Intro to Cancer & Carcinoma

Intro to Cancer & Carcinoma

Cancer is serious, frequently fatal disease. All cancers together are a leading cause of death in many well-developed countries, just behind heart disease. There are hundreds of types of cancer, some of which are very rare and others very common. Cancer can develop in the cells of any organ inside your body and also on your skin.

How does it start?

Cells are the structural and functional units of all living organisms. They can divide and grow. There is a regulatory process which controls the division of cells. Sometimes some cells of our body lose control and start dividing without any brakes. These abnormal cells can be responsible for causing cancer simply by growing excessively and causing destruction of normal tissue.

Sometimes cells growing too much can be felt physically as lumps. Lumps can also be called tumors. If these tumors stay where they form and do not spread from their place of origin, then we call them benign tumors. They are not that harmful. Doctors can simply remove them by surgery if necessary. But, if these abnormal cells destroy normal tissues, and/or spread to other tissues and organs, we call them malignant tumors or cancers. Cells of these malignant tumors called cancer cells. The process by which these cancer cells spread to other parts of the body is called metastasis.

Why does it start?

Cancer cells are dividing in an uncontrolled manner. Why do they lose control? There is no one single answer to this question. There are many factors involved.

There are substances in the environment which can trigger cancer. These include harmful substances like asbestos, pollutants, UV (ultraviolet) rays coming from the sun, certain components of some food and drinks, tobacco, and many others. These cancer-causing agents are called carcinogens. All the cells in the body contain DNA inside the nucleus. DNA is what makes up the genetic blueprint of every individual. The carcinogens affect cellular DNA in ways which damage the regulatory process which controls cell division. Damage to DNA can also be called mutation. Mutations that results in cancer can arise after damage from the environment, but may also be inherited from parents.

Types of cancer

Cancer can be of many types depending on the cells where it originates. If it begins in cells of muscle, cartilage, bones or fibrous tissue it is usually called a sarcoma. If it starts in the bone marrow it is usually leukemia. If it involves the cells of the lymphatic system it is called lymphoma. If it begins in the cells of brain and spinal cord it is called cancer of the central nervous system and if it develops in the outer layer of other organs and tissues we call it carcinoma. These types can be further subdivided.

In general cancer is named according to its place of origin. For example, lung cancer begins in the lungs, gastric cancer begins in the stomach and so on. To be more precise, the cancers are named specifically according to the kind of cells involved. For example, squamous cell carcinoma of the cervix indicates that cancer begins in the squamous epithelial cells of the cervix. Carcinoma accounts for 80 % of all cancers.

Cancer at advanced stages spreads to other organs. These cancers are called “metastatic.” For example, metastatic breast cancer refers to the advanced stage of breast cancer which has spread to other organs.


When a person is having some symptoms that could be caused by cancer, doctors will want to get certain tests done. If a diagnosis of cancer is made, frequently a team of doctors and other healthcare providers are required to diagnose and plan the treatment of a patient.

There are many modern technologies which help doctors locate the cancer and type the cancer. Some of these are ultrasonography, CT scans, PET scans and X-rays. There are specific blood and urine tests which are also helpful to diagnose cancer. Finally, most doctors confirm cancer with the help of a technique called a biopsy, which is used to collect a sample of the abnormal cells.

All of these techniques are used to diagnose, locate cancer and stage the cancer. The stage of cancer is important since it reflects the extent of the spread of the disease. Treatment is planned by the doctors after they receive a complete report of all these tests.


There are many modern therapies in use now. Different types of cancers require different treatment. Broadly there are three kinds of treatments available:

  • Surgery, in which the cancer and surrounding tissue is removed
  • Chemotherapy, in which drugs which kill cancer cells are injected into the body or administered orally
  • Radiotherapy, in which radiation is used to treat the patient
  • Combinations of these therapies
  • Other treatments including cryotherapy (freezing the cancer), heat therapy, and treatment with certain kinds of sound waves.

Even after the treatment is complete patients have to undergo regular check-ups because there are chances of recurrence of the disease. The likelihood of reoccurrence depends on both the type and stage of cancer.


Prognosis refers to chances of survival of a cancer patient. It varies with the kind of cancer and the stage of the cancer when it is diagnosed. There are many other factors that determine prognosis. Some of these are discussed in other sections of this website.

This article was originally published on September 3, 2012 and last revision and update was 9/4/2015.