Cancer (General) / Oncology
Cancer is not a single disease but an umbrella term for a vast group of conditions sharing one defining characteristic: the uncontrolled growth and division of abnormal cells that have the capacity to invade surrounding tissues and, in many cases, spread to distant parts of the body through a process called metastasis. There are more than 200 distinct types of cancer, affecting virtually every organ and tissue in the human body.
How cancer develops
Normal cells grow, divide, and die in an orderly fashion governed by tightly regulated genetic instructions. Cancer arises when damage to DNA — caused by a combination of environmental exposures, lifestyle factors, random copying errors, and inherited genetic mutations — disrupts this regulation, causing cells to proliferate without restraint. Not all mutations lead to cancer; most are repaired or trigger programmed cell death. It is the accumulation of multiple mutations over time that typically transforms a normal cell into a cancerous one.
Risk factors
Risk factors are numerous and vary between cancer types. They include tobacco use (the leading preventable cause of cancer globally), excessive alcohol consumption, obesity and physical inactivity, a diet low in fruit and vegetables, prolonged exposure to ultraviolet radiation, certain viral infections (including human papillomavirus, hepatitis B and C, and Helicobacter pylori), occupational exposure to carcinogens, and inherited genetic predispositions (such as BRCA1/2 mutations for breast and ovarian cancer). Age is itself a significant risk factor, as DNA damage accumulates over a lifetime.
Common symptoms
Cancer can present in many ways. General warning signs include unexplained weight loss, persistent fatigue, a new or changing lump, unexplained pain, changes in bowel or bladder habits, unusual bleeding or discharge, a wound that does not heal, a persistent cough or hoarseness, and difficulty swallowing. Many of these symptoms have innocent explanations, but they should always be investigated rather than ignored.
Diagnosis and staging
Diagnosis typically involves a combination of imaging (CT, MRI, PET scanning), blood tests (including tumour markers), and biopsy — the removal and laboratory examination of a tissue sample. Staging describes the extent to which the cancer has spread and is essential for determining prognosis and treatment.
Treatment
Modern oncology offers a range of treatments, which are frequently used in combination: surgery to remove the tumour, radiotherapy using high-energy radiation to destroy cancer cells, systemic therapies including chemotherapy, targeted therapy, immunotherapy, and hormonal treatments. Palliative care plays a vital role in managing symptoms and maintaining quality of life at all stages of the disease.
Choosing where to be treated
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