What is cancer?

Half of us will get cancer at some point in our lives – mostly in old age. But there are steps you can take to reduce your risk. Read on to find out more about what causes cancer, how it’s treated, and how to help prevent it.

Cancer can affect your body in different ways, such as:

• tumours can press on or block organs or affect how they function.
• cancer cells can spread (metastasise) to another part of your body.

What are the types of cancer?

Cancers are named after the types of cells they develop from. Below are the five main cancer types.

• Carcinomas. These are cancers that start in epithelial tissues, which include the skin and the tissues that cover internal organs. The most common type of cancer in the UK is carcinoma: they make up 85 out of every 100 cancers.
• Sarcomas. These are cancers of connective tissues, like bone and cartilage. They are relatively rare, with fewer than 1 in every 100 cancers being sarcomas.
• Leukaemia. This cancer affects the blood cells in the bone marrow, usually white blood cells. Leukaemias are the most common cancers in children.
• Lymphoma and myeloma. These cancers affect the white blood cells and blood plasma cells respectively, which are part of the immune system.
• Central nervous system cancers. These include cancers of the brain and spinal cord.

Common carcinomas include cancers of the breast, lung, prostate, and bowel. Together, these four cancers alone make up over half of all new cancers diagnosed in the UK.

What are the symptoms of cancer?

Cancer symptoms vary depending on the type of cancer, but there are certain symptoms to look out for such as:

• a new lump in any area of your body, for example in your breasts or testicles
• unusual bleeding, such as in pee, vomit, sputum or poo (stool), and vaginal bleeding between periods or after sex
• unexplained weight loss
• fatigue
• heavy night sweats or fevers
• a change in bowel habits

Symptoms like these can also be caused by other medical conditions. But diagnosing cancer early can make a big difference to how well it can be treated. So, if you ever notice any symptoms like these, or an unusual change that doesn’t go away, speak to your GP.

How is cancer diagnosed?

Cancer can be diagnosed based on your symptoms, from a biopsy, or from cancer screening.

If you have symptoms that could be caused by cancer, speak to your GP about them. Your GP may ask about your family history of cancer. You might also need tests, such as blood tests or an ultrasound scan, to figure out what’s causing your symptoms.

Your GP can refer you to a specialist if they think your symptoms may be caused by cancer. They may do a biopsy (a procedure that removes a small sample of tissue) to check if an unusual lump is cancerous (malignant) or not.

What cancer screening is available to me?

Cancer screening is normally offered to adults once they reach a certain age, depending on which part of the country they live in.

In the UK, cancer screening programmes include:

• breast cancer screening
• bowel cancer screening
• cervical screening
• lung cancer screening (in some areas of the UK)

How is cancer treated?

Treatments for cancer include:

• surgery – for example, to remove a tumour
• chemotherapy – this uses medicines to kill cancer cells
• radiotherapy – this involves high doses of radiation to kill cancer cells
• immunotherapy – using the immune system to fight cancer photodynamic therapy – using drugs activated by light to kill cancer cells
• targeted therapies – using drugs that specifically target cancer cells to stop them growing and surviving

Lots of cancers can be successfully treated, but there is a chance that some cancer cells can remain in the body and may come back years later. So, doctors sometimes say that cancer is in remission instead of using the word “cured”. This means that there are no obvious signs of cancer at that time.

Everyone is different, and several things affect whether a treatment is successful or not. For example:

• the type of cancer
• where it is
• how far it has grown or spread

Your gut microbiome - the types of healthy and unhealthy bugs in your gut, may also impact how well you respond to cancer treatment, but more evidence is needed.

What causes cancer?

Cancer isn’t contagious, which means you can’t catch it from other people. But there are several factors that increase your risk of getting cancer, such as your lifestyle and environment.

Age is the biggest single risk factor – more than a third of newly diagnosed cancers are in people aged 75 or older. You might also inherit genes that increase your risk of certain cancers, including breast, bowel, and ovarian cancers.

Lifestyle factors linked to cancer include the following.

• Tobacco. Smoking is the main cause of lung cancer, but it also increases risk of other cancers, including cancers of the bladder, bowel, pancreas, stomach, and oesophagus.
• Your weight. Being overweight or obese is the second main cause of cancer in the UK, second only to smoking. It increases the risk of several cancers, including breast, bowel, kidney, and oesophageal cancer.
• Alcohol. Drinking alcohol increases your risk of mouth and throat cancer, as well as cancers of the oesophagus, bowel, liver, and breast. And, the more alcohol you drink, the higher your risk of cancer, as well as other health problems.
• Diet. Processed meat – such as bacon, sausages, or preserved meat such as salami - can cause bowel cancer. A diet high in red meat, such as beef, pork, and lamb, could increase your risk of cancer too.
• Infections. Some infections increase your cancer risk. For example, a virus called human papilloma virus (HPV) can cause cervical cancer, and it’s also been linked with mouth and genital cancers.
• Lack of physical activity. Regular exercise can reduce your cancer risk in several ways. Physical activity boosts your immune system, lowers stress, and helps you keep a healthy weight. People who are physically active have a lower risk of breast and bowel cancer.
• Sun exposure and sunbeds. Ultraviolet (UV) rays can burn your skin, which increases the risk of skin cancer, including melanoma.

How can cancer be prevented?

Although not all cancers are preventable, around four in 10 cancers could be prevented by making lifestyle changes. This is because they’re caused by risk factors above, so taking steps to reduce these is very important. The following changes may help to reduce your risk of cancer.

• Stopping smoking, this is the leading preventable cause of cancer, both in the UK and globally.
• Eating a well-balanced diet, including fruits, vegetables, wholegrains, legumes, herbs, spices, nuts, and seeds will provide fibre for your gut bugs. These beneficial bacteria can help protect you against cancers, particularly bowel cancer.
• Maintaining a healthy weight. This reduces your risk of multiple cancers.
• Regular exercise. This can reduce your cancer risk in several ways. Physical activity boosts your immune system, lowers stress, and helps you keep a healthy weight. People who are physically active have a lower risk of breast and bowel cancer.
• Using sunscreen and covering up can help keep you safe in the sun, protect your skin from sunburn, and reduce your risk of skin cancer.
• Limit your alcohol intake. The less alcohol you consume, the lower your risk of cancer.

By making lifestyle changes, you can help lower your risk of cancer. If you’d like to know more about your cancer risk, why not try our cancer risk quiz?