What Is Cancer?

oncology_basic

 

Cancer – put in simple terms – is an uncontrolled and abnormal division of body cells. Cancer can affect all body parts including the skin, blood, brain, bones and so on. Due to the diversity of its origin, more than 200 cancer types have been identified so far.

The disease of the century

According to a recent report by the American Cancer Society, there are more than 13.7 million Americans with a history of cancer. That is not all. Cancer is spreading more rapidly than scientists initially anticipated. According to the same report, more than 1.65 million new cancer cases are reported in America every year (see below Source no. 1).

Fortunately, due to rigorous ongoing research in this field, the prognosis of cancer is improving.

How does Cancer Start?

Our bodies are made of trillions of dividing cells. The division of these cells is very precise, as the body controls how many times each cell should divide. But, sometimes the balance of cell division is disturbed, and cells start to divide aberrantly.

When cells divide in an uncontrolled manner, it represents the beginning of cancer. These abnormally dividing cells invade the surrounding tissues and can even spread to distant body parts.

Cells become cancerous when abnormalities sprout in the cell DNA (Deoxyribonucleic acid). Think of DNA as the mainframe computer that controls each and every activity of a cell. Your DNA tells every cell how many times it should divide. But when the DNA becomes defective, this affects the division patterns of cells.

Is Cancer Always Genetic?

Thanks to our evolving knowledge of the human genome and human body, we have been able to identify numerous causes that might trigger cancer. Genes play a very important role in cancer development, but maybe not as much as we initially thought.

There are a lot of environmental factors, other than genetics, which have been recognized to cause cancer. Luckily, these causes can be avoided or mitigated.

According to research at the Harvard School of medicine, environmental factors contribute a great deal to cancer development. Researchers found that smoking, alcohol abuse, obesity, decreased intake of fruits and vegetables, and infections – like Human Papillomavirus (HPV) – are leading environmental causes of cancer worldwide (see below Source no. 2).

In most of the cases, the cause of cancer is environmental; therefore, lifestyle changes can help avoid cancer development. Such lifestyle changes include:

  • Smoking cessation
  • Avoiding alcohol
  • Adequate physical activity
  • Limited intake of fried and fatty foods
  • Leading a stress-free life
  • Preventing radiation/ pollutant/ sun exposure
  • Timely vaccination and so on (Source no. 3 & 4).

What are the Main Types of Cancer?

Cancer can be broadly classified into six different categories, depending on its origin (Source no. 5):

  • Carcinoma: The lining of cells that covers our skin or inside of our organs is called “epithelium.” If cancer appears in these epithelial cells, it is called carcinoma. Almost 90% of cancers are carcinoma.
  • Leukemia: Blood-borne cancers are called leukemia. There are different blood cell types in a human body (red blood cells, white blood cells, and platelets). Leukemia can affect any of these cell lineages.
  • Lymphoma: Cancers that affect the cells of our immune system are called lymphoma. Immune cells are of two basic varieties: T cells (that engulf foreign invaders) and B cells (these cells produce antibodies).
  • Sarcoma: These cancers usually emerge from cells in body parts like bones, joints, connective tissues, and muscles.
  • Adenoma: This cancer type affects gland-like structures in the body, like thyroid gland, pituitary gland, etc.
  • Nervous system tumors: These tumors affect the brain, spinal cord and their covering (meninges).

What are the common Cancer Symptoms?

The symptoms of cancer cannot always be predicted owing to the variable nature of different cancer types. Some of the people may not develop any symptoms at all while others may develop prominent symptoms even in the early stages.

The severity of symptoms depends on the site of cancer, its site of spread, its size, its grade, etc. That is why, it is not possible to recognize cancer just by symptoms.

However, there are some standard warning signs that can indicate the presence of cancer. If you experience any of the following symptoms, you should book a doctor’s appointment as soon as possible.

Here are some cancer symptoms you should never neglect (see below Source no. 6):

  • Unexplained weight loss: Most cancer sufferers experience weight loss at some point in the development of the disease. If you lose weight for no apparent reason (if you have unexplainably lost more than 10 pounds / 4.5kg in the past weeks), this can be an early indication of cancer.
  • Fatigue: Cancer cells derive a lot of energy for their growth and leave you fatigued and breathless. If you have the kind of fatigue that does not go away when you rest or when following an anti-fatigue treatment, you should get yourself checked.
  • Fever: Fever is a very important symptom of many cancer types, especially cancers affecting blood cells- leukemia and lymphoma. If you have a persistent, low-grade fever that does not get better with fever relieving medicine, your body might be sending you an alarm signal.
  • Malaise and body pains: A generalized feeling of being unwell, the inability to eat properly, having body aches and pains, all are commonly associated with cancer.
  • Specific Symptoms: Look out for specific symptoms that are linked to specific types of cancer:
    • Any skin changes, change in skin color or texture, and non-healing skin sores might be the earliest symptoms of skin cancer.
    • Changes in bowel habits, blood in stool, abdominal pain and improper digestion are some important features of colorectal cancer.
    • Poorly healing skin wounds, excessive bleeding, fever, repeated infections and weight loss are key symptoms of blood-borne cancers.
    • Difficulty in breathing, coughing blood or chest pain are things to look out for in cases of lung cancer.

Cancer FAQs.

  1. Are all tumors cancerous?

No. No, all tumors are not cancerous. Tumors can be divided into two main types depending on their potential to spread: malignant tumors (that spread to other sites) and benign tumors (that do not spread).

  1. Is cancer contagious?

No. Cancers are not contagious, and they do not spread from one person to another. There is no scientific evidence that kissing, having sex or being close to someone with cancer causes cancer in the healthy person.

  1. Can cancer be treated?

Our understanding of different cancer types is evolving, and we are developing new ways to treat cancers. Due to advancements in treatment strategies, the prognosis of cancer has improved significantly.

  1. Can cancer reappear after treatment?

Yes, the chances of recurrence are high with some cancer types.

  1. How is cancer treated?

Cancer therapies include surgery, chemotherapy, radiotherapy and alternative medicine. There is a lot of new data supporting the use of complementary medicine for cancer treatment.

Cancer is the uncontrolled division of body cells, which can affect any part of the human body. Besides genetics, environmental factors contribute a great deal to cancer development, which means a healthy lifestyle can reduce the chances of cancer. It is important that you know the common cancer symptoms to wipe away any confusions.

If you or someone dear experience symptoms that might indicate the presence of cancer, book a doctor’s appointment as soon as possible. The sooner you take action to cure cancer, the greater chances you have to combat it.

 

Sources & References:

  1. Cancer facts & Figures, 2014.
  2. Lancet. 2005 Nov 19;366(9499):1784-93.
  3. Pharmaceutical research. 2008 Sep; 25(9): 2097–2116.
  4. Nature reviews. Nat Rev Cancer. 2006 Jan;6(1):75-83.
  5. National cancer institute, 2015.
  6. American Cancer Society, 2015.

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