What is cancer?

The human body is made up of billions of cells which together form organs, tissues and bones. Each cell has a nucleus that contains the genes (DNA) that allow it to carry out its role, to multiply and eventually, to die. Each cell has its own safety system to prevent errors from occurring at the gene level. Unfortunately, mutations can arise and successfully evade control mechanisms. These mutations can appear spontaneously (without any cause), be caused by hereditary genetic abnormalities (at birth) or caused by toxic exposures (smoking, alcohol, solvents, etc). When mutations escape the cell’s safety checks, the cell can multiply exponentially, over a period of time that can take days or years, depending on the severity of the disease. This is called cancer. At first, cancer is just a small collection of cells. The more the cells multiply, the bigger the cancer becomes and is likely to spread elsewhere in the body, that is, to become generalized.

According to the Canadian Cancer Society, it is estimated that 2 in 5 Canadians will develop cancer during their lifetime and that approximately 1 in 4 Canadians will die from it.

What are the different types of cancer?

Cancer can affect people of all ages, but remains more common in people older than 50 years old.

There are hundreds of cancers; any organ/tissue can be the primary site of cancer. Cancers are classified into two categories: blood cancers (hematological) and solid cancers (lung, breast, colon …). Each cancer is unique and can evolve in totally different ways from one person to another. Some cancers can be indolent (little aggressive) or very aggressive. Some can be observed (if very slow in evolution), others can be operated while others will require systemic treatments (see Treatments section).

For hematological cancers, see Hematology section.

For so-called solid cancers, there are rare ones and others more frequent. In Quebec, the 4 most common cancers are breast cancer, lung cancer, prostate cancer and colorectal cancer. Breast cancer is the most common form of cancer in women and the second leading cause of cancer death. In men, the most common cancer is prostate cancer. In both women and men, lung cancer is the leading cause of cancer death. Colorectal cancer is the third most common.

For more statistics, see the Canadian Cancer Society, Statistics Section at cancer.ca

What is oncology?

Oncology, also called cancerology, is the study of cancers and their treatments. This is a medical specialization. A doctor who specializes in cancer is an oncologist. As cancer is a complex disease, this specialty requires teamwork with other specialists, such as surgeons and radiation oncologists. Oncology requires multidisciplinary at all levels, from diagnosis to treatment and even after, during the period known as “surveillance”.

What is the role of an oncologist?

The role of an oncologist is multiple: investigate suspicious masses (for example: nodule in the lung, presence of numerous large lymph nodes, etc.), review the investigations already started and confirm the diagnosis of cancer (with the biopsy results). Once the diagnosis is proven and the type of cancer has been identified, the oncologist determines the appropriate treatment plan. Sometimes a surgical referral will be the first step, sometimes systemic treatments will have to be initiated (see Treatments section). Other times, his role is to make a palliative care orientation, that is, the oncologist does not recommend aggressive treatments and favors a comfort care approach (relieving pain, anxiety).

When systemic treatments are administered, the oncologist does a regular follow-up before each treatment to ensure good tolerance and control of possible side effects. When there is partial or complete remission (disappearance of the cancer), the oncologist continues to ensure close monitoring and intervenes as soon as a recurrence is suspected. From beginning to the end of the process, the oncologist pays particular attention to the physical and psychological health of the people under his care. Continually, the oncologist works in collaboration with other health professionals to preserve the quality of life as much as possible. Relatives are always invited to participate in visits, with the patient’s prior consent, of course.

What treatments are available?

Cancer being a complex disease, so are the treatments. As mentioned above, some are operable, others are not. Treatments are classified into two categories, either curative (to cure) or palliative (to control/slow down without being able to cure). The role of the oncologist is to administer so-called “systemic” treatments, that is, treatments that circulate throughout the body. In recent years, cancer research has exploded the quantity of different treatments available. Here is a summary of the main lines of these types of treatments:


A chemotherapy agent is a toxic drug (poison), which can be given alone (monotherapy) or with other agents. Chemotherapy has been used for decades and can be given at the same time as other types of treatment (radiotherapy, immunotherapy, etc.). It is given as an intravenous infusion, subcutaneous/intramuscular injection or as a pill.


Some types of cancer have the ability to hide from or weaken the immune system. Immunotherapy, or biological therapy, is a treatment that involves activating (waking up) the immune system to force it to attack the cancer. It is a treatment that, unlike chemotherapy, gives very few side effects in the majority of cases.

Targeted therapy

This type of treatment uses drugs that specifically target molecules or proteins on/in cancer cells. So unlike chemotherapy, which “poisons” all cells (good or bad), targeted therapy generally targets only cancer cells. For some cancers, isolated mutations have been identified and agents have been created to specifically target these mutations. Several types of targeted therapy exist, such as monoclonal antibodies, anti-TK, anti-VEGF etc.

Hormone therapy

Some cancers (breast, prostate) are dependent on natural hormones produced by the human body. Hormone therapy, or rather « anti-hormones » is a treatment that consists of blocking the receptors or the production of hormones to slow down the cancer.


Comfort treatments, which can be given alone or in combination with systemic treatments (see above), are treatments that aim to relieve discomfort, such as nausea/vomiting, pain, anxiety, etc. This category includes analgesics, anti-nausea, anxiolytics.

During your meetings, your oncologist will explain the type of treatment that applies to your situation and will discuss in detail the options available, the expected benefits and the potential side effects. All the treatments offered are chosen according to the official recommendations of INESSS and are based on the recommendations of oncology experts, at the Canadian and international level. The multidisciplinary oncology team, including nurses, pharmacists, psychologists and other specialists (surgeons, radiation oncologists) will ensure that these treatments limit side effects as much as possible while ensuring to always preserve the best possible quality of life.

Second oncological opinion

Following a cancer diagnosis, if you wish, our oncologist can discuss the diagnosis and the proposed treatment plan with you. An exhaustive review of your file (including imaging and pathology reports) will be done before the meeting and additional examinations may be requested, depending on the situation and your desire. Our oncologist will answer all your questions to the best of his knowledge and can refer you to a center of expertise, if the situation requires it.

Screening and prevention clinic

Can cancer be prevented? In some cases, yes. By changing lifestyle habits and making healthy choices, the risk of certain forms of cancer can be reduced. For advice, come and meet our oncologist who will guide you in changing or maintaining healthy lifestyle habits.

In terms of screening, there are early detection programs for cancer, including breast, prostate, cervical and colorectal cancer. Also, some cancers can be hereditary (passed down from generation to generation) and require closer monitoring. Come talk to our oncologist who will go over your personal and family history, and advise you on the screening tests available depending on your situation. A referral for genetic counseling may also be offered, depending on your family history.

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