Simply put, cancer cells are normal cells in the body that turn into a malignant clone either due to some internal abnormality in the body or some external factor that influences the body over a prolonged period of time. These factors cause irreversible damage or changes to the cell’s normal DNA. Those cells with damaged or altered DNA become free from the general control measures that are present on a normal cell in the body. Loss of control over the growth of these cells leads to uncontrolled multiplication leading to what we see and feel as tumours/cancers.
Elaborating on the causes of cancer, Dr. Wesley M Jose, Associate Clinical Professor, Medical Oncology and Hematology, Amrita Hospital, Kochi says, “Cancer is caused by internal and external factors. Common internal factors include genetic mutations, hormones, immune system-related conditions, overactivation and miscommunication of growth factors, and hereditary changes. External factors are lifestyle, smoking, alcohol consumption, chemical exposure, radiation exposure, viral infections, previous medical treatments with cytotoxic/cancer drugs. These factors can work alone or in conjunction with each other to initiate a normal cell to become malignant.
Common risk factors
“Although doctors have an idea of what may increase your risk of cancer, the majority of cancers occur in people who have no known risk factors,” says Dr. Satyam Taneja, Director, Surgical Oncology, Max Hospital Patparganj .
Factors known to increase your risk of cancer include:
Cancer can take decades to develop. This is why most people diagnosed with cancer are 65 or older. Although more common in older people, cancer is not exclusively an adult disease – cancer can be diagnosed at any age.
Certain lifestyle choices are known to increase your risk of cancer. Smoking, drinking more than one drink per day for women and up to two drinks per day for men, excessive sun exposure or frequent sunburn with blisters, being obese and having unprotected sex can contribute to cancer.
You can change these habits to reduce your risk of cancer, although some habits are easier to change than others.
Your family history
Only a small proportion of cancers are due to an inherited disease. If cancer runs in your family, it is possible for mutations to be passed down from one generation to the next. You may be a candidate for genetic testing to see if you have inherited mutations that could increase your risk of certain cancers. Remember that having an inherited genetic mutation does not necessarily mean you will get cancer.
Your health status
Certain chronic conditions, such as ulcerative colitis, can significantly increase your risk of developing certain cancers. Talk to your doctor about your risk.
The environment around you may contain harmful chemicals that can increase your risk of cancer. Even if you don’t smoke, you could inhale second-hand smoke if you go where people smoke or if you live with someone who smokes. Chemicals in your home or workplace, such as asbestos and benzene, are also associated with an increased risk of cancer.
The genetic mutations you were born with and those you acquire throughout your life work together to cause cancer. Here Dr. Taneja tried to explain in detail—
- What are genetic mutations used for?
A genetic mutation can cause a healthy cell to allow rapid growth, fail to stop uncontrolled cell growth, make mistakes while repairing DNA errors leading cells to become cancerous. These mutations are most common in cancer. But many other genetic mutations can contribute to cause cancer.
- What causes genetic mutations?
Genetic mutations can occur for several reasons, for example: Genetic mutations you were born with. You may have been born with a genetic mutation inherited from your parents. This type of mutation accounts for a small percentage of cancers. Genetic mutations that occur after birth. Most genetic mutations occur after you are born and are not hereditary. A number of forces can cause genetic mutations, such as smoking, radiation, viruses, carcinogenic (carcinogenic) chemicals, obesity, hormones, chronic inflammation, and lack of exercise. Genetic mutations occur frequently during normal cell growth. However, cells contain a mechanism that recognizes when an error occurs and repairs the error. Sometimes an error is missed. It could make a cell cancerous.
- How do genetic mutations interact with each other?
The genetic mutations you were born with and those you acquire throughout your life work together to cause cancer. For example, if you have inherited a genetic mutation that predisposes you to cancer, it does not mean that you are certain to have cancer. Instead, you may need one or more other genetic mutations to cause cancer. Your inherited genetic mutation could make you more likely than others to develop cancer if exposed to a certain cancer-causing substance. It is not known exactly how many mutations must accumulate for cancer to form. This is likely to vary between types of cancer.
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