Cancer is a term used to describe a group of diseases characterized by the
uncontrolled growth and spread of abnormal cells.
These cells can form tumors, invade nearby tissues, and spread to other parts of the
body through the bloodstream or lymphatic system, a process known as metastasis.
Cancer can arise in almost any part of the body and can affect people of all ages,
although the risk increases with age.
Causes of Cancer: Cancer is caused by changes (mutations) in the DNA of cells,
which can be inherited or acquired over a person's lifetime. These mutations can
disrupt the normal processes that control cell growth and division, leading to the
uncontrolled growth of cells characteristic of cancer. Several factors can increase the
risk of developing cancer, including:
Tobacco Use: Smoking tobacco is the single largest preventable cause of
cancer worldwide, responsible for many types of cancer, including lung, throat,
and bladder cancer.
Diet and Lifestyle: A diet high in processed foods, red and processed meats,
and low in fruits and vegetables can increase the risk of certain cancers. Lack
of physical activity, obesity, and excessive alcohol consumption are also risk
factors.
Exposure to Carcinogens: Carcinogens are substances that can cause cancer.
These include chemicals in tobacco smoke, certain viruses (such as human
papillomavirus), and radiation (including ultraviolet radiation from the sun).
Genetic Factors: Some cancers have a genetic component, meaning they run
in families. Inherited mutations in certain genes, such as BRCA1 and BRCA2,
can increase the risk of breast, ovarian, and other cancers.
Types of Cancer: There are more than 100 different types of cancer, which are
classified based on the type of cell they originate from. The main categories of cancer
include:
Carcinomas: Cancer that begins in the skin or tissues that line or cover internal
organs, such as the lungs, breast, and colon.
Sarcomas: Cancer that begins in the tissues that support and connect the body,
such as bone, muscle, and cartilage.
Leukemias: Cancer that begins in blood-forming tissues, such as the bone
marrow, and causes large numbers of abnormal blood cells to be produced and
enter the bloodstream.
Lymphomas: Cancer that begins in the lymphatic system, which is part of the
immune system and helps fight infections. Lymphomas can occur in the lymph
nodes, spleen, and other tissues.
Central Nervous System Cancers: Cancer that begins in the tissues of the
brain and spinal cord.
Symptoms of Cancer: The symptoms of cancer can vary widely depending on the
type and location of the cancer. Common symptoms include:
Persistent cough or hoarseness
Changes in bowel or bladder habits
A sore that does not heal
Unexplained weight loss
Fatigue
Unexplained pain
Skin changes, such as a new mole or a sore that doesn't heal
