes be used as an effective cancer treatment but it is mostly used either pre-surgery (to shrink the cancerous cells and make the surgery easier to perform) or post surgery (to kill off any remaining cancerous cells). Radiotherapy is also used to improve the quality of life in cancer patients when the cancer is no longer treatable. This type of cancer treatment can sometimes lead to nausea and vomiting depending upon the strength of the radiation used
3) CHEMOTHERAPY:- Chemotherapy uses anti-cancer medications to kill or shrink cancerous cells. Like radiotherapy it can treat some cancers effectively but it is generally used to make surgeries easier to perform and kill off any cancer cells after surgery. Chemotherapy treatment is not perfect because it often kills non-cancerous cells too. As a result chemotherapy patients often suffer from a number of unwanted side effects including hair loss, nausea and diarrhoea.
WHAT CAN BE DONE TO PREVENT CANCER?
There is no sure fire way to prevent cancer. Someone who is very healthy may develop this disease early in their life whilst another person who smokes and drinks heavily and leads a sedentary lifestyle may never suffer from this disease. However, there are are a number of lifestyle changes you can make that greatly reduce your chances of developing this disease.
1) QUIT SMOKING:- Cigarette smoke contains over 70 carcinogens (chemicals that damage the DNA and cause cancer to develop). Every time you smoke a cigarette these carcinogens are transported to your lungs greatly increasing your chances of developing lung cancer and small cell lung cancer. However, from the lungs these carcinogens can also pass to other areas of your body via the blood and the lymphatic system greatly increasing your risk for other types of cancer. Quitting smoking cuts out these carcinogens and is therefore one of the best ways to prevent cancer from developing.
2) EAT HEALTHY:- The links between diet and cancer are still not fully understood. However, eating a healthy diet does seem to help prevent a number of types of cancer. Diets that are rich in fruits and vegetables, high in fibre and full of vitamins are believed to help reduce your cancer risk possibly because vitamins contain antioxidants that help protect your cells and DNA from damage whilst fibre can help your body fully absorb these vitamins and minerals from the foods you eat.
3) EXERCISE REGULARLY:- Like with diet it is not known why regular physical activity can help prevent certain types of cancer. However, your risk of developing colon cancer, breast cancer, prostate cancer and ovarian cancer (to name a few) are all thought to be lowered if you participate in regular physical activity.
4) REDUCING YOUR ALCOHOL CONSUMPTION:- Alcohol consumption is another factor that has an influence on your chances of developing cancer. It is not known exactly why but this article suggests it could be down to acetaldehyde (the hangover chemical), the effect alcohol has on your hormones, the effect alcohol has on your folate levels and the damage alcohol causes to your body’s cells. The more alcohol you consume the greater your cancer risk is thought to be.
However, the way in which you consume this alcohol is not thought to affect your chances of developing cancer. For example, if you consume 10 units of alcohol per week you are more likely to develop cancer than someone who consumes 5 units per week but the way you drink these units has little to no impact. Whether you drink 2 units a day Monday to Friday or all 10 units on Friday night your cancer risk will be the same.
I hope this article has helped you understand what exactly cancer is and given you a brief overview of the topic. Although there is plenty more research to be done on cancer there are definite links between cancer and lifestyle. Although it is not the only factor, by leading a healthy, fit, active lifestyle and eating nutritious whole foods you can seriously reduce your risk of contracting cancer.
Whilst every intention has been made to make this article accurate and informative, it is intended for general information only. Cancer is a very serious, life threatening condition and you should discuss any concerns, treatments or lifestyle changes fully with your doctor.
Sources:
How does Alcohol cause Cancer? (Cancer Research UK)
What is Cancer? (BBC)
What is Cancer? (Cancer Backup)
What is Cancer? (Cancer Research UK)