What is Cancer? An Overview | The Daily Dose
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What is Cancer? An Overview of Causes, Symptoms and Prevention

November 09, 2020 9 min read

Doctor briefing his patient on a diagnosis

Dr. Sandra El Hajj MSc, N-MD, DHSc

Humans lead such different lives across the globe, but we all share one overarching goal: staying healthy and well. While many people are fortunate enough to sustain lifelong health, others may encounter health problems that interfere with their quality of life. Among the many diseases a person may develop, cancer has proven to be one of the most prevalent. The illness has a major impact on societies all over the world, with new diagnoses expected to reach 23.6 million globally by 2030(1)

A chronic condition, cancer can alter an individual’s life and well-being over an extended period of time. While the medical field is now advanced in terms of the measures available to tackle this illness, cancer remains a source of worry and fear for those affected. It’s essential to understand what this condition is, what its symptoms are, what its possible causes and risk factors are and what treatments exist for it. 

What is cancer?

When cells lose control over their growth and hijack normal cells in your body, we refer to it as cancer. The American Cancer Society explains that cancer is not a single disease, as there are many types. This is an illness that can start anywhere in the body: the lungs, colon, breast or blood. While all are called cancers, they are different in the rate of their growth and in the ways they spread(2).

Cancer affects the normal, healthy cell. The body is made of cells that form tissues which make up different organs. When a group of cells begins behaving out of order, damages are likely to occur. Cancer cells divide and reproduce at a continuous pace before overtaking healthy cells and initiating a chronic health condition. This marks the beginning of cancer. 

Cancerous cells can then spread to surrounding cells and tissues, affecting other organs. That’s what’s happened when you hear of someone diagnosed with breast cancer who also went on to develop bone cancer. When cancerous cells spread, it is referred to asmetastasis. But, despite the spread, the cancer is still given the name of the organ where it began. 

Cancer versus tumors: What’s the difference?

In the world of oncology, it’s common to hear two distinctive terms: tumors and cancers. While most people think both refer to the same condition, they’re actually different. 


Cancers have different rates of growth. Some grow rapidly, like in the case of colon or lung cancers, while others grow very slow. Certain cancers also respond differently to the range of treatments offered. Some are eradicated by surgeries while others require chemotherapy. Sometimes, treatments are combined to ensure eradication of cancerous cells. With each individual patient, a doctor will select the type of treatment according to the kind of cancer and which organ(s) it is affecting.


Tumors are lumps that are formed by the accumulation of abnormal cells. In a healthy individual, normal cells regenerate continuously in the body. As the cells age, they die and new cells replace them. When a patient has a tumor, this cycle is disrupted(3). Instead of dying off like normal cells, they keep growing. It’s essential to note that not all lumps are carcinogenic. Some are benign while others are malignant. Benign lumps are harmless while malignant lumps are carcinogenic. It’s also important to note that not all cancers necessarily form tumors. Blood cancer, for example, does not form any mass accumulation.

Doctor examining a tumor under a microscope

The stages of cancer

Since cancer is accompanied by a multiplication of abnormal cells, it’s essential to understand that such growth will eventually progress through several phases. Depending on what stage the cancer is in, the doctor can understand more about the condition and adopt the appropriate treatment. Many tests can be performed to identify the specific stage of the illness. If the cancer involves a tumor, there are five stages to keep in mind that are normally referred to by using roman numerals:

  • Stage zero: This is the stage when there is only an abnormal group of cells that may put the person at risk for developing cancer. It is called a carcinoma in situ
  • Stage one (I): This is the stage when the abnormal cells begin multiplication and have already affected one organ. At this stage, cancer has formed and is referred to as an early-stage cancer.
  • Stage two and three (II)/(III): These two stages are when the cancer begins growing and possibly spreading to surrounding organs. At this stage, treatments like surgeries, radiations and chemotherapy are planned out to help the patient win the fight over this disease.
  • Stage four (IV): This is the final stage of the cancer when the illness has already spread to many parts of the body. It is referred to asmetastatic cancer. At this point, it is hard to treat the illness properly. While doctors do their very best, a patient who has reached this advanced level would look for treatment options to manage symptoms rather than the eradication of the condition.

The cancer phase is normally defined by two elements (4). The first element consists of a thorough physical examination and several tests, which is also known as the clinical stage. The second element is the pathologic stage determined by the tumor sample itself. Many doctors find themselves obliged to take samples of the growing tumor, called biopsies. The doctor may also surgically remove the tumor itself to learn more about it and how it’s affecting the well-being of the individual. Before any decisions are made, it’s essential for the doctor to accurately identify the exact stage in which the patient belongs. This involves the following steps:

  • Decide on the most effective treatment and whether there will be a need for surgery
  • Identify the outlook and understand what the recovery will look like
  • Launch the necessary research by tapping into national hospital databases regarding the most successful treatment plans adapted for that specific case

Cancer symptoms

A chronic condition, cancer is studied the same way as any other illness (5). People who may have cancer can experience the following signs and symptoms:

  • Feeling tired for no particular reason
  • Noticing lumps and thickenings under the skin that can be felt as a growing mass
  • Losing or gaining weight for no particular reason, for example eating well but losing a lot of weight
  • Noticing changes in bowel movements or bladder habits
  • Having trouble breathing or coughing chronically
  • Experiencing difficulty swallowing 
  • Having hoarseness in the voice
  • Feeling continuous muscle and joint pain with no known cause
  • Feeling tired and uncomfortable after eating a meal
  • Noticing changes in the skin like developing sores that do not heal or seeing changes to existing moles
  • Experiencing fevers for no apparent cause
  • Getting bruised or bleeding consistently and unexplainably 

It’s important to note that most of these symptoms can accompany other chronic conditions. If you’re experiencing one of more of these symptoms, it does not necessarily mean that you have cancer. 

Causes of Cancer

Cancer means that some of your cells are behaving abnormally. This abnormal behavior is the result of DNA mutations inside the cell. DNA refers to “deoxyribonucleic acid”. It is the genetic map of every person’s biological building blocks. DNA is essential for every organism on this planet—it’s what makes every individual unique. With its extraordinary powers comes the potential for serious consequences when DNA is damaged. 

On a daily basis, cells’ DNA get damaged due to many biological and environmental factors (6). However, these damages are usually reversible in a healthy individual and DNA can be repaired. When damages are more severe and the body does not have the ability to repair them properly, however, health issues occur. This is the case with cancer.

Gene mutations can occur in two distinctive ways: innately from birth or through exposure after birth. Some individuals are born with genetic mutations that are passed on by their parents. These mutations may lead to cancer; however, this represents a very small percentage of cancer cases. Other mutations can occur later on in life. They are not passed on by parents and people are not born with them. These can be the result of several risk factors including smoking, obesity, chemical exposure, hormones, inflammations and living a sedentary lifestyle. 

Sometimes, mutations acquired from birth and those acquired throughout your life can work together to increase your risk of developing cancer. Those who have inherited a genetic mutation might not necessarily develop cancer until they’re also exposed to environmental mutations. Only then will the disease occur. While a countless number of cancer-related studies are ongoing, many gaps still exist in the understanding of this illness.

Risk factors for cancer

The world of science and medicine has its eyes on cancer: a condition impacting people’s lives and well-being. It’s not only affecting patients’ physical health, but also their mental health. Although many risk factors have been identified, it’s still not completely understood why one person ends up with this illness while another doesn’t. Below, the major risk factors doctors do understand are outlined.


One of the most prevalent risk factors for cancer is age. Statistical studies explain that the median age for developing cancer is 66 years old. This indicates that half of cancer patients are younger than 66 years old while half of them are older. However, it all depends on the type of cancer. For instance, bone cancer is much more common in those who are younger than 20 years old.

Photo of a nurse consoling an elderly patient


Drinking alcohol has been linked to an increased risk of cancer, especially that of the mouth, throat, esophagus, larynx and liver. The higher your alcohol intake, the higher your risk for developing the condition. While some types of alcohol can be good for your well-being—for example, red wine helps keep your heart and blood healthy—drinking it in moderation is key. To add to its controversy, the American Society of Clinical Oncology recently gave a statement linking light alcohol consumption to higher risks of esophageal cancer (7).

Environmental Factors

Having explained earlier about DNA mutations, it’s essential to cover the types of environmental factors that may be facilitating the development of cancer. When you’re exposed to radiation, tobacco smoke, chemicals and UV lights, you’re increasing your risks for developing certain types of cancer. There are many chemicals and substances that are considered to be carcinogenic. Some are found in the air, others in food and even inproducts we use on a regular basis. Among the long list of environmental carcinogens are aflatoxins, arsenic, benzene, asbestos, formaldehyde and vinyl dust: 

  • Aflatoxinsare produced by some molds found in soil. They can be found in contaminated food products like corn, rice, peanuts and sunflower seeds (8).
  • Arsenicis a well known carcinogenic affecting the lungs, skin, bladder and kidneys. It can be found in many foods like seafood, poultry, mushrooms and dairy products (9).
  • Benzeneis a flammable liquid with a sweet odor. It is a potent carcinogenic that is found in many locations like gas stations or factories and is associated with leukemia(10).
  • Asbestosis a kind of fiber that has been linked to many types of cancers like lung cancer. 
  • Formaldehydeis an organic compound that is found in many household products like antiseptics, medicines and cosmetics. 
  • Vinyl dust is a chemical found in vinyl floors and sofas that can increase the risks of developing liver, lung and blood cancer. 

Other factors

Many additional factors can increase your likelihood of developing cancer. Your diet plays a direct role in your health: When you eat healthy food, you’re more likely to stay healthy and well. A diet rich in processed foods, artificial sweeteners and charred meats can increase your risks of developing certain types of cancer. Instead, your diet should include foods that can boost your immune system and protect you from illness. These include cruciferous vegetables,antioxidant-rich foods and foods rich in vitamin D.

Your weight also plays a major role: Obese and overweight people are at higher risks for inflammation and hence, the development of cancer. Other risk factors include not wearing sunblock when exposed to the sun, smoking, hormonal imbalances and having aweak immune system

Some viruses can increase your risk for developing certain types of cancer. This includes hepatitis B and C which may lead to liver cancer, the human papillomavirus that may lead to ovarian cancer, and HIV (the AIDS virus) that may increase your risk of developing lymphomas. 

Finally, a person’s lifestyle has a lot to say about their cancer risks. Having unsafe sex, developing frequent sun blisters, and taking drugs can put you at elevated risks of developing cancer. 

It’s essential to understand the many risk factors that can make you more prone to cancer. While the medical field has advanced, the understanding of this illness remains full of gaps. So, aside from steering clear of these risk factors, you need to eat a healthy diet, maintain your weight at a healthy range, quit smoking and drinking, lower your stress levels, get immunized for certain viruses and avoid excessive sunlight exposure. Try to purchaseclean products that do not contain banned carcinogenic chemicals. 

In summary

Among the many illnesses jeopardizing the health and well-being of individuals, cancer remains a top concern. This is a chronic condition that has imparted a heavy burden on societies worldwide, affecting millions each year. 

Resulting in severe illness and even death, cancer is a disease that deserves everyone’s attention. It’s based on the growth and multiplication of abnormal cells that overtake healthy cells in the body, leading to malfunctions and disruptions in the necessary functioning of organs and tissues. While some are born with mutated genes, others can acquire them from exposure to environmental carcinogens. Understanding and avoiding the risk factors associated with this disease is one of the best things you can do to help prevent it from creeping into your life.

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