Introduction to cancer
Cancer is abnormal cell growth (usually derived from a single abnormal cell). These cells lose their standard control mechanisms and multiply continuously, invade nearby tissues, migrate to other parts of the body, and favor the growth of new blood vessels from which they feed. Malignant (cancer) cells can develop from any tissue in the body.
As they grow and multiply, they form a tissue mass called a tumor, which invades and destroys adjacent normal tissues. The term tumor refers to a group or abnormal growth. They can be malignant or benign. Malignant cells from the original center can spread throughout the body (metastasize).
Types of cancer
Cancerous tissues (malignant neoplasms) remain divided into hematic and hematopoietic tissues (leukemias and lymphomas) and solid tumors (a solid mass of cells), which are often called cancer. Cancerous solid tumors can remain carcinomas or sarcomas. Specific cancers can remain classified according to the organ they first develop and the type of cell in which they arise, for example, squamous cell carcinoma of the skin.
The leukemias and lymphomas are malignant tumors of hematopoietic tissues and hepatic cells, and the immune system. The leukemias arise from cells that produce blood (hematopoietic cells) and displace the production of normal blood cells in the bone marrow. These lymphoma cells dilate the lymph nodes and have large lumps in the armpits, groin, abdomen, or chest.
The carcinomas are malignant neoplasms of the cells lining the skin, lungs, gastrointestinal tract, and internal organs. Carcinomas are skin, lung, colon, stomach, breast, prostate, and thyroid cancer. Characteristically, carcinomas are more common in older age than in youth.
The sarcomas are malignant neoplasms of mesodermal cells. These cells make up muscles, blood vessels, bones, and connective tissue. Examples of sarcomas are leiomyosarcoma (cancer of the smooth muscle found in the wall of the organs of the digestive system). And osteosarcoma (cancer of the bone). Characteristically, sarcomas appear more frequently in youth than in old age.
The following terms remain often used to talk about cancer:
The degree of speed with which a tumor grows and spreads.
Lack of differentiation of cancer cells. That is, the cells do not look like normal cells of the same type of tissue. Anaplastic malignant tumors are usually very aggressive.
Not cancerous. Benign tumors do not invade nearby tissues or spread to distant sites through the bloodstream or lymphatic system (“metastasizing”). However, a benign tumor can continue to grow and cause problems by pressing on nearby tissues.
An agent that causes cancer
Carcinoma in situ (or localized)
Cancer cells that are still within the tissue where they have begun to grow and have not yet invaded nearby normal tissues or spread to other parts of the body.
Complete removal of cancer, which means that the specific tumor does not grow back.
The extent to which cancer cells have matured, stopped multiplying, and adopted normal cellular functions so that they no longer appear as primitive, rapidly multiplying cells
The degree of abnormal appearance of the cancer cells under the microscope; the more anomalous they seem, the more aggressive they are.
The ability of a tumor to grow into surrounding tissues (infiltrate) and destroy them
Cancer cells can invade adjacent tissue and also spread to other parts of the body
The complex procedure by which cancer cells develop from healthy cells
The spread of cancer cells to a new place.
A general term to designate a tumor, be it malignant or benign.
The return of cancer cells after treatment. Either in the initial location or as metastasis (spread).
Absence of any evidence of cancer after treatment, although cancer may remain in the body
The extent to which cancer has spread.
Percentage of people who survive a specified time after treatment.
Abnormal growth or mass
There are many different types of cancer, with other causes and risk factors. In addition, each person has an additional risk of developing various types of cancer. Therefore, there is no single set of preventive strategies that is effective in all cases. However, some general techniques reduce the risk of cancer on many occasions.
Early detection of malignant or premalignant growths saves lives. Therefore, it is essential to undergo the recommended cancer screening tests.
Modifying your diet and lifestyle helps reduce the risk of certain types of cancer. How this risk reduction can remain achieved depends on individual [cancer].
The changes in diet reduce the risk of some cancers.
Drinking less alcohol lowers the risk of cancer of the head and neck, liver, and esophagus.
Reducing fat intake appears to reduce the risk of breast and colon cancer.
Limiting your intake of processed meat and increasing your whole grains and fruits and vegetables can lower your risk of some types of cancer.
The way meat remains cooked can also increase the risk of [cancer]. Grilling or frying meats creates certain chemicals that have remained linked to colon [cancer]. Using other cooking methods reduces the creation of these chemicals and may reduce the danger of colon [cancer].
Smoking is directly related to a third of malignant tumors. Not smoking and avoiding exposure to tobacco smoke dramatically reduces lung, kidney, bladder, and head and neck [cancer] risk. People who quit smoking can also lower their risk of [cancer], and the chances decrease over time. Avoiding smokeless tobacco (inhaled or chewed) reduces the risk of mouth and tongue [cancer].
Being overweight or obese increases your risk of [cancer], especially breast cancer, colon cancer, endometrial [cancer], esophageal [cancer], kidney [cancer], and pancreatic [cancer]. People should try to maintain a healthy weight through diet and exercise. Physical activity itself can reduce the risk of breast, endometrial, and prostate [cancer].
Carcinogens are substances that increase the risk of [cancer]. Some carcinogens, such as asbestos and benzene, can be present in the workplace, and workers in industries that use known carcinogens should take appropriate precautions to avoid or minimize exposure. Other carcinogens occur in the home or the environment. For example, radioactive elements that occur naturally on the planet decay into radioactive radon gas, which can accumulate inside people living in certain areas. Exposure to radon increases the risk of lung [cancer], especially in people who smoke.
Avoiding exposure to the sun (especially at noon) lowers the risk of skin [cancer]. Covering exposed skin and applying broad-spectrum sunscreen products with a sun protection factor (SPF) greater than 30 against UV light types A and B also reduces the risk of skin [cancer].
Vaccines prevent certain types of [cancer] caused by viruses. For example, certain sexually transmitted strains of the human papillomavirus (HPV) cause cervical [cancer], anal [cancer], and some forms of head and neck [cancer]. The vaccination against the human papillomavirus (HPV) virus before first intercourse largely avoids many cases of these types of cancers.
Another example is infection with the hepatitis B virus, which increases the risk of liver [cancer]. Vaccination against this virus helps prevent liver cancer].
Taking aspirin (acetylsalicylic acid) and other non-steroidal anti-inflammatory drugs (NSAIDs) lowers the risk of colorectal [cancer].
The Pap test prevents cervical [cancer] by detecting possible precancerous changes in the cells in this area. Removal of precancerous colon polyps helps prevent colorectal cancers.
Avoiding hormone therapy (for example, estrogen and progesterone) to relieve symptoms of menopause can reduce the risk of breast and endometrial cancers.
Also read: What Are the Assessment of Nutritional Status?