Cancer (overview)
Le cancer is a dreaded disease, often perceived as “the worst disease”. It is the leading cause of death before the age of 65, in Canada and France. More and more people are being diagnosed with cancer these days, but luckily many are recovering from it. |
There are over a hundred varieties of cancer, or malignant tumor, which can become lodged in different tissues and organs.
In people with cancer, some cells multiply in an exaggerated and uncontrolled way. The genes of these deregulated cells have undergone alterations, or mutations. Sometimes the cancer cells invade surrounding tissue, or break away from the original tumor and migrate to other areas of the body. Those are the ” metastases ».
Most cancers take several years to form. They can appear at any age, but they are more often found in people aged 60 and over.
Remark. benign tumors are not cancerous: they are not likely to destroy nearby tissue and spread throughout the body. They can, however, put pressure on an organ or tissue.
Causes
The body has a panoply oftools to fix genetic “mistakes” or outright destroy potentially cancerous cells. However, sometimes these tools are defective for one reason or another.
Several factors can accelerate or cause the emergence of cancer. Moreover, it is believed that it is most often a set of risk factors that lead to cancer. THE’age is an important factor. But it is now accepted that about two-thirds of cancer cases are attributable to life habits, mainly to smoking andfood. Exposure to carcinogens present in theenvironment (air pollution, toxic substances handled at work, pesticides, etc.) also increases the risk of cancer. Finally, the hereditary factors would be responsible for 5% to 15% of cases.
Statistics
- About 45% of Canadians and 40% of Canadian women will develop cancer in their lifetime82.
- According to the National Cancer Institute, in 2011, there were 365 new cases of cancer in France. That same year, the number of cancer-related deaths was 500.
- One in 4 Canadians will die of cancer, regardless of gender. Lung cancer is responsible for more than a quarter of cancer deaths.
- More cancer cases are being diagnosed than before, in part due to the aging of the population and because it is being detected more
Cancer around the world The most common types of cancer vary from region to region of the world. In Asia, cancers of the stomach, esophagus and liver are much more frequent, in particular because the diet of the inhabitants includes a large proportion of very salty, smoked and marinated foods. In Sub-Saharan Africa, cancer of the liver and cervix are very common due to the hepatitis and human papillomavirus (HPV). In North America as well as in Europe, cancers of the lung, colon, breast and prostate are the most common, among other things due to smoking, poor eating habits and obesity. At Japan, consumption of red meat, which has steadily increased over the past 50 years, has increased the incidence of colon cancer by 7 times3. Emigrants generally end up having the same illnesses as the population of their host country3,4. |
Survival rate
No doctor can predict with certainty how cancer will progress or how chances of survival for a specific person. Statistics on survival rates do, however, give an idea of how the disease progresses in a large group of people.
A significant proportion of patients recover definitively from cancer. According to a large survey conducted in France, more than 1 in 2 patients are still alive 5 years after being diagnosed1.
Le cure rate depends on a multitude of factors: the type of cancer (the prognosis is excellent in the case of thyroid cancer, but much less so in the case of pancreatic cancer), the extent of the cancer at the time of diagnosis, cell malignancy, availability of effective treatment, etc.
The most commonly used method of determining the severity of cancer is TNM classification (Tumor, Node, Metastase), for “tumor”, “ganglion” and “metastasis”.
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How cancer appears
Cancer usually takes several years to form, at least in adults. We distinguish 3 steps3 :
- Initiation. The genes of a cell are damaged; this happens frequently. For example, carcinogens in cigarette smoke can cause such damage. Most of the time, the cell repairs the error automatically. If the error is irreparable, the cell dies. This is called apoptosis or cellular “suicide”. When the repair or destruction of the cell does not take place, the cell remains damaged and proceeds to the next stage.
- Sale. External factors will or will not stimulate the formation of a cancer cell. These can be lifestyle habits, such as smoking, lack of physical activity, poor diet, etc.
- progression. The cells proliferate and the tumor forms. In some cases, they can invade other parts of the body. In its growth phase, the tumor begins to cause symptoms: bleeding, fatigue, etc.
Characteristics of a cancer cell
The changes that take place in the genes of the cell when it becomes cancerous are passed on to its descendant cells. |
The different cancers
Each type of cancer has its own characteristics and risk factors. Please see the following sheets for more details on these cancers.
– Cervical cancer
— Cancer colorectal
– Endometrial cancer (body of the uterus)
– Stomach cancer
– Liver cancer
– Throat cancer
– Esophageal cancer
– Pancreatic cancer
– Skin cancer
– Lung cancer
– Prostate cancer
– Breast cancer
– Testicular cancer
– Thyroid cancer
– Bladder cancer
– Non-Hodgkin lymphoma
– Hodgkin’s disease