What is Cancer?
The human body is made up of billions of cells which form the building blocks of our tissues and organs. The replication of these cells is what gives it the ability to form complex systems that support life forms. The abnormal or uncontrolled replication of these cells is known as cancer. There are over 200 different types of cancer, but the most common ones are breast cancer, prostate cancer, lung and bronchial cancer, colon and rectum cancer, bladder cancer, melanoma of the skin, non-Hodgkin lymphoma, kidney and renal cancer, thyroid cancer, leukemia, pancreatic cancer and cervical cancer.
How Does Cancer Develop ?
Cancer develops as a result of genetic damage in normal cells in the human body. The damage can be caused by congenital factors or other external factors relating to food, environment or lifestyle. The cell contains genes that determines how the cell’s proteins are to be produced. Cancer develops when a string of mutations occur in the genes that govern the cell’s ability to divide and multiply. These mutations often lead to an over-stimulation of cell growth making it to grow uncontrollably.
How Does Cancer Spread?
The place where a cancer originates in the body is called the primary site or primary cancer. If cancer cells spread to another part of the body, the new area is referred to as a secondary cancer or a metastasis. Some cancers can spread to more than one area of the body leading to the formation of multiple secondaries or metastases. There are several mechanisms by which cancer spreads. Cancer cells can be carried in the lymphatic system or blood stream to other parts of the body. In order to spread, some cells from the primary cancer must split, and move to another part of the body and start growing there. If the cancer cells go into small blood vessels they can secure access into the bloodstream (circulating tumor cells).
How Cancer is Detected
Cancer is usually diagnosed by an expert who has visualized the cell or tissue samples under a microscope. In some other instances, specific test are carried out on the proteins, DNA, and RNA of the cells which can help physicians determine if there is cancer. These Tests are very important as they can detect many other kinds of diseases and conditions. For example, if doctors are not sure a lump is cancer, they may cut a little piece of the lump and have it tested for cancer or other conditions that can cause growths that may look like cancer.
Laboratory Test for Cancer Detection
The level of certain substances in the body (high or low) can be a sign of cancer. Laboratory tests are conducted using samples such as blood, urine, or other body fluids that measure the levels of these substances. The results of the test help doctors to reach a diagnosis. However, this parameter is not a definitive clue or sign of cancer, other parameters must be matched before a conclusion can be reached. Stand-alone laboratory tests are not used for cancer diagnosis.
Imaging Procedures
Imaging procedures relies on the creation of pictures of certain areas of the body that help the physician see whether a tumor is present. Imaging procedure in cancer detection include:
- CT scan: this involves the use of an x-ray machine that is linked to a computer which takes a series of detailed pictures of body organs. Dye or other contrast material may be administered to highlight areas inside the body, making the pictures easier to read.
- Nuclear scan: for this scan, an injection of a small amount of non-toxic radioactive material, which is sometimes called a tracer is given. It travels through the bloodstream and settles in certain bones or organs. A scanner then detects and measures the radioactivity. The scanner creates pictures of the bones or organs on a computer screen or on a film for interpretation and inference.
- Ultrasound: an ultrasound device emits sound waves that humans cannot hear. The waves bounce off tissues inside the body like an echo. Using these echo, the computer creates a picture of areas inside the body (sonogram).
- MRI: magnetic resonance imaging involves the use of computer linked to a strong magnet used to make detailed pictures of areas of the body.
- PET scan: these scans show how organs and tissues are working. Under this procedure, an individual receives an injection of a tracer before the machine takes 3D pictures that show where the tracer collects in the body.
- X-rays: X-rays employ the use of low dose radiation to create pictures showing the inner parts of the body.
Biopsy
A biopsy is a procedure which involves the removal of a sample of tissue. The sample can be removed in many ways .These include:
- With an instrument called an endoscope(endoscopy)
- With a needle: The doctor uses a needle to withdraw tissue or fluid. (fine needle aspiration biopsy)
- With surgery: Surgery may be excisional (removes the entire tumor) or incisional (removes just part of the tumor).
A pathologist then looks at the tissue under a microscope to determine if it is cancer
