The.doctor

Cancer is a leading cause of death worldwide, accounting for nearly 10 million deaths in 2022 (1). The most common in 2022 (in terms of new cases of cancer) were: lung (2.5 million cases) breast (2.3 million cases) colon and rectum (1.9 million cases) prostate (1.5 million cases) skin (non-melanoma) (1.2 million cases) stomach (1.0 million cases). The most common causes of cancer death in 2022 were: lung (1.82 million deaths) colon and rectum (904 000 deaths) liver (760 000 deaths) breast (666 000 deaths) stomach (660 000 deaths). Each year, approximately 400 000 children develop cancer. The most common cancers vary between countries, and cervical cancer is the most common cancer among women in 21 countries, primarily in sub-Saharan Africa. Causes Cancer arises from the transformation of normal cells into tumour cells in a multi-stage process that generally progresses from a pre-cancerous lesion to a malignant tumour. These changes are the result of the interaction between a person's genetic factors and three categories of external agents, including: physical carcinogens, such as ultraviolet and ionizing radiation; chemical carcinogens, such as asbestos, components of tobacco smoke, alcohol, aflatoxin (a food contaminant), and arsenic (a drinking water contaminant); and biological carcinogens, such as infections from certain viruses, bacteria, or parasites. WHO, through its cancer research agency, the International Agency for Research on Cancer (IARC), maintains a classification of cancer-causing agents. The incidence of cancer rises dramatically with age, most likely due to cumulative exposure to risk factors that increase with age. The overall risk accumulation is combined with the tendency for cellular repair mechanisms to be less effective as a person grows older.

May 25, 2026, 7:59 p.m.