Monday 8 November, 2021

Cancer Causes, Stages, and Myths Busted

Dudi Warsito, PhD in Oncology, is a medical writer and researcher at

What we’ll cover in this blog:
– What causes cancer?
– The different stages of cancer
– 5 myths about cancer

What causes cancer?

Check out our latest article What is Cancer and How Does it Occur? in partnership with to learn the science behind how cancer forms. The common denominator to all cancers is that the cells have accumulated several gene changes that make them divide uncontrollably. These cells have lost the ability to control cell division and continue to divide when they shouldn’t. There are various reasons why cancer cells have lost this ability:

Environmental factors
Bacterial and viral infections

Of course, sometimes it’s not possible to know what exactly causes cancer. Let’s take a look at each of these individually and how they can affect cancer:


The vast majority of cancers occur because of lifestyle. Whether it be food, smoking, alcohol, obesity, or sun exposure, many cancer cases every year are correlated to the way lives are led.

For example, smoking is the single biggest factor that increases the risk of cancer that we know of and can do something about. 90% of all lung cancer cases are due to smoking and it is estimated that every second smoker dies from smoking, either as a result of cancer or, for example, cardiovascular disease.

Another important lifestyle factor is the food we eat. There is a strong link between food and cancer (more on this in War On Cancer’s podcast episode with Dr. David Heber). Red and processed meat, grilled meat, foods high in fat are shown to increase the risk of cancer. The World Health Organization (WHO) recommends a varied and nutritious diet. Examples of healthy eating are eating plenty of fruits, vegetables and fiber. Try to eat fish and poultry rather than red meat and charcuterie, and cut down on alcohol, refined sugars and trans fats.

Environmental factors

The environment around us can also lead to cancer – radiation from, for example, radioactive substances or X-rays, radon, environmental toxins or chemicals. Too much UV radiation from the sun is a well-known risk factor for skin cancer.

Older people are at a greater risk of developing cancer because they’ve more likely been exposed to these environmental factors to a greater extent than younger people.

Hereditary cancer

Up to 10% of all cancers are hereditary. This means over several generations, a genetic mutation has been inherited. If you’re born with a mutation, the likelihood of developing cancer, compared to people who have not inherited the mutation, is higher. Inheriting a mutated gene does not mean that you will automatically develop cancer, but that the risk increases.

The knowledge that you carry a mutation linked to cancer means you can also reduce the risk of developing cancer by making lifestyle changes. For example, if several people in the family have suffered from the same form of cancer, it’s a sign that there may be a hereditary mutation in the family. This can be investigated at special clinics in healthcare and with the help of genetic tests. For example, mutations in the BRCA1 and 2 genes are linked to an increased risk of breast cancer, while mutations in the APC gene increase the risk of colorectal cancer. 

If you think you may have a form of hereditary mutation that can be linked to cancer, book a time with your doctor and see if it’s the case. The more you know, the more precautions and monitoring can be done in order to prevent cancer or discover it at an early stage. 


Some cancers stem from infections. For example, it’s well known that human papillomavirus (HPV) can cause cervical cancer. Vaccines against HPV are available for younger girls (approximately 11-26 years). Other viruses linked to cancer include Hepatitis B and C, Epstein-Barr virus and human immunodeficiency virus (HIV). The bacterium Helicobacter pylori can cause stomach cancer and certain lymphomas.

The different stages of cancer

A cancer diagnosis is usually divided into different stages to describe how advanced the cancer is. There are five stages – stage 0 precursor to cancer followed by four stages that represent how advanced the cancer is.

Stage 0: Cells grow rapidly and behave abnormally. They have not spread and are found in the place where they first started growing. This stage signifies that they may be precancerous but isn’t necessarily the case.

Stage I: The cells become more numerous and they begin to lose their normal appearance and function. A superficial and limited tumor has formed, though it may be difficult to detect. No metastases have been detected.

Stage II: The tumor is larger but has not spread.

Stage III: The tumor has become even larger and has begun to spread to surrounding organs and tissues or lymph nodes.

Stage IV: Cancer cells have spread to at least one area beyond nearby organs and tissues or lymph nodes.

5 myths about cancer

Sugar causes cancer

Wrong! Cancer cells consume more sugar (glucose) than normal cells. However, there are no scientific studies that show that sugar causes or worsens cancer. In addition, there are no studies showing that it’s possible to slow down or cure cancer by stopping eating sugar. High consumption of sugar, however, leads to obesity, which in turn increases the risk of getting several forms of cancer, having an indirect effect. 

Cancer is contagious

In general, cancer is not a contagious disease that spreads between people. The only way cancer can spread is through organ or tissue transplantation – a person who receives a new organ from a donor who has had cancer in the past is at greater risk of becoming ill with cancer. However, this risk is very low.

Some cancers such as cervical cancer are caused by viruses. Viruses and bacteria can be transmitted between people, but the cancer they cause is not contagious.

Only smokers get lung cancer

This isn’t true. 90% of all lung cancer cases are due to smoking. The remaining 10% have other causes such as radon, asbestos, air pollution, and radiation.

Passive smoking does not cause cancer

This isn’t true either. Smokers as well as passive smokers have an increased risk of developing lung cancer. Among non-smokers, passive smoking makes up one quarter of all lung cancer cases.

Complementary or alternative medicine can cure cancer

There is no scientific evidence that complementary or alternative medicines cure cancer. However, they have the potential to alleviate the problems that cancer or cancer treatment causes. For example, if you have pain in the body, massage or yoga can relieve the pain.

It’s important to know that some natural remedies such as green tea, ginkgo, valerian and St. John’s wort can have a negative effect on chemotherapy and targeted drug therapy. Always talk to your doctor about any negative effects of herbal remedies.

Dudi Warsito, PhD in Oncology, is a medical writer and researcher at

Keep Reading

Get the latest War On Cancer articles

Share your story today, it will make a difference.