Wednesday, February 1

What are the causes of Cancer

The abnormal and uncontrolled growth of cells anywhere in the body is generally called Cancer. A lot of names are given for these abnormal cell masses such as malignant cells, tumor cells, and cancer cells. Many cancerous tissues are also identified by their site of origin, for example, lung cancer, breast cancer, colon cancer, etc. 

Every cell in the body has a set lifetime. After serving their purpose, the cells naturally die (called apoptosis). But when the cells do not die and start growing uncontrollably then it results in the accumulation of a mass of cells (benign) which is called cancer. Millions of people around the world have beaten cancer because of early detection, accurate diagnosis, and a good personalized treatment plan under the guidance of a highly experienced Oncologist and an interdisciplinary Team, along with the help of a positive attitude and personal strength. These cells also tend to get detached from their site of origin and travel to all the other body parts through circulatory as well as lymphatic systems. The process of cancerous cells leaving their site of origin and moving to any other body part is called Metastasis.  

Factors like age, race, gender, diet, environment, and genetic composition of an individual influence the occurrence of cancer and its types. Thus, the prevalence of cancer and its type varies according to these factors. The World Health Organization (WHO) has provided some cancer information. These are as follows:  

● The leading cause of death all over the world is cancer. It accounts for about 8 million deaths (22% of all deaths) worldwide. 

● Deaths occurring from cancer are continuously rising all over the world and it is estimated that by the end of 2030, this number will reach up to 13 million (70% increase).

Types of Cancer

Some common types of cancer are listed below:

  1. Carcinoma: Cancer that originates from the skin cells and other tissues that cover/line the internal organs such as the lung, pancreas, colon, ovary, etc. is generally regarded as Carcinoma. Squamous, epithelial and basal cell carcinoma, papilloma, melanoma, etc. are some commonly occurring carcinomas. 
  2. Sarcoma: Cancer beginning in cartilages, bones, muscles, fats, and other supportive or connective tissues are called Sarcoma. Some common sarcomas are synovial sarcoma, osteosarcoma, liposarcoma, angiosarcoma, etc. 
  3. Leukemia: The origin of this type of cancer is in the bone marrow (blood-forming tissues). A large number of red blood cells are produced abnormally and enter into the circulatory system.
  4. Lymphoma: Cancer that starts proliferating from the immune system is called Lymphoma. Various types of lymphomas are B-cell lymphoma, T-cell lymphoma, Hodgkin lymphoma, etc.
  5. Cancers of Central Nervous System: As the name suggests, this type of cancer originates from the brain and spinal cord. The examples include gliomas, pituitary adenomas, meningiomas, primary CNS lymphomas, etc.

Causes of Cancer

Anything that may trigger the abnormal growth and development of an otherwise normal cell can be a causative agent for cancer. A large number of factors are present in the environment that can potentially cause cell abnormalities and cancer development. In many cases, the cause of the onset of cancer remains unknown while in other cases the lifestyle, genetic or environmental factors are found to have a role in the development of cancerous cells. Also, there can be more than one cause for the growth and proliferation of abnormal cells. However, it is quite difficult to know the possible event or agent that triggers the formation of cancerous cells. The researchers have provided us with many potential carcinogens that are found to cause cancer either alone or in combination with other cancer-causing agents. These are:

●       Toxic Chemical Compounds: Some chemical compounds released from various industries such as benzene, vinyl chloride (plastic), asbestos, N-nitrosamines, benzidine, etc. are potential carcinogens. Certain heavy metals such as nickel, cadmium can also cause cancer when ingested inside the body. Cigarette smoke and tobacco are known to have around 66 potential cancer-causing chemicals. 

●       Radiation: Ultraviolet (UV) rays from sunlight are also reported to cause cancer. Other ionizing radiations emitted due to human activities such as radiations from uranium, radon, alpha, beta, gamma rays, and X-rays can also cause cancer.

●      Pathogens: Some bacterial and viral pathogens such as Human Papilloma Virus (HPV), hepatitis virus, Epstein-Barr Virus (EBV), Schistosoma species, Helicobacter pylori, etc. are also known as potential carcinogens.

●         Genetics: Various types of specific cancers such as breast cancer, ovarian cancer, prostate cancer, etc. have been associated with human genetic makeup and heredity.

●         Other risk factors: Many other risk factors are recently added to the list of potential carcinogens. The International Agency for Research on Cancer has classified red meat like pork, beef, and lamb as a high-risk potential carcinogen. Along with this, processed meats such as smoked, salted, preserved, and cured meats have also found their place in the list of potential carcinogens. People who eat barbecued meat now and then have an increased risk for the advent of cancer as at high temperatures certain cancer-causing compounds such as nitrites and polyaromatic hydrocarbons are formed.

● Many other situations that may increase the risk of developing cancer include obesity, chronic inflammation, lack of exercise, and hormones, particularly the hormones which are used for replacement therapy. 

● Cell phones have recently been heavily studied in the research of the advent of cancer. In the year 2011, the World Health Organization (WHO) classified cell phone’s low-energy radiation as a possible carcinogen but it is placed on a very low-risk level. 

It is important to note that almost everyone is surrounded by the risk factors for developing cancer or is exposed to carcinogens throughout their life but not everyone gets cancer. Many individuals also have genes linked to the onset of cancer but they do not certainly develop it. Why? Although there is no satisfactory answer for this question, it should be kept in mind that the higher the number of carcinogens an individual is exposed to, the higher will be the chance for him to develop cancer. Similarly, individuals with genetic makeup linked to cancer may not necessarily develop it because of a lack of stimulus to make the gene function. Some people may also have a strong immunity that can get rid of the potential cancer-causing cells. For these reasons, it is difficult to assign a specific cause of cancer to the entire population.