What is Cancer?
Find out more about different types of cancers, prevention, early detection and cancer treatment.
Key Cancer Facts
- Cancer ranks as the second leading cause of global death, claiming 10 million lives annually.
- Over 40% of cancer-related deaths are preventable, linked to modifiable factors like smoking, alcohol, poor diet, and inactivity.
- Routine screening and early detection could prevent approximately one-third of all cancer-related deaths.
- A striking 70% of cancer deaths occur in low-to-middle income countries.
- Implementing resource-appropriate strategies for prevention, early detection, and treatment could save millions of lives each year.
- The economic burden of cancer is estimated at a substantial US$1.16 trillion annually.
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 tumour; this is true of all cancers except leukaemia (cancer of the blood). If left untreated, tumours 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.
Tumors can be categorized into three groups: benign, malignant, or precancerous.
Benign tumors are non-cancerous, typically growing slowly and posing a minimal threat to life. They do not spread to other parts of the body and often consist of cells similar to healthy ones. Problems arise only when they become exceptionally large, causing discomfort or exerting pressure on adjacent organs, such as a brain tumor within the skull.
Malignant tumors, in contrast, grow more rapidly than benign ones and have the capacity to invade and destroy nearby tissues. Cells from malignant tumors can detach and spread to other body parts through metastasis. Once in a new location, these cells continue to proliferate, forming secondary sites known as metastases, leading to the condition referred to as metastatic cancer.
Precancerous (or premalignant) refers to a condition involving abnormal cells that may have the potential to develop into cancer.
Types of Cancers
Cancer can be categorized based on the type of cells from which they originate, with five main types:
Carcinoma: Arising from epithelial cells, which form the protective lining of organs, carcinomas have the potential to invade surrounding tissues, organs, and metastasize to lymph nodes and other parts of the body. Common examples include breast, prostate, lung, and colon cancer.
Sarcoma: This malignant tumor affects bones or soft tissues, such as fat, muscle, blood vessels, nerves, and other supportive connective tissues around organs. Common forms include leiomyosarcoma, liposarcoma, and osteosarcoma.
Lymphoma and Myeloma: These cancers originate in immune system cells. Lymphoma affects the lymphatic system throughout the body, while myeloma begins in plasma cells, a type of white blood cell producing antibodies to combat infections. Myeloma can impact the cell’s ability to produce antibodies effectively.
Leukaemia: Characterized by cancerous growth in white blood cells and bone marrow, the tissue responsible for blood cell formation. Various subtypes exist, with examples like lymphocytic leukaemia and chronic lymphocytic leukaemia.
Brain and spinal cord cancers: Referred to as central nervous system cancers, some are benign, while others can exhibit growth and spread.
Causes of Cancer
Various factors contribute to the development of cancer, and similar to many other diseases, most cancers result from exposure to a combination of causal factors. It is crucial to note that, although certain factors are beyond one’s control, approximately one-third of cancer cases can be avoided by mitigating behavioral and dietary risks.
Modifiable risk factors include:
It’s important to recognize that factors such as income and education levels, national policies, industry strategies driven by vested commercial interests, and genetics can make it challenging to address modifiable factors and modify behavior at the individual level.
Alcohol: All types are linked to six cancers, including breast and liver. Risk increases with higher consumption.
Weight: Excess weight raises the risk of 12 cancers, especially bowel and pancreatic. Greater adult weight gain correlates with higher risks.
Diet: Diets high in red/processed meats, salt, and low in fruits/vegetables impact colorectal, nasopharynx, and stomach cancer risks.
Physical Activity: Reduces body fat and associated risks. Lowers the chances of colon, breast, and endometrial cancers.
Tobacco: Contains 80+ cancer-causing substances, leading to lung, mouth, and other cancers. Duration and intensity of smoking escalate risks.
Ionizing Radiation: Manmade sources and UV radiation (sun, lamps) pose cancer risks. Fair-skinned or those with family history are more susceptible.
Workplace Hazards: Some jobs expose individuals to cancer-causing substances, e.g., chemical dye industry workers and asbestos-related risks.
Infections: Viruses contribute to 2.2 million cancer deaths yearly. Examples include HPV (cervical cancer), Hepatitis B/C (liver cancer), and Epstein-Barr (lymphomas). Helicobacter pylori infection increases stomach cancer risk.
Non-modifiable risk factors include:
Age: Cancer risk increases with age due to prolonged exposure to carcinogens and the potential for genetic mutations to accumulate over time.
Cancer-Causing Substances (Carcinogens): Substances altering cell behavior can increase cancer risk. Mutations in genes, the cell’s coded messages, contribute to the likelihood of cancer development.
Genetics: Genetic predisposition, inherited high risk, increases the likelihood of certain cancers. For example, BRCA1/BRCA2 carriers have a higher predisposition to breast cancer, though genetic factors contribute to a small percentage of cases.
Immune System: Weakened immune systems, as seen in organ transplant recipients, HIV/AIDS patients, or those with conditions suppressing immunity, elevate the risk of certain cancers.
Signs and Symptoms of Cancer
Cancer symptoms vary depending on the type and location, but key signs include:
Lumps or Swelling: Cancerous lumps are often painless and may grow over time.
Respiratory Issues: Persistent cough, breathlessness, or difficulty swallowing should be noted.
Bowel Changes: Keep an eye on alterations in bowel habits, including constipation, diarrhea, or blood in stools.
Unexpected Bleeding: Unexplained bleeding from the vagina, anus, or blood in urine or coughing.
Unexplained Weight Loss: Rapid, unintentional weight loss over a few months.
Fatigue: Extreme tiredness and lack of energy, often accompanied by other symptoms if due to cancer.
Pain: Ongoing or intermittent unexplained pain.
Skin Changes: Monitor new moles or alterations in size, shape, color, or texture.
Urinary Issues: Urgency, frequency, inability to urinate, or pain during urination.
Breast Changes: Observe changes in size, shape, feel, skin, or pain in the breast.
Appetite Loss: Prolonged reduced hunger.
Non-Healing Sores: Sores, wounds, or mouth ulcers that won’t heal.
Heartburn or Indigestion: Persistent or painful heartburn or indigestion.
Night Sweats: Particularly heavy and drenching night sweats.
Preventing over a third of all cancers involves minimizing exposure to risk factors like tobacco, obesity, inactivity, infections, alcohol, environmental pollution, occupational carcinogens, and radiation.
Vaccination against Hepatitis B Virus (HBV) and Human Papilloma Virus (HPV) can effectively prevent liver and cervical cancers, respectively.
Additionally, curbing exposure to environmental pollution, occupational carcinogens, and radiation is crucial for preventing additional cases of cancer.
Early detection of cancer
Early identification of certain cancers significantly enhances the likelihood of successful treatment with fewer side effects and lower costs. Cost-effective tests are available for early detection of colorectal, breast, cervical, and oral cancers, and ongoing research is developing tests for other cancer types.
Consult your doctor to understand national recommendations on vaccinations, testing, and screenings, as these guidelines may differ between countries.
Managing and Treating Cancer
Treatment for cancer depends on factors like cancer type, location, size, spread, and overall health. Common treatments include:
- Removes the entire cancer when it has not spread, potentially curing the disease.
- Effective for cancers like prostate, breast, or testicular.
- Uses high-energy rays to shrink tumors or destroy cancer cells.
- Administered alone or combined with other treatments.
- Utilizes chemicals to disrupt cell division and damage DNA, causing cancer cells to self-destruct.
- Targets rapidly dividing cells, including cancer cells.
Essential for treating metastasized cancers, particularly in leukemia and lymphoma.
- Boosts the body’s immune system to combat cancer.
- Can treat the entire body by shrinking tumors.
- Alters hormone production to stop or eliminate the growth of hormone-related cancers, like breast and prostate cancer.
- Aims to replace damaged genes with functional ones, addressing the root cause of DNA damage in cancer cells.
- Some approaches focus on damaging cancer cell DNA to trigger self-destruction.
- Still in early stages, with no established successful treatments.
Consult with your healthcare provider to determine the most suitable treatment based on individual circumstances.