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Common questions about cancer

We answer common cancer questions: find out what cancer is, how it spreads and what we can all do to prevent it.

What is cancer?

Cancer is a disease where the normal regulation of cells in the body is broken and they grow abnormally. A healthy cell will replicate itself to replace old cells that die. But if a cell’s DNA is damaged, the cell won’t work properly.

The cell may replicate uncontrollably or not die when it should and become a tumour. These tumours can form in many different parts of the body, which is why there are so many different types of cancer.

How does cancer spread?

Cancers are usually named after the organ in which they start, for example bowel cancer. However, some cancers spread, either locally (into the tissues surrounding the cancer) or into other parts of the body – a process called metastasis.

This happens when cancer cells break away from the tumour and move through the bloodstream or lymphatic system. They can end up in another organ such as the liver or lungs, and begin replicating to form another tumour.

What is the most common cancer?

Over 393,000 new cases of cancer were diagnosed in the UK in 2021 – sadly that’s more than 1,000 people every day. The most common cancers in the UK are breast and prostate.

But around 157,000 cases could be prevented if everyone was healthier by not smoking and by maintaining a healthy weight, being active and eating a healthy diet.

Globally, lung cancer is the most common, closely followed by breast cancer.

Why is cancer on the rise?

The main reason that cancer rates are increasing is because people are living longer; the older you are, the more likely you are to develop cancer.

However, increasing rates of obesity and physical inactivity, the rise of smoking in low- and middle-income countries, and people eating unhealthy diets are also contributing to a rise in preventable cancers.

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Which foods cause cancer?

There is no single food or ingredient that will have a large impact on whether you do or don’t get cancer. Rather, the regular patterns of what we eat combine to make us more or less susceptible to cancer.

For example, eating lots of fruit, vegetables, beans, pulses and wholegrains lowers your risk of cancer, but eating too much red or processed meat increases your risk of bowel cancer.

Eating too much food that’s high in fat or sugar tends to lead to excessive calorie intake and weight gain, which itself is a cause of several types of cancer.

In addition, alcohol (from any type of alcoholic drink) increases the risk of several cancers.

Is cancer genetic?

Anyone can get cancer, but a small number – about 5–10% – are strongly inherited, meaning they are passed from parents to child.

One example is a certain type of breast cancer that occurs due to mutations, or errors, in two genes: BRCA1 (BReast CAncer gene one) and BRCA2 (BReast CAncer gene two).

However, inheriting a mutated gene does not mean you will definitely get that cancer; rather that you have a higher risk.

Following our Cancer Prevention Recommendations is therefore even more important.

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How is cancer treated?

Cancer can be treated in different ways including surgery, radiotherapy, chemotherapy, immunotherapy, targeted therapy and hormone therapy. Most people will have a combination of these, and people with the same cancer may receive different treatment based on:

  • where in the body the cancer originated (the primary cancer).
  • the size of the tumour and whether the cancer has spread (stage of cancer).
  • how fast the cancer is growing (the grade of cancer).
  • symptoms you may have from the cancer.
  • general health.

At World Cancer Research Fund we’re researching if and how exercise can be used after a diagnosis of cancer. Some evidence suggests that exercise before treatment (prehabilitation) can make you fitter and healthier, and therefore better able to cope with the side-effects of treatment. Exercise during treatment may speed up recovery.

What actually kills the cancer cells?

Cancer drugs, such as chemotherapy, kill cancer cells in different ways, such as by attacking the DNA, which stops the cell replicating and so it eventually dies.

But chemotherapy can make people feel very poorly because the drug cannot tell the difference between cancer cells and healthy cells.

This can lead to side-effects such as nausea and hair loss.

> If you or someone you love is going through cancer treatment we have practical tips to help you manage.

Is cancer curable?

Cancer is categorised into different stages depending on how large the tumour is and how far it has spread:

  • Stage I – when the cancer is small and only in one area.
  • Stage II – when the tumour is larger but has not spread.
  • Stage III – when the cancer has spread to nearby tissues or lymph nodes.
  • Stage IV – known as advanced stage or metastatic cancer, this is when the disease has spread to other parts of the body.

Usually, the earlier cancer is diagnosed, the better the chance of treatment being effective. However, stage IV cancer can still be treated to prolong survival and improve quality of life.

Each cancer is different, which is why we generally don’t talk about “curing cancer”. However, advances in treatment and technology mean we are closer than ever to being able to remove all traces of certain cancers from someone’s body. Known as complete remission, this could be considered a cure.

Which cancer type has the lowest survival rate?

Survival rates and prognosis depend on the cancer, the stage and the health of the person. However, pancreatic cancer has the lowest survival rate in the UK, mainly because it’s usually not discovered until it’s quite advanced.

It’s also important to remember that cancer frequency is not the same as cancer mortality. Skin cancer is the fifth most common cancer in the UK, but has the highest survival rate. However, any cancer diagnosis can be shocking.
> If you or someone you love has had a cancer diagnosis, explore our section on living with cancer and coping with side-effects.

Where does cancer research money go?

Donations to cancer charities go towards research, treatment, education and palliative (end of life) care. At World Cancer Research Fund, we focus on the effect of diet, nutrition and physical activity on the prevention of cancer, and its impact after a diagnosis of cancer.

We know that about 40% of all cases could be prevented if everyone was healthier by not smoking, maintaining a healthy weight, being physically active and eating a healthy diet. We want to stop cancer before it starts.

Why is cancer research important?

Currently, one in two people in the UK will be diagnosed with cancer, and all of us can be affected by cancer in some way. That’s why we think it’s vitally important to prevent as many people getting cancer as possible.

With your help, we can fund new research to discover how we can ALL lower our chances of getting cancer, and spread that knowledge far and wide.

Research is expensive because cancer is such a complex disease. Scientists need to be educated and trained, specialist equipment has to be bought or even designed, and to ensure that the evidence is reliable, experiments must be repeated many times over many years.

To help researchers collaborate, we’ve created a database that pulls together all of the research around the world on cancer and diet, weight and physical activity.

Still have questions?

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