What is cancer ?
Cancer is a disease which occurs when changes in a group of normal cells within the body lead to uncontrolled, abnormal growth forming a lump called a tumor; this is true of all cancers except leukemia (cancer of the blood). If left untreated, tumors can grow and spread into the surrounding normal tissue, or to other parts of the body via the bloodstream and lymphatic systems, and can affect the digestive, nervous and circulatory systems or release hormones that may affect body function.
Cancer can be divided into three groups: benign, malignant or precancerous.
With so many different types of cancers, the symptoms are varied and depend on where the disease is located. However, there are some key signs and symptoms to look out for, including:
Unusual lumps or swelling – cancerous lumps are often painless and may increase in size as the cancer progresses
Coughing, breathlessness or difficulty swallowing – be aware of persistent coughing episodes, breathlessness or difficulty swallowing
Changes in bowel habit – such as constipation and diarrhea and/or blood found in the stools
Unexpected bleeding – includes bleeding from the vagina, anal passage, or blood found in stools, in urine or when coughing
Unexplained weight loss – a large amount of unexplained and unintentional weight loss over a short period of time (a couple of months)
Fatigue – which shows itself as extreme tiredness and a severe lack of energy. If fatigue is due to cancer, individuals normally also have other symptoms
Pain or ache – includes unexplained or ongoing pain, or pain that comes and goes
New mole or changes to a mole – look for changes in size, shape, or color and if it becomes crusty or bleeds or oozes
Complications with urinating – includes needing to urinate urgently, more frequently, or being unable to go when you need to or experiencing pain while urinating
Unusual breast changes – look for changes in size, shape or feel, skin changes and pain
Appetite loss – feeling less hungry than usual for a prolonged period of time
A sore or ulcer that won’t heal – including a spot, sore wound or mouth ulcer
Heartburn or indigestion – persistent or painful heartburn or indigestion
Heavy night sweats – be aware of very heavy, drenching night sweats
Over a third of all cancers can be prevented by reducing your exposure to risk factors such as tobacco, obesity, physical inactivity, infections, alcohol, environmental pollution, occupational carcinogens and radiation.
Prevention of certain cancers may also be effective through vaccination against the Hepatitis B Virus (HBV) and the Human Papilloma Virus (HPV), helping to protect against liver cancer and cervical cancer respectively.
Reducing exposures to other carcinogens such as environmental pollution, occupational carcinogens and radiation could help prevent further cancers.
Early detection of cancer
There are a number of cancers which can be identified early which helps to improve the chances of successful treatment outcomes, often at lower costs and with fewer (or less significant) side effects for patients. There are cost-effective tests that help detect colorectal, breast, cervical and oral cancers early and further tests are being developed for other cancers.
Check with your doctor for guidance on the national recommendations regarding vaccinations, testing and screenings. These can and do vary from country to country.
The classification of cancer by anatomical extent of the disease, i.e. stage, is essential to patient care, research and cancer control. The UICC TNM staging system is the common language adopted by oncology health professionals to communicate on the cancer extent for individual patients. Once the stage of cancer is known and understood, this is often a basis for deciding appropriate treatment and individual prognosis. It can also be used to inform and evaluate treatment guidelines, and constitutes vital information for policy-makers developing or implementing cancer control, prevention plans and research.
The TNM classification focuses on the anatomical extent of the tumor and is determined by assessing the following categories:
- T describes the size of the main (primary) tumor
- N describes whether the cancer has spread to the nearby lymph nodes
- M describes whether the cancer has metastasized (spread from the primary tumor to another part of the body)
Managing and treating cancer
Your treatment depends on the type of cancer, where your cancer is, how big it is, whether it has spread, and your general health. The general types of treatments include: surgery, chemotherapy, radiotherapy, hormone therapy, immunotherapy, and gene therapy.
If a cancer has not metastasized (spread), surgery can remove the entire cancer which may completely cure the disease. Often, this is effective in removing the prostate or a breast or testicle.
Radiation treatment or radiotherapy uses high-energy rays to reduce a tumor or destroy cancer cells as a stand-alone treatment and in some cases in combination with other cancer treatments.
Chemotherapy uses chemicals to interfere with the way cells divide – damaging of DNA – so that cancer cells will destroy themselves. These treatments target any rapidly dividing cells (not necessarily just cancer cells), but normal cells usually can recover from any chemical-induced damage while cancer cells cannot. Chemotherapy is generally used to treat cancer that has spread or metastasized because the medicines travel throughout the entire body. It is a necessary treatment for some forms of leukaemia and lymphoma.
Immunotherapy uses the body’s own immune system to fight the cancer tumor. Immunotherapy may treat the whole body by giving an agent that can shrink tumors.
Several cancers have been linked to some types of hormones, including breast and prostate cancer. Hormone therapy works to change hormone production in the body so that cancer cells stop growing or are killed completely.
The goal of gene therapy is to replace damaged genes with ones that work to address a root cause of cancer: damage to DNA. Other gene-based therapies focus on further damaging cancer cell DNA to the point where the cell destroys themselves. However, gene therapy is new and has not yet resulted in any successful treatments.