Cancer is a class of diseases characterized by out-of-control cell growth. There are over 100 different types of cancer, and each is classified by the type of cell that is initially affected. Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tumors (except in the case of leukemia where cancer prohibits normal blood function by abnormal cell division in the blood stream). Tumors can grow and interfere with the digestive, nervous, and circulatory systems and they can release hormones that alter body function. Tumors that stay in one spot and demonstrate limited growth are generally considered to be benign.
Cancer symptoms are quite varied and depend on where the cancer is located, where it has spread, and how big the tumor is. Some cancers can be felt or seen through the skin - a lump on the breast or testicle can be an indicator of cancer in those locations. Skin cancer (melanoma) is often noted by a change in a wart or mole on the skin. Some oral cancers present white patches inside the mouth or white spots on the tongue. Other cancers have symptoms that are less physically apparent. Some brain tumors tend to present symptoms early in the disease as they affect important cognitive functions. Pancreas cancers are usually too small to cause symptoms until they cause pain by pushing against nearby nerves or interfere with liver function to cause a yellowing of the skin and eyes called jaundice. Symptoms also can be created as a tumor grows and pushes against organs and blood vessels. For example, colon cancers lead to symptoms such as constipation, diarrhea, and changes in stool size. Bladder or prostate cancers cause changes in bladder function such as more frequent or infrequent urination. As cancer cells use the body's energy and interfere with normal hormone function, it is possible to present symptoms such as fever, fatigue, excessive sweating, anemia, and unexplained weight loss. However, these symptoms are common in several other maladies as well. For example, coughing and hoarseness can point to lung or throat cancer as well as several other conditions. When cancer spreads, or metastasizes, additional symptoms can present themselves in the newly affected area. Swollen or enlarged lymph nodes are common and likely to be present early. If cancer spreads to the brain, patients may experience vertigo, headaches, or seizures. Spreading to the lungs may cause coughing and shortness of breath. In addition, the liver may become enlarged and cause jaundice and bones can become painful, brittle, and break easily. Symptoms of metastasis ultimately depend on the location to which the cancer has spread.
There are numerous methods used to treat cancer. The aim of any treatment is to remove cancerous cells, making sure the cancer does not return. This can be challenging; even if just one cancerous cell remains after treatment, it has the potential to create a new tumour.
The main techniques used to treat cancer are listed below.
This is a common treatment option; however, the type of surgery a person has and when they have it depends on which cancer it is and what stage it is at. Surgery removes the tumour and some normal tissue surrounding it. This is then sent to a laboratory and the results help doctors to decide whether any further treatment is needed, such as radiotherapy or chemotherapy.
In chemotherapy, medicine is used to kill cancer cells. It can be given either as a tablet or directly into a vein, via an injection or infusion. There are over 50 different forms of chemotherapy medication that can be used to treat hundreds of cancer types.
Radiotherapy, also known as radiation treatment, treats many forms of cancer. It can be given outside the body by using X-rays, or inside the body via a liquid that is either swallowed or injected, or by putting radioactive material in or close to the tumour. About 4 out of 10 people with cancer have radiotherapy.
Hormone therapy works by lowering the levels of hormones in your body or by stopping their effects. Prostate cancer in particular needs testosterone to grow, and some breast cancers are stimulated by oestrogen or progesterone.
Monoclonal antibodies are designed to directly target and attack cancer cells. This is why monoclonal antibody therapy can sometimes be referred to as targeted therapy. How often you have treatment and how many treatments you need will depend on which monoclonal antibody you have and the type of cancer.
This involves taking medicines that encourage the immune system to attack cancerous cells. It is often used in the treatment of kidney cancer.
Angiogenesis inhibitor drugs interfere with the development of blood vessels that deliver nutrients and oxygen, which tumours need to survive.