Cancer is the generic name for a group of more than 200 diseases. Although there are many types of cancer, they all start due to the abnormal and uncontrolled growth and multiplication of cells. The disease is also known as a neoplasm. The medical science that studies cancer is called Oncology and the oncologist is the professional who treats the disease. Untreated cancers cause serious illness and death.
Normal Body Cells
The human body is made up of trillions of living cells. These normal cells in the body grow, divide and die in an orderly fashion. During a person’s first years of life, normal cells divide more quickly to allow the person to develop. Then, in adulthood, most cells divide only to replace worn out cells or cells that die or to repair damage. How Cancer Begins
Cancer starts when the cells of an organ or tissue in the body start to grow out of control. This growth is different from normal cell growth. Instead of dying, cancer cells continue to grow and form new anomalous cells. Cancer cells can also invade other tissues, something that normal cells do not. Out-of-control growth and invasion of other tissues is what makes a cell cancerous.
The human body is made up of trillions of cells that multiply through a process called cell division. Under normal conditions, this process is ordered and controlled and is responsible for the formation, growth and regeneration of healthy body tissues.
On the other hand, there are situations in which these cells, for various reasons, undergo a change technically called carcinogenesis, and assume aberrant characteristics when compared to normal cells.
These cells lose the ability to limit and control their own growth, and then they multiply very quickly and without any control.
The cells become cancerous due to DNA damage. DNA is an organic compound whose molecules contain the genetic instructions of all cells. We usually look like our parents, because they are the source of our DNA. However, DNA affects us much more than just that.
Some genes have instructions for controlling cell growth and division. The genes that promote cell division are called oncogenes. Genes that slow cell division or cause cells to die at the right time are called tumor suppressor genes. Cancers can be caused by changes in DNA that turn into oncogenes or by deactivating the tumor suppressor genes.
People can inherit anomalous DNA, but most DNA damage is caused by errors that occur when the normal cell is multiplying or by exposure to some element of the environment. Sometimes the cause of DNA damage can be obvious, such as smoking or exposure to the sun. But it is rare to know exactly what caused a person’s cancer.
In most cases, cancer cells form a tumor. However, some cancers, as in the case of leukemia, rarely form tumors. Instead, these cancer cells affect the blood and organs that make blood cells, reaching tissues where they develop.
How Cancer Spreads Cancer
cells often spread to other parts of the body where they begin to grow and form new tumors. This happens when cancer cells enter the bloodstream or lymphatic vessels in the body. Over time, the tumors will replace normal tissue. This process of spreading cancer is called metastasis.
How Cancers Differentiate
Regardless of where the disease spread, the type of cancer takes its name from the place where it originated. For example, breast cancer that has spread to the liver is called metastatic breast cancer, not liver cancer. Likewise, prostate cancer that has spread to the bones is called metastatic prostate cancer, not bone tumor.
Different types of cancer can behave in different ways. For example, lung cancer and skin cancer are very different diseases, which develop in different ways and respond to different types of treatments. For this reason, cancer patients need to be treated appropriately for their specific type of cancer.
Understanding the Different Types of Cancer
The types of cancer can be grouped into broader categories. The main categories include:
- Carcinomas. They start in the skin or in the tissues that line or cover the internal organs. There are a number of carcinoma subtypes, including adenocarcinoma, basal cell carcinoma, squamous cell carcinoma and transitional cell carcinoma.
- Sarcomas. They start in bone, cartilage, fat, muscle, blood vessels or other connective or supportive tissue.
- Leukemias. They start in the tissue that produces blood, such as bone marrow, which causes a large number of abnormal cells to enter the bloodstream.
- Lymphomas and Myelomas. They start in the cells of the immune system.
- Cancers of the Central Nervous System. They start in the tissues of the brain and spinal cord.
Not all tumors are malignant. Non-cancerous tumors are called benign tumors. Benign tumors can cause problems, such as overgrowth and pressure on other healthy organs and tissues. However, they do not invade other tissues and organs. Thus, they do not spread to other parts of the body (metastases).
Cancer is not …
A benign tumor that can usually be removed and that in most cases does not recur (relapse), does not spread throughout the body and does not threaten the patient’s life.
A death sentence, today many patients are successfully treated especially when the disease is diagnosed early.
Is Cancer Common?
Half of all men and a third of women will develop cancer at some point in their lives.
Currently, millions of people are living with cancer or have had and treated a cancer. The risk of developing various types of cancer can be reduced with changes in the person’s lifestyle, for example, not smoking, limiting the time of exposure to the sun, being physically active and maintaining a healthy diet.
On the other hand, there are screening tests that can be performed for some types of cancer, so that an early diagnosis of the disease can be made, when the chances of cure are better and greater than when it is diagnosed in more advanced stages.