What is Cancer?
Cancer is a class of diseases characterized by out of control cell growth. There are over 100 different types of cancer. Cancers are classified according to the site of the original or primary cancer for example: breast cancer, liver cancer, colorectal cancer.
Cancer occurs when a damaged cell divides uncontrollably to form lumps or masses of tissue called tumors. In the case of leukemia the abnormal cell division occurs in the blood stream. The growth of these tumors interferes with many of the systems of the body. They also release hormones which alter body functions.
Cancerous or malignant tumors are formed when a cancerous cell is transported by the blood or lymph system invading the tissue of some part of the body. The cell then grows and divides making new blood vessels to feed itself.
Metastatic cancer occurs when cells from the primary site are transported to another part the body by the blood or lymph system. They invade the tissue and grow uncontrollably to form a secondary tumor. 90% of cancer deaths are due to metastatic cancers.
How are Cells Damaged?
Each of the billion or so cells in the human body contains the same DNA, a unique blueprint which determines all of the characteristics of an individual. The thousands of genes found in every cell are units of information which tell our bodies which proteins to make based on the type of cell and its needs. Cancerous cells have damaged or mutated genes in the DNA of the cell.
There are many genes in our bodies that control how our cells divide and grow. These include:
Oncogenes which signal cell division
Tumor suppressor genes which signal cells when not to divide
Suicide genes which control the life cycle of the cell and signal a cell to kill itself if something goes wrong
DNA repair genes which instruct a cell to repair damaged DNA
Cancer occurs when the cell’s genetic mutations make the cell unable to correct the DNA damage and unable to signal a cell to commit suicide. Mutations to the oncogenes and tumor suppression genes result in uncontrollable growth.
What Causes Genetic Mutations?
There are many causes of genetic mutations which can result in a cancer diagnosis. Some of the causes which have been identified are connected to specific cancers:
UV radiation from exposure to sun (more recently also from tanning studios) has long been identified as the cause of skin cancer.
Smoking and exposure to second hand smoke is the leading cause of lung cancer.
Asbestos as a cause of cancer and other diseases of the lungs has also been known for some time.
In the past twenty years scientists around the world have been making great strides in discovering the causes of cancer. In the case of breast cancer, twenty years ago the known causes of breast cancer were exposure to radiation and that it had something to do with hormones. Today there are many causes of breast cancer which have been identified.
The first causes to emerge from these studies were associated with lifestyle choices such as diet, exercise healthy, body weight and the use of tobacco products and alcohol. More recent studies have added toxic chemicals in consumer products and the environment to the list of causes. Viruses such has the human papilloma virus (HPV) have been linked to cancer of the cervix, penis and recently to oral cancers. Researchers are also conducting studies focusing on bacteria as a cause of cancer.
If the knowledge about the causes of cancer increases at the rate which has been achieved in the last twenty years, many more prevention strategies can be put in place to reduce the number of people diagnosed with cancer.
There are many risk factors which could increase the risk of a cancer diagnosis. Most people who have one or more risk factors never develop the disease. Others with no apparent risk develop cancer. It is difficult in not impossible to determine exactly which factor(s) caused the cancer to develop.
Some risks such as a person’s age, gender, heredity, or race cannot be changed. Others are linked to personal lifestyle choices such as diet, physical activity, maintaining a healthy weight, smoking and alcohol consumption. There are an ever increasing number of scientific studies which indicate that exposure to toxic chemicals in our homes, workplaces and community and the environment also increases risk.
Cancer is the leading cause of death in Canada accounting for 30% of all deaths. In the next 15 years the number will rise new cases of cancer by 40%. The Canadian Cancer Statistics 2017, an annual report issued by the Canadian Cancer Society, estimates 206,200 new cases of cancer (up from 202,400 in 2016) and 80,00 deaths (up from 78,000 in 2016) will occur in Canada. In Manitoba an estimated 6,700 new cases of cancer in 2017, (down from 6,900 in 2016)and 2,900 deaths (up from 2,800 in 2916) will occur.
Statistics are just numbers. Behind each of the numbers is a person whose life has been turned upside down when they were diagnosed with cancer regardless of where the cancer has developed. The words “You have cancer.” begins a journey no one would willingly choose to take. Cancer effects a person not only physically but also emotionally, spiritually and often financially. Family, friends, colleagues, and communities are also effected.
Canadian Cancer Society Canadian Cancer Statistics 2017 http://www.cancer.ca/~/media/cancer.ca/CW/cancer%20information/cancer%20101/Canadian%20cancer%20statistics/Canadian-Cancer-Statistics-2017-EN.pdf?la=en
Canadian Cancer Society Canadian Cancer Statistics 2016