Cancer is a group of diseases characterized by the uncontrolled growth and spread of abnormal cells in the body. If the spread is not controlled, it can lead to death. Cancer occurs when the cell's mechanisms that regulate cell growth are disrupted, leading to excessive cell division and the formation of tumors. Some tumors are benign (non-cancerous) and remain localized, while malignant tumors (cancer) can invade nearby tissues and spread throughout the body via the blood and lymphatic systems (metastasis).

Causes of cancer

Cancer is caused by changes (mutations) in the DNA within cells. These mutations can be triggered by various factors, including:

  • Genetic predisposition : Some people inherit mutations from their parents that increase the risk of cancer.
  • Environmental factors : Exposure to certain chemicals, radiation (including UV radiation from the sun), and certain viruses or bacteria.
  • Lifestyle factors : smoking, excessive alcohol consumption, unhealthy diet, lack of physical activity and obesity.

Common cancers

The most common types of cancer include lung cancer, breast cancer, colon cancer, prostate cancer, skin cancer and stomach cancer.


Cancer symptoms vary depending on the type of cancer and the location of the tumor, but may include:

  • Persistent cough or hoarseness
  • Changes in bowel or bladder function
  • Unintentional weight loss
  • Fever or night sweats
  • fatigue
  • Lumps or thickenings under the skin
  • Skin changes


Cancer is usually diagnosed by:

  • Physical exam : Look for abnormalities that could indicate cancer.
  • Imaging procedures : X-rays, CT, MRI, PET and ultrasound can reveal tumors and metastases.
  • Laboratory tests : Blood, urine and other body fluid tests can reveal abnormalities that indicate cancer.
  • Biopsy : Taking a sample of tissue for microscopic examination to determine whether cancer cells are present.


Treatment for cancer may include a combination of therapies, depending on the type and stage of the cancer, as well as the patient's general health:

  • Surgery : Removal of the tumor and some of the surrounding tissue.
  • Radiation therapy : Use of high-energy radiation to destroy cancer cells or slow their growth.
  • Chemotherapy : Use of drugs to destroy cancer cells.
  • Targeted therapy : Use of drugs or other substances that specifically target cancer cells.
  • Immunotherapy : Strengthening the body's immune system to fight cancer.
  • Hormone therapy : Removing or blocking hormones that promote the growth of certain cancers.


Although not all cancers are preventable, the risk can be reduced through healthy lifestyle habits, including:

  • Do not smoke
  • Limiting alcohol consumption
  • Maintaining a healthy weight
  • Regular physical activity
  • A diet rich in fruits, vegetables and whole grains
  • Protection from the sun's rays

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